/* binder.c
 *
 * Android IPC Subsystem
 *
 * Copyright (C) 2007-2008 Google, Inc.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <asm/cacheflush.h>
#include <linux/fdtable.h>
#include <linux/file.h>
#include <linux/freezer.h>
#include <linux/fs.h>
#include <linux/list.h>
#include <linux/miscdevice.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/nsproxy.h>
#include <linux/poll.h>
#include <linux/debugfs.h>
#include <linux/rbtree.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/uaccess.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/pid_namespace.h>

#include "binder.h"
#include "binder_trace.h"

static DEFINE_MUTEX(binder_main_lock);
static DEFINE_MUTEX(binder_deferred_lock);
static DEFINE_MUTEX(binder_mmap_lock);

static HLIST_HEAD(binder_procs);
static HLIST_HEAD(binder_deferred_list);
static HLIST_HEAD(binder_dead_nodes);

static struct dentry *binder_debugfs_dir_entry_root;
static struct dentry *binder_debugfs_dir_entry_proc;
static struct binder_node *binder_context_mgr_node;
static kuid_t binder_context_mgr_uid = INVALID_UID;
static int binder_last_id;
static struct workqueue_struct *binder_deferred_workqueue;

#define BINDER_DEBUG_ENTRY(name) \
static int binder_##name##_open(struct inode *inode, struct file *file) \
{ \
        return single_open(file, binder_##name##_show, inode->i_private); \
} \
\
static const struct file_operations binder_##name##_fops = { \
        .owner = THIS_MODULE, \
        .open = binder_##name##_open, \
        .read = seq_read, \
        .llseek = seq_lseek, \
        .release = single_release, \
}

static int binder_proc_show(struct seq_file *m, void *unused);
BINDER_DEBUG_ENTRY(proc);

/* This is only defined in include/asm-arm/sizes.h */
#ifndef SZ_1K
#define SZ_1K                               0x400
#endif

#ifndef SZ_4M
#define SZ_4M                               0x400000
#endif

#define FORBIDDEN_MMAP_FLAGS                (VM_WRITE)

#define BINDER_SMALL_BUF_SIZE (PAGE_SIZE * 64)

enum {
        BINDER_DEBUG_USER_ERROR             = 1U << 0,
        BINDER_DEBUG_FAILED_TRANSACTION     = 1U << 1,
        BINDER_DEBUG_DEAD_TRANSACTION       = 1U << 2,
        BINDER_DEBUG_OPEN_CLOSE             = 1U << 3,
        BINDER_DEBUG_DEAD_BINDER            = 1U << 4,
        BINDER_DEBUG_DEATH_NOTIFICATION     = 1U << 5,
        BINDER_DEBUG_READ_WRITE             = 1U << 6,
        BINDER_DEBUG_USER_REFS              = 1U << 7,
        BINDER_DEBUG_THREADS                = 1U << 8,
        BINDER_DEBUG_TRANSACTION            = 1U << 9,
        BINDER_DEBUG_TRANSACTION_COMPLETE   = 1U << 10,
        BINDER_DEBUG_FREE_BUFFER            = 1U << 11,
        BINDER_DEBUG_INTERNAL_REFS          = 1U << 12,
        BINDER_DEBUG_BUFFER_ALLOC           = 1U << 13,
        BINDER_DEBUG_PRIORITY_CAP           = 1U << 14,
        BINDER_DEBUG_BUFFER_ALLOC_ASYNC     = 1U << 15,
};
static uint32_t binder_debug_mask = BINDER_DEBUG_USER_ERROR |
        BINDER_DEBUG_FAILED_TRANSACTION | BINDER_DEBUG_DEAD_TRANSACTION;
module_param_named(debug_mask, binder_debug_mask, uint, S_IWUSR | S_IRUGO);

static bool binder_debug_no_lock;
module_param_named(proc_no_lock, binder_debug_no_lock, bool, S_IWUSR | S_IRUGO);

static DECLARE_WAIT_QUEUE_HEAD(binder_user_error_wait);
static int binder_stop_on_user_error;

static int binder_set_stop_on_user_error(const char *val,
                                         struct kernel_param *kp)
{
        int ret;
        ret = param_set_int(val, kp);
        if (binder_stop_on_user_error < 2)
                wake_up(&binder_user_error_wait);
        return ret;
}
module_param_call(stop_on_user_error, binder_set_stop_on_user_error,
        param_get_int, &binder_stop_on_user_error, S_IWUSR | S_IRUGO);

#define binder_debug(mask, x...) \
        do { \
                if (binder_debug_mask & mask) \
                        pr_info(x); \
        } while (0)

#define binder_user_error(x...) \
        do { \
                if (binder_debug_mask & BINDER_DEBUG_USER_ERROR) \
                        pr_info(x); \
                if (binder_stop_on_user_error) \
                        binder_stop_on_user_error = 2; \
        } while (0)

enum binder_stat_types {
        BINDER_STAT_PROC,
        BINDER_STAT_THREAD,
        BINDER_STAT_NODE,
        BINDER_STAT_REF,
        BINDER_STAT_DEATH,
        BINDER_STAT_TRANSACTION,
        BINDER_STAT_TRANSACTION_COMPLETE,
        BINDER_STAT_COUNT
};

struct binder_stats {
        int br[_IOC_NR(BR_FAILED_REPLY) + 1];
        int bc[_IOC_NR(BC_DEAD_BINDER_DONE) + 1];
        int obj_created[BINDER_STAT_COUNT];
        int obj_deleted[BINDER_STAT_COUNT];
};

static struct binder_stats binder_stats;

static inline void binder_stats_deleted(enum binder_stat_types type)
{
        binder_stats.obj_deleted[type]++;
}

static inline void binder_stats_created(enum binder_stat_types type)
{
        binder_stats.obj_created[type]++;
}

struct binder_transaction_log_entry {
        int debug_id;
        int call_type;
        int from_proc;
        int from_thread;
        int target_handle;
        int to_proc;
        int to_thread;
        int to_node;
        int data_size;
        int offsets_size;
};
struct binder_transaction_log {
        int next;
        int full;
        struct binder_transaction_log_entry entry[32];
};
static struct binder_transaction_log binder_transaction_log;
static struct binder_transaction_log binder_transaction_log_failed;

static struct binder_transaction_log_entry *binder_transaction_log_add(
        struct binder_transaction_log *log)
{
        struct binder_transaction_log_entry *e;
        e = &log->entry[log->next];
        memset(e, 0, sizeof(*e));
        log->next++;
        if (log->next == ARRAY_SIZE(log->entry)) {
                log->next = 0;
                log->full = 1;
        }
        return e;
}

struct binder_work {
        struct list_head entry;
        enum {
                BINDER_WORK_TRANSACTION = 1,
                BINDER_WORK_TRANSACTION_COMPLETE,
                BINDER_WORK_NODE,
                BINDER_WORK_DEAD_BINDER,
                BINDER_WORK_DEAD_BINDER_AND_CLEAR,
                BINDER_WORK_CLEAR_DEATH_NOTIFICATION,
        } type;
};

struct binder_node {
        int debug_id;
        struct binder_work work;
        union {
                struct rb_node rb_node;
                struct hlist_node dead_node;
        };
        struct binder_proc *proc;
        struct hlist_head refs;
        int internal_strong_refs;
        int local_weak_refs;
        int local_strong_refs;
        void __user *ptr;
        void __user *cookie;
        unsigned has_strong_ref:1;
        unsigned pending_strong_ref:1;
        unsigned has_weak_ref:1;
        unsigned pending_weak_ref:1;
        unsigned has_async_transaction:1;
        unsigned accept_fds:1;
        unsigned min_priority:8;
        struct list_head async_todo;
};

struct binder_ref_death {
        struct binder_work work;
        void __user *cookie;
};

struct binder_ref {
        /* Lookups needed: */
        /*   node + proc => ref (transaction) */
        /*   desc + proc => ref (transaction, inc/dec ref) */
        /*   node => refs + procs (proc exit) */
        int debug_id;
        struct rb_node rb_node_desc;
        struct rb_node rb_node_node;
        struct hlist_node node_entry;
        struct binder_proc *proc;
        struct binder_node *node;
        uint32_t desc;
        int strong;
        int weak;
        struct binder_ref_death *death;
};

struct binder_buffer {
        struct list_head entry; /* free and allocated entries by address */
        struct rb_node rb_node; /* free entry by size or allocated entry */
                                /* by address */
        unsigned free:1;
        unsigned allow_user_free:1;
        unsigned async_transaction:1;
        unsigned debug_id:29;

        struct binder_transaction *transaction;

        struct binder_node *target_node;
        size_t data_size;
        size_t offsets_size;
        uint8_t data[0];
};

enum binder_deferred_state {
        BINDER_DEFERRED_PUT_FILES    = 0x01,
        BINDER_DEFERRED_FLUSH        = 0x02,
        BINDER_DEFERRED_RELEASE      = 0x04,
};

struct binder_proc {
        struct hlist_node proc_node;
        struct rb_root threads;
        struct rb_root nodes;
        struct rb_root refs_by_desc;
        struct rb_root refs_by_node;
        int pid;
        struct vm_area_struct *vma;
        struct mm_struct *vma_vm_mm;
        struct task_struct *tsk;
        struct files_struct *files;
        struct hlist_node deferred_work_node;
        int deferred_work;
        void *buffer;
        ptrdiff_t user_buffer_offset;

        struct list_head buffers;
        struct rb_root free_buffers;
        struct rb_root allocated_buffers;
        size_t free_async_space;

        struct page **pages;
        size_t buffer_size;
        uint32_t buffer_free;
        struct list_head todo;
        wait_queue_head_t wait;
        struct binder_stats stats;
        struct list_head delivered_death;
        int max_threads;
        int requested_threads;
        int requested_threads_started;
        int ready_threads;
        long default_priority;
        struct dentry *debugfs_entry;
};

enum {
        BINDER_LOOPER_STATE_REGISTERED  = 0x01,
        BINDER_LOOPER_STATE_ENTERED     = 0x02,
        BINDER_LOOPER_STATE_EXITED      = 0x04,
        BINDER_LOOPER_STATE_INVALID     = 0x08,
        BINDER_LOOPER_STATE_WAITING     = 0x10,
        BINDER_LOOPER_STATE_NEED_RETURN = 0x20
};

struct binder_thread {
        struct binder_proc *proc;
        struct rb_node rb_node;
        int pid;
        int looper;
        struct binder_transaction *transaction_stack;
        struct list_head todo;
        uint32_t return_error; /* Write failed, return error code in read buf */
        uint32_t return_error2; /* Write failed, return error code in read */
                /* buffer. Used when sending a reply to a dead process that */
                /* we are also waiting on */
        wait_queue_head_t wait;
        struct binder_stats stats;
};

struct binder_transaction {
        int debug_id;
        struct binder_work work;
        struct binder_thread *from;
        struct binder_transaction *from_parent;
        struct binder_proc *to_proc;
        struct binder_thread *to_thread;
        struct binder_transaction *to_parent;
        unsigned need_reply:1;
        /* unsigned is_dead:1; */       /* not used at the moment */

        struct binder_buffer *buffer;
        unsigned int    code;
        unsigned int    flags;
        long    priority;
        long    saved_priority;
        kuid_t  sender_euid;
};

static void
binder_defer_work(struct binder_proc *proc, enum binder_deferred_state defer);

static int task_get_unused_fd_flags(struct binder_proc *proc, int flags)
{
        struct files_struct *files = proc->files;
        unsigned long rlim_cur;
        unsigned long irqs;

        if (files == NULL)
                return -ESRCH;

        if (!lock_task_sighand(proc->tsk, &irqs))
                return -EMFILE;

        rlim_cur = task_rlimit(proc->tsk, RLIMIT_NOFILE);
        unlock_task_sighand(proc->tsk, &irqs);

        return __alloc_fd(files, 0, rlim_cur, flags);
}

/*
 * copied from fd_install
 */
static void task_fd_install(
        struct binder_proc *proc, unsigned int fd, struct file *file)
{
        if (proc->files)
                __fd_install(proc->files, fd, file);
}

/*
 * copied from sys_close
 */
static long task_close_fd(struct binder_proc *proc, unsigned int fd)
{
        int retval;

        if (proc->files == NULL)
                return -ESRCH;

        retval = __close_fd(proc->files, fd);
        /* can't restart close syscall because file table entry was cleared */
        if (unlikely(retval == -ERESTARTSYS ||
                     retval == -ERESTARTNOINTR ||
                     retval == -ERESTARTNOHAND ||
                     retval == -ERESTART_RESTARTBLOCK))
                retval = -EINTR;

        return retval;
}

static inline void binder_lock(const char *tag)
{
        trace_binder_lock(tag);
        mutex_lock(&binder_main_lock);
        trace_binder_locked(tag);
}

static inline void binder_unlock(const char *tag)
{
        trace_binder_unlock(tag);
        mutex_unlock(&binder_main_lock);
}

static void binder_set_nice(long nice)
{
        long min_nice;
        if (can_nice(current, nice)) {
                set_user_nice(current, nice);
                return;
        }
        min_nice = 20 - current->signal->rlim[RLIMIT_NICE].rlim_cur;
        binder_debug(BINDER_DEBUG_PRIORITY_CAP,
                     "%d: nice value %ld not allowed use %ld instead\n",
                      current->pid, nice, min_nice);
        set_user_nice(current, min_nice);
        if (min_nice < 20)
                return;
        binder_user_error("%d RLIMIT_NICE not set\n", current->pid);
}

static size_t binder_buffer_size(struct binder_proc *proc,
                                 struct binder_buffer *buffer)
{
        if (list_is_last(&buffer->entry, &proc->buffers))
                return proc->buffer + proc->buffer_size - (void *)buffer->data;
        else
                return (size_t)list_entry(buffer->entry.next,
                        struct binder_buffer, entry) - (size_t)buffer->data;
}

static void binder_insert_free_buffer(struct binder_proc *proc,
                                      struct binder_buffer *new_buffer)
{
        struct rb_node **p = &proc->free_buffers.rb_node;
        struct rb_node *parent = NULL;
        struct binder_buffer *buffer;
        size_t buffer_size;
        size_t new_buffer_size;

        BUG_ON(!new_buffer->free);

        new_buffer_size = binder_buffer_size(proc, new_buffer);

        binder_debug(BINDER_DEBUG_BUFFER_ALLOC,
                     "%d: add free buffer, size %zd, at %p\n",
                      proc->pid, new_buffer_size, new_buffer);

        while (*p) {
                parent = *p;
                buffer = rb_entry(parent, struct binder_buffer, rb_node);
                BUG_ON(!buffer->free);

                buffer_size = binder_buffer_size(proc, buffer);

                if (new_buffer_size < buffer_size)
                        p = &parent->rb_left;
                else
                        p = &parent->rb_right;
        }
        rb_link_node(&new_buffer->rb_node, parent, p);
        rb_insert_color(&new_buffer->rb_node, &proc->free_buffers);
}

static void binder_insert_allocated_buffer(struct binder_proc *proc,
                                           struct binder_buffer *new_buffer)
{
        struct rb_node **p = &proc->allocated_buffers.rb_node;
        struct rb_node *parent = NULL;
        struct binder_buffer *buffer;

        BUG_ON(new_buffer->free);

        while (*p) {
                parent = *p;
                buffer = rb_entry(parent, struct binder_buffer, rb_node);
                BUG_ON(buffer->free);

                if (new_buffer < buffer)
                        p = &parent->rb_left;
                else if (new_buffer > buffer)
                        p = &parent->rb_right;
                else
                        BUG();
        }
        rb_link_node(&new_buffer->rb_node, parent, p);
        rb_insert_color(&new_buffer->rb_node, &proc->allocated_buffers);
}

static struct binder_buffer *binder_buffer_lookup(struct binder_proc *proc,
                                                  void __user *user_ptr)
{
        struct rb_node *n = proc->allocated_buffers.rb_node;
        struct binder_buffer *buffer;
        struct binder_buffer *kern_ptr;

        kern_ptr = user_ptr - proc->user_buffer_offset
                - offsetof(struct binder_buffer, data);

        while (n) {
                buffer = rb_entry(n, struct binder_buffer, rb_node);
                BUG_ON(buffer->free);

                if (kern_ptr < buffer)
                        n = n->rb_left;
                else if (kern_ptr > buffer)
                        n = n->rb_right;
                else
                        return buffer;
        }
        return NULL;
}

static int binder_update_page_range(struct binder_proc *proc, int allocate,
                                    void *start, void *end,
                                    struct vm_area_struct *vma)
{
        void *page_addr;
        unsigned long user_page_addr;
        struct vm_struct tmp_area;
        struct page **page;
        struct mm_struct *mm;

        binder_debug(BINDER_DEBUG_BUFFER_ALLOC,
                     "%d: %s pages %p-%p\n", proc->pid,
                     allocate ? "allocate" : "free", start, end);

        if (end <= start)
                return 0;

        trace_binder_update_page_range(proc, allocate, start, end);

        if (vma)
                mm = NULL;
        else
                mm = get_task_mm(proc->tsk);

        if (mm) {
                down_write(&mm->mmap_sem);
                vma = proc->vma;
                if (vma && mm != proc->vma_vm_mm) {
                        pr_err("%d: vma mm and task mm mismatch\n",
                                proc->pid);
                        vma = NULL;
                }
        }

        if (allocate == 0)
                goto free_range;

        if (vma == NULL) {
                pr_err("%d: binder_alloc_buf failed to map pages in userspace, no vma\n",
                        proc->pid);
                goto err_no_vma;
        }

        for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
                int ret;
                struct page **page_array_ptr;
                page = &proc->pages[(page_addr - proc->buffer) / PAGE_SIZE];

                BUG_ON(*page);
                *page = alloc_page(GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO);
                if (*page == NULL) {
                        pr_err("%d: binder_alloc_buf failed for page at %p\n",
                                proc->pid, page_addr);
                        goto err_alloc_page_failed;
                }
                tmp_area.addr = page_addr;
                tmp_area.size = PAGE_SIZE + PAGE_SIZE /* guard page? */;
                page_array_ptr = page;
                ret = map_vm_area(&tmp_area, PAGE_KERNEL, &page_array_ptr);
                if (ret) {
                        pr_err("%d: binder_alloc_buf failed to map page at %p in kernel\n",
                               proc->pid, page_addr);
                        goto err_map_kernel_failed;
                }
                user_page_addr =
                        (uintptr_t)page_addr + proc->user_buffer_offset;
                ret = vm_insert_page(vma, user_page_addr, page[0]);
                if (ret) {
                        pr_err("%d: binder_alloc_buf failed to map page at %lx in userspace\n",
                               proc->pid, user_page_addr);
                        goto err_vm_insert_page_failed;
                }
                /* vm_insert_page does not seem to increment the refcount */
        }
        if (mm) {
                up_write(&mm->mmap_sem);
                mmput(mm);
        }
        return 0;

free_range:
        for (page_addr = end - PAGE_SIZE; page_addr >= start;
             page_addr -= PAGE_SIZE) {
                page = &proc->pages[(page_addr - proc->buffer) / PAGE_SIZE];
                if (vma)
                        zap_page_range(vma, (uintptr_t)page_addr +
                                proc->user_buffer_offset, PAGE_SIZE, NULL);
err_vm_insert_page_failed:
                unmap_kernel_range((unsigned long)page_addr, PAGE_SIZE);
err_map_kernel_failed:
                __free_page(*page);
                *page = NULL;
err_alloc_page_failed:
                ;
        }
err_no_vma:
        if (mm) {
                up_write(&mm->mmap_sem);
                mmput(mm);
        }
        return -ENOMEM;
}

static struct binder_buffer *binder_alloc_buf(struct binder_proc *proc,
                                              size_t data_size,
                                              size_t offsets_size, int is_async)
{
        struct rb_node *n = proc->free_buffers.rb_node;
        struct binder_buffer *buffer;
        size_t buffer_size;
        struct rb_node *best_fit = NULL;
        void *has_page_addr;
        void *end_page_addr;
        size_t size;

        if (proc->vma == NULL) {
                pr_err("%d: binder_alloc_buf, no vma\n",
                       proc->pid);
                return NULL;
        }

        size = ALIGN(data_size, sizeof(void *)) +
                ALIGN(offsets_size, sizeof(void *));

        if (size < data_size || size < offsets_size) {
                binder_user_error("%d: got transaction with invalid size %zd-%zd\n",
                                proc->pid, data_size, offsets_size);
                return NULL;
        }

        if (is_async &&
            proc->free_async_space < size + sizeof(struct binder_buffer)) {
                binder_debug(BINDER_DEBUG_BUFFER_ALLOC,
                             "%d: binder_alloc_buf size %zd failed, no async space left\n",
                              proc->pid, size);
                return NULL;
        }

        while (n) {
                buffer = rb_entry(n, struct binder_buffer, rb_node);
                BUG_ON(!buffer->free);
                buffer_size = binder_buffer_size(proc, buffer);

                if (size < buffer_size) {
                        best_fit = n;
                        n = n->rb_left;
                } else if (size > buffer_size)
                        n = n->rb_right;
                else {
                        best_fit = n;
                        break;
                }
        }
        if (best_fit == NULL) {
                pr_err("%d: binder_alloc_buf size %zd failed, no address space\n",
                        proc->pid, size);
                return NULL;
        }
        if (n == NULL) {
                buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
                buffer_size = binder_buffer_size(proc, buffer);
        }

        binder_debug(BINDER_DEBUG_BUFFER_ALLOC,
                     "%d: binder_alloc_buf size %zd got buffer %p size %zd\n",
                      proc->pid, size, buffer, buffer_size);

        has_page_addr =
                (void *)(((uintptr_t)buffer->data + buffer_size) & PAGE_MASK);
        if (n == NULL) {
                if (size + sizeof(struct binder_buffer) + 4 >= buffer_size)
                        buffer_size = size; /* no room for other buffers */
                else
                        buffer_size = size + sizeof(struct binder_buffer);
        }
        end_page_addr =
                (void *)PAGE_ALIGN((uintptr_t)buffer->data + buffer_size);
        if (end_page_addr > has_page_addr)
                end_page_addr = has_page_addr;
        if (binder_update_page_range(proc, 1,
            (void *)PAGE_ALIGN((uintptr_t)buffer->data), end_page_addr, NULL))
                return NULL;

        rb_erase(best_fit, &proc->free_buffers);
        buffer->free = 0;
        binder_insert_allocated_buffer(proc, buffer);
        if (buffer_size != size) {
                struct binder_buffer *new_buffer = (void *)buffer->data + size;
                list_add(&new_buffer->entry, &buffer->entry);
                new_buffer->free = 1;
                binder_insert_free_buffer(proc, new_buffer);
        }
        binder_debug(BINDER_DEBUG_BUFFER_ALLOC,
                     "%d: binder_alloc_buf size %zd got %p\n",
                      proc->pid, size, buffer);
        buffer->data_size = data_size;
        buffer->offsets_size = offsets_size;
        buffer->async_transaction = is_async;
        if (is_async) {
                proc->free_async_space -= size + sizeof(struct binder_buffer);
                binder_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
                             "%d: binder_alloc_buf size %zd async free %zd\n",
                              proc->pid, size, proc->free_async_space);
        }

        return buffer;
}

static void *buffer_start_page(struct binder_buffer *buffer)
{
        return (void *)((uintptr_t)buffer & PAGE_MASK);
}

static void *buffer_end_page(struct binder_buffer *buffer)
{
        return (void *)(((uintptr_t)(buffer + 1) - 1) & PAGE_MASK);
}

static void binder_delete_free_buffer(struct binder_proc *proc,
                                      struct binder_buffer *buffer)
{
        struct binder_buffer *prev, *next = NULL;
        int free_page_end = 1;
        int free_page_start = 1;

        BUG_ON(proc->buffers.next == &buffer->entry);
        prev = list_entry(buffer->entry.prev, struct binder_buffer, entry);
        BUG_ON(!prev->free);
        if (buffer_end_page(prev) == buffer_start_page(buffer)) {
                free_page_start = 0;
                if (buffer_end_page(prev) == buffer_end_page(buffer))
                        free_page_end = 0;
                binder_debug(BINDER_DEBUG_BUFFER_ALLOC,
                             "%d: merge free, buffer %p share page with %p\n",
                              proc->pid, buffer, prev);
        }

        if (!list_is_last(&buffer->entry, &proc->buffers)) {
                next = list_entry(buffer->entry.next,
                                  struct binder_buffer, entry);
                if (buffer_start_page(next) == buffer_end_page(buffer)) {
                        free_page_end = 0;
                        if (buffer_start_page(next) ==
                            buffer_start_page(buffer))
                                free_page_start = 0;
                        binder_debug(BINDER_DEBUG_BUFFER_ALLOC,
                                     "%d: merge free, buffer %p share page with %p\n",
                                      proc->pid, buffer, prev);
                }
        }
        list_del(&buffer->entry);
        if (free_page_start || free_page_end) {
                binder_debug(BINDER_DEBUG_BUFFER_ALLOC,
                             "%d: merge free, buffer %p do not share page%s%s with %p or %p\n",
                             proc->pid, buffer, free_page_start ? "" : " end",
                             free_page_end ? "" : " start", prev, next);
                binder_update_page_range(proc, 0, free_page_start ?
                        buffer_start_page(buffer) : buffer_end_page(buffer),
                        (free_page_end ? buffer_end_page(buffer) :
                        buffer_start_page(buffer)) + PAGE_SIZE, NULL);
        }
}

static void binder_free_buf(struct binder_proc *proc,
                            struct binder_buffer *buffer)
{
        size_t size, buffer_size;

        buffer_size = binder_buffer_size(proc, buffer);

        size = ALIGN(buffer->data_size, sizeof(void *)) +
                ALIGN(buffer->offsets_size, sizeof(void *));

        binder_debug(BINDER_DEBUG_BUFFER_ALLOC,
                     "%d: binder_free_buf %p size %zd buffer_size %zd\n",
                      proc->pid, buffer, size, buffer_size);

        BUG_ON(buffer->free);
        BUG_ON(size > buffer_size);
        BUG_ON(buffer->transaction != NULL);
        BUG_ON((void *)buffer < proc->buffer);
        BUG_ON((void *)buffer > proc->buffer + proc->buffer_size);

        if (buffer->async_transaction) {
                proc->free_async_space += size + sizeof(struct binder_buffer);

                binder_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
                             "%d: binder_free_buf size %zd async free %zd\n",
                              proc->pid, size, proc->free_async_space);
        }

        binder_update_page_range(proc, 0,
                (void *)PAGE_ALIGN((uintptr_t)buffer->data),
                (void *)(((uintptr_t)buffer->data + buffer_size) & PAGE_MASK),
                NULL);
        rb_erase(&buffer->rb_node, &proc->allocated_buffers);
        buffer->free = 1;
        if (!list_is_last(&buffer->entry, &proc->buffers)) {
                struct binder_buffer *next = list_entry(buffer->entry.next,
                                                struct binder_buffer, entry);
                if (next->free) {
                        rb_erase(&next->rb_node, &proc->free_buffers);
                        binder_delete_free_buffer(proc, next);
                }
        }
        if (proc->buffers.next != &buffer->entry) {
                struct binder_buffer *prev = list_entry(buffer->entry.prev,
                                                struct binder_buffer, entry);
                if (prev->free) {
                        binder_delete_free_buffer(proc, buffer);
                        rb_erase(&prev->rb_node, &proc->free_buffers);
                        buffer = prev;
                }
        }
        binder_insert_free_buffer(proc, buffer);
}

static struct binder_node *binder_get_node(struct binder_proc *proc,
                                           void __user *ptr)
{
        struct rb_node *n = proc->nodes.rb_node;
        struct binder_node *node;

        while (n) {
                node = rb_entry(n, struct binder_node, rb_node);

                if (ptr < node->ptr)
                        n = n->rb_left;
                else if (ptr > node->ptr)
                        n = n->rb_right;
                else
                        return node;
        }
        return NULL;
}

static struct binder_node *binder_new_node(struct binder_proc *proc,
                                           void __user *ptr,
                                           void __user *cookie)
{
        struct rb_node **p = &proc->nodes.rb_node;
        struct rb_node *parent = NULL;
        struct binder_node *node;

        while (*p) {
                parent = *p;
                node = rb_entry(parent, struct binder_node, rb_node);

                if (ptr < node->ptr)
                        p = &(*p)->rb_left;
                else if (ptr > node->ptr)
                        p = &(*p)->rb_right;
                else
                        return NULL;
        }

        node = kzalloc(sizeof(*node), GFP_KERNEL);
        if (node == NULL)
                return NULL;
        binder_stats_created(BINDER_STAT_NODE);
        rb_link_node(&node->rb_node, parent, p);
        rb_insert_color(&node->rb_node, &proc->nodes);
        node->debug_id = ++binder_last_id;
        node->proc = proc;
        node->ptr = ptr;
        node->cookie = cookie;
        node->work.type = BINDER_WORK_NODE;
        INIT_LIST_HEAD(&node->work.entry);
        INIT_LIST_HEAD(&node->async_todo);
        binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                     "%d:%d node %d u%p c%p created\n",
                     proc->pid, current->pid, node->debug_id,
                     node->ptr, node->cookie);
        return node;
}

static int binder_inc_node(struct binder_node *node, int strong, int internal,
                           struct list_head *target_list)
{
        if (strong) {
                if (internal) {
                        if (target_list == NULL &&
                            node->internal_strong_refs == 0 &&
                            !(node == binder_context_mgr_node &&
                            node->has_strong_ref)) {
                                pr_err("invalid inc strong node for %d\n",
                                        node->debug_id);
                                return -EINVAL;
                        }
                        node->internal_strong_refs++;
                } else
                        node->local_strong_refs++;
                if (!node->has_strong_ref && target_list) {
                        list_del_init(&node->work.entry);
                        list_add_tail(&node->work.entry, target_list);
                }
        } else {
                if (!internal)
                        node->local_weak_refs++;
                if (!node->has_weak_ref && list_empty(&node->work.entry)) {
                        if (target_list == NULL) {
                                pr_err("invalid inc weak node for %d\n",
                                        node->debug_id);
                                return -EINVAL;
                        }
                        list_add_tail(&node->work.entry, target_list);
                }
        }
        return 0;
}

static int binder_dec_node(struct binder_node *node, int strong, int internal)
{
        if (strong) {
                if (internal)
                        node->internal_strong_refs--;
                else
                        node->local_strong_refs--;
                if (node->local_strong_refs || node->internal_strong_refs)
                        return 0;
        } else {
                if (!internal)
                        node->local_weak_refs--;
                if (node->local_weak_refs || !hlist_empty(&node->refs))
                        return 0;
        }
        if (node->proc && (node->has_strong_ref || node->has_weak_ref)) {
                if (list_empty(&node->work.entry)) {
                        list_add_tail(&node->work.entry, &node->proc->todo);
                        wake_up_interruptible(&node->proc->wait);
                }
        } else {
                if (hlist_empty(&node->refs) && !node->local_strong_refs &&
                    !node->local_weak_refs) {
                        list_del_init(&node->work.entry);
                        if (node->proc) {
                                rb_erase(&node->rb_node, &node->proc->nodes);
                                binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                                             "refless node %d deleted\n",
                                             node->debug_id);
                        } else {
                                hlist_del(&node->dead_node);
                                binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                                             "dead node %d deleted\n",
                                             node->debug_id);
                        }
                        kfree(node);
                        binder_stats_deleted(BINDER_STAT_NODE);
                }
        }

        return 0;
}


static struct binder_ref *binder_get_ref(struct binder_proc *proc,
                                         uint32_t desc)
{
        struct rb_node *n = proc->refs_by_desc.rb_node;
        struct binder_ref *ref;

        while (n) {
                ref = rb_entry(n, struct binder_ref, rb_node_desc);

                if (desc < ref->desc)
                        n = n->rb_left;
                else if (desc > ref->desc)
                        n = n->rb_right;
                else
                        return ref;
        }
        return NULL;
}

static struct binder_ref *binder_get_ref_for_node(struct binder_proc *proc,
                                                  struct binder_node *node)
{
        struct rb_node *n;
        struct rb_node **p = &proc->refs_by_node.rb_node;
        struct rb_node *parent = NULL;
        struct binder_ref *ref, *new_ref;

        while (*p) {
                parent = *p;
                ref = rb_entry(parent, struct binder_ref, rb_node_node);

                if (node < ref->node)
                        p = &(*p)->rb_left;
                else if (node > ref->node)
                        p = &(*p)->rb_right;
                else
                        return ref;
        }
        new_ref = kzalloc(sizeof(*ref), GFP_KERNEL);
        if (new_ref == NULL)
                return NULL;
        binder_stats_created(BINDER_STAT_REF);
        new_ref->debug_id = ++binder_last_id;
        new_ref->proc = proc;
        new_ref->node = node;
        rb_link_node(&new_ref->rb_node_node, parent, p);
        rb_insert_color(&new_ref->rb_node_node, &proc->refs_by_node);

        new_ref->desc = (node == binder_context_mgr_node) ? 0 : 1;
        for (n = rb_first(&proc->refs_by_desc); n != NULL; n = rb_next(n)) {
                ref = rb_entry(n, struct binder_ref, rb_node_desc);
                if (ref->desc > new_ref->desc)
                        break;
                new_ref->desc = ref->desc + 1;
        }

        p = &proc->refs_by_desc.rb_node;
        while (*p) {
                parent = *p;
                ref = rb_entry(parent, struct binder_ref, rb_node_desc);

                if (new_ref->desc < ref->desc)
                        p = &(*p)->rb_left;
                else if (new_ref->desc > ref->desc)
                        p = &(*p)->rb_right;
                else
                        BUG();
        }
        rb_link_node(&new_ref->rb_node_desc, parent, p);
        rb_insert_color(&new_ref->rb_node_desc, &proc->refs_by_desc);
        if (node) {
                hlist_add_head(&new_ref->node_entry, &node->refs);

                binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                             "%d new ref %d desc %d for node %d\n",
                              proc->pid, new_ref->debug_id, new_ref->desc,
                              node->debug_id);
        } else {
                binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                             "%d new ref %d desc %d for dead node\n",
                              proc->pid, new_ref->debug_id, new_ref->desc);
        }
        return new_ref;
}

static void binder_delete_ref(struct binder_ref *ref)
{
        binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                     "%d delete ref %d desc %d for node %d\n",
                      ref->proc->pid, ref->debug_id, ref->desc,
                      ref->node->debug_id);

        rb_erase(&ref->rb_node_desc, &ref->proc->refs_by_desc);
        rb_erase(&ref->rb_node_node, &ref->proc->refs_by_node);
        if (ref->strong)
                binder_dec_node(ref->node, 1, 1);
        hlist_del(&ref->node_entry);
        binder_dec_node(ref->node, 0, 1);
        if (ref->death) {
                binder_debug(BINDER_DEBUG_DEAD_BINDER,
                             "%d delete ref %d desc %d has death notification\n",
                              ref->proc->pid, ref->debug_id, ref->desc);
                list_del(&ref->death->work.entry);
                kfree(ref->death);
                binder_stats_deleted(BINDER_STAT_DEATH);
        }
        kfree(ref);
        binder_stats_deleted(BINDER_STAT_REF);
}

static int binder_inc_ref(struct binder_ref *ref, int strong,
                          struct list_head *target_list)
{
        int ret;
        if (strong) {
                if (ref->strong == 0) {
                        ret = binder_inc_node(ref->node, 1, 1, target_list);
                        if (ret)
                                return ret;
                }
                ref->strong++;
        } else {
                if (ref->weak == 0) {
                        ret = binder_inc_node(ref->node, 0, 1, target_list);
                        if (ret)
                                return ret;
                }
                ref->weak++;
        }
        return 0;
}


static int binder_dec_ref(struct binder_ref *ref, int strong)
{
        if (strong) {
                if (ref->strong == 0) {
                        binder_user_error("%d invalid dec strong, ref %d desc %d s %d w %d\n",
                                          ref->proc->pid, ref->debug_id,
                                          ref->desc, ref->strong, ref->weak);
                        return -EINVAL;
                }
                ref->strong--;
                if (ref->strong == 0) {
                        int ret;
                        ret = binder_dec_node(ref->node, strong, 1);
                        if (ret)
                                return ret;
                }
        } else {
                if (ref->weak == 0) {
                        binder_user_error("%d invalid dec weak, ref %d desc %d s %d w %d\n",
                                          ref->proc->pid, ref->debug_id,
                                          ref->desc, ref->strong, ref->weak);
                        return -EINVAL;
                }
                ref->weak--;
        }
        if (ref->strong == 0 && ref->weak == 0)
                binder_delete_ref(ref);
        return 0;
}

static void binder_pop_transaction(struct binder_thread *target_thread,
                                   struct binder_transaction *t)
{
        if (target_thread) {
                BUG_ON(target_thread->transaction_stack != t);
                BUG_ON(target_thread->transaction_stack->from != target_thread);
                target_thread->transaction_stack =
                        target_thread->transaction_stack->from_parent;
                t->from = NULL;
        }
        t->need_reply = 0;
        if (t->buffer)
                t->buffer->transaction = NULL;
        kfree(t);
        binder_stats_deleted(BINDER_STAT_TRANSACTION);
}

static void binder_send_failed_reply(struct binder_transaction *t,
                                     uint32_t error_code)
{
        struct binder_thread *target_thread;
        BUG_ON(t->flags & TF_ONE_WAY);
        while (1) {
                target_thread = t->from;
                if (target_thread) {
                        if (target_thread->return_error != BR_OK &&
                           target_thread->return_error2 == BR_OK) {
                                target_thread->return_error2 =
                                        target_thread->return_error;
                                target_thread->return_error = BR_OK;
                        }
                        if (target_thread->return_error == BR_OK) {
                                binder_debug(BINDER_DEBUG_FAILED_TRANSACTION,
                                             "send failed reply for transaction %d to %d:%d\n",
                                              t->debug_id, target_thread->proc->pid,
                                              target_thread->pid);

                                binder_pop_transaction(target_thread, t);
                                target_thread->return_error = error_code;
                                wake_up_interruptible(&target_thread->wait);
                        } else {
                                pr_err("reply failed, target thread, %d:%d, has error code %d already\n",
                                        target_thread->proc->pid,
                                        target_thread->pid,
                                        target_thread->return_error);
                        }
                        return;
                } else {
                        struct binder_transaction *next = t->from_parent;

                        binder_debug(BINDER_DEBUG_FAILED_TRANSACTION,
                                     "send failed reply for transaction %d, target dead\n",
                                     t->debug_id);

                        binder_pop_transaction(target_thread, t);
                        if (next == NULL) {
                                binder_debug(BINDER_DEBUG_DEAD_BINDER,
                                             "reply failed, no target thread at root\n");
                                return;
                        }
                        t = next;
                        binder_debug(BINDER_DEBUG_DEAD_BINDER,
                                     "reply failed, no target thread -- retry %d\n",
                                      t->debug_id);
                }
        }
}

static void binder_transaction_buffer_release(struct binder_proc *proc,
                                              struct binder_buffer *buffer,
                                              size_t *failed_at)
{
        size_t *offp, *off_end;
        int debug_id = buffer->debug_id;

        binder_debug(BINDER_DEBUG_TRANSACTION,
                     "%d buffer release %d, size %zd-%zd, failed at %p\n",
                     proc->pid, buffer->debug_id,
                     buffer->data_size, buffer->offsets_size, failed_at);

        if (buffer->target_node)
                binder_dec_node(buffer->target_node, 1, 0);

        offp = (size_t *)(buffer->data + ALIGN(buffer->data_size, sizeof(void *)));
        if (failed_at)
                off_end = failed_at;
        else
                off_end = (void *)offp + buffer->offsets_size;
        for (; offp < off_end; offp++) {
                struct flat_binder_object *fp;
                if (*offp > buffer->data_size - sizeof(*fp) ||
                    buffer->data_size < sizeof(*fp) ||
                    !IS_ALIGNED(*offp, sizeof(void *))) {
                        pr_err("transaction release %d bad offset %zd, size %zd\n",
                         debug_id, *offp, buffer->data_size);
                        continue;
                }
                fp = (struct flat_binder_object *)(buffer->data + *offp);
                switch (fp->type) {
                case BINDER_TYPE_BINDER:
                case BINDER_TYPE_WEAK_BINDER: {
                        struct binder_node *node = binder_get_node(proc, fp->binder);
                        if (node == NULL) {
                                pr_err("transaction release %d bad node %p\n",
                                        debug_id, fp->binder);
                                break;
                        }
                        binder_debug(BINDER_DEBUG_TRANSACTION,
                                     "        node %d u%p\n",
                                     node->debug_id, node->ptr);
                        binder_dec_node(node, fp->type == BINDER_TYPE_BINDER, 0);
                } break;
                case BINDER_TYPE_HANDLE:
                case BINDER_TYPE_WEAK_HANDLE: {
                        struct binder_ref *ref = binder_get_ref(proc, fp->handle);
                        if (ref == NULL) {
                                pr_err("transaction release %d bad handle %ld\n",
                                 debug_id, fp->handle);
                                break;
                        }
                        binder_debug(BINDER_DEBUG_TRANSACTION,
                                     "        ref %d desc %d (node %d)\n",
                                     ref->debug_id, ref->desc, ref->node->debug_id);
                        binder_dec_ref(ref, fp->type == BINDER_TYPE_HANDLE);
                } break;

                case BINDER_TYPE_FD:
                        binder_debug(BINDER_DEBUG_TRANSACTION,
                                     "        fd %ld\n", fp->handle);
                        if (failed_at)
                                task_close_fd(proc, fp->handle);
                        break;

                default:
                        pr_err("transaction release %d bad object type %lx\n",
                                debug_id, fp->type);
                        break;
                }
        }
}

static void binder_transaction(struct binder_proc *proc,
                               struct binder_thread *thread,
                               struct binder_transaction_data *tr, int reply)
{
        struct binder_transaction *t;
        struct binder_work *tcomplete;
        size_t *offp, *off_end;
        struct binder_proc *target_proc;
        struct binder_thread *target_thread = NULL;
        struct binder_node *target_node = NULL;
        struct list_head *target_list;
        wait_queue_head_t *target_wait;
        struct binder_transaction *in_reply_to = NULL;
        struct binder_transaction_log_entry *e;
        uint32_t return_error;

        e = binder_transaction_log_add(&binder_transaction_log);
        e->call_type = reply ? 2 : !!(tr->flags & TF_ONE_WAY);
        e->from_proc = proc->pid;
        e->from_thread = thread->pid;
        e->target_handle = tr->target.handle;
        e->data_size = tr->data_size;
        e->offsets_size = tr->offsets_size;

        if (reply) {
                in_reply_to = thread->transaction_stack;
                if (in_reply_to == NULL) {
                        binder_user_error("%d:%d got reply transaction with no transaction stack\n",
                                          proc->pid, thread->pid);
                        return_error = BR_FAILED_REPLY;
                        goto err_empty_call_stack;
                }
                binder_set_nice(in_reply_to->saved_priority);
                if (in_reply_to->to_thread != thread) {
                        binder_user_error("%d:%d got reply transaction with bad transaction stack, transaction %d has target %d:%d\n",
                                proc->pid, thread->pid, in_reply_to->debug_id,
                                in_reply_to->to_proc ?
                                in_reply_to->to_proc->pid : 0,
                                in_reply_to->to_thread ?
                                in_reply_to->to_thread->pid : 0);
                        return_error = BR_FAILED_REPLY;
                        in_reply_to = NULL;
                        goto err_bad_call_stack;
                }
                thread->transaction_stack = in_reply_to->to_parent;
                target_thread = in_reply_to->from;
                if (target_thread == NULL) {
                        return_error = BR_DEAD_REPLY;
                        goto err_dead_binder;
                }
                if (target_thread->transaction_stack != in_reply_to) {
                        binder_user_error("%d:%d got reply transaction with bad target transaction stack %d, expected %d\n",
                                proc->pid, thread->pid,
                                target_thread->transaction_stack ?
                                target_thread->transaction_stack->debug_id : 0,
                                in_reply_to->debug_id);
                        return_error = BR_FAILED_REPLY;
                        in_reply_to = NULL;
                        target_thread = NULL;
                        goto err_dead_binder;
                }
                target_proc = target_thread->proc;
        } else {
                if (tr->target.handle) {
                        struct binder_ref *ref;
                        ref = binder_get_ref(proc, tr->target.handle);
                        if (ref == NULL) {
                                binder_user_error("%d:%d got transaction to invalid handle\n",
                                        proc->pid, thread->pid);
                                return_error = BR_FAILED_REPLY;
                                goto err_invalid_target_handle;
                        }
                        target_node = ref->node;
                } else {
                        target_node = binder_context_mgr_node;
                        if (target_node == NULL) {
                                return_error = BR_DEAD_REPLY;
                                goto err_no_context_mgr_node;
                        }
                }
                e->to_node = target_node->debug_id;
                target_proc = target_node->proc;
                if (target_proc == NULL) {
                        return_error = BR_DEAD_REPLY;
                        goto err_dead_binder;
                }
                if (!(tr->flags & TF_ONE_WAY) && thread->transaction_stack) {
                        struct binder_transaction *tmp;
                        tmp = thread->transaction_stack;
                        if (tmp->to_thread != thread) {
                                binder_user_error("%d:%d got new transaction with bad transaction stack, transaction %d has target %d:%d\n",
                                        proc->pid, thread->pid, tmp->debug_id,
                                        tmp->to_proc ? tmp->to_proc->pid : 0,
                                        tmp->to_thread ?
                                        tmp->to_thread->pid : 0);
                                return_error = BR_FAILED_REPLY;
                                goto err_bad_call_stack;
                        }
                        while (tmp) {
                                if (tmp->from && tmp->from->proc == target_proc)
                                        target_thread = tmp->from;
                                tmp = tmp->from_parent;
                        }
                }
        }
        if (target_thread) {
                e->to_thread = target_thread->pid;
                target_list = &target_thread->todo;
                target_wait = &target_thread->wait;
        } else {
                target_list = &target_proc->todo;
                target_wait = &target_proc->wait;
        }
        e->to_proc = target_proc->pid;

        /* TODO: reuse incoming transaction for reply */
        t = kzalloc(sizeof(*t), GFP_KERNEL);
        if (t == NULL) {
                return_error = BR_FAILED_REPLY;
                goto err_alloc_t_failed;
        }
        binder_stats_created(BINDER_STAT_TRANSACTION);

        tcomplete = kzalloc(sizeof(*tcomplete), GFP_KERNEL);
        if (tcomplete == NULL) {
                return_error = BR_FAILED_REPLY;
                goto err_alloc_tcomplete_failed;
        }
        binder_stats_created(BINDER_STAT_TRANSACTION_COMPLETE);

        t->debug_id = ++binder_last_id;
        e->debug_id = t->debug_id;

        if (reply)
                binder_debug(BINDER_DEBUG_TRANSACTION,
                             "%d:%d BC_REPLY %d -> %d:%d, data %p-%p size %zd-%zd\n",
                             proc->pid, thread->pid, t->debug_id,
                             target_proc->pid, target_thread->pid,
                             tr->data.ptr.buffer, tr->data.ptr.offsets,
                             tr->data_size, tr->offsets_size);
        else
                binder_debug(BINDER_DEBUG_TRANSACTION,
                             "%d:%d BC_TRANSACTION %d -> %d - node %d, data %p-%p size %zd-%zd\n",
                             proc->pid, thread->pid, t->debug_id,
                             target_proc->pid, target_node->debug_id,
                             tr->data.ptr.buffer, tr->data.ptr.offsets,
                             tr->data_size, tr->offsets_size);

        if (!reply && !(tr->flags & TF_ONE_WAY))
                t->from = thread;
        else
                t->from = NULL;
        t->sender_euid = proc->tsk->cred->euid;
        t->to_proc = target_proc;
        t->to_thread = target_thread;
        t->code = tr->code;
        t->flags = tr->flags;
        t->priority = task_nice(current);

        trace_binder_transaction(reply, t, target_node);

        t->buffer = binder_alloc_buf(target_proc, tr->data_size,
                tr->offsets_size, !reply && (t->flags & TF_ONE_WAY));
        if (t->buffer == NULL) {
                return_error = BR_FAILED_REPLY;
                goto err_binder_alloc_buf_failed;
        }
        t->buffer->allow_user_free = 0;
        t->buffer->debug_id = t->debug_id;
        t->buffer->transaction = t;
        t->buffer->target_node = target_node;
        trace_binder_transaction_alloc_buf(t->buffer);
        if (target_node)
                binder_inc_node(target_node, 1, 0, NULL);

        offp = (size_t *)(t->buffer->data + ALIGN(tr->data_size, sizeof(void *)));

        if (copy_from_user(t->buffer->data, tr->data.ptr.buffer, tr->data_size)) {
                binder_user_error("%d:%d got transaction with invalid data ptr\n",
                                proc->pid, thread->pid);
                return_error = BR_FAILED_REPLY;
                goto err_copy_data_failed;
        }
        if (copy_from_user(offp, tr->data.ptr.offsets, tr->offsets_size)) {
                binder_user_error("%d:%d got transaction with invalid offsets ptr\n",
                                proc->pid, thread->pid);
                return_error = BR_FAILED_REPLY;
                goto err_copy_data_failed;
        }
        if (!IS_ALIGNED(tr->offsets_size, sizeof(size_t))) {
                binder_user_error("%d:%d got transaction with invalid offsets size, %zd\n",
                                proc->pid, thread->pid, tr->offsets_size);
                return_error = BR_FAILED_REPLY;
                goto err_bad_offset;
        }
        off_end = (void *)offp + tr->offsets_size;
        for (; offp < off_end; offp++) {
                struct flat_binder_object *fp;
                if (*offp > t->buffer->data_size - sizeof(*fp) ||
                    t->buffer->data_size < sizeof(*fp) ||
                    !IS_ALIGNED(*offp, sizeof(void *))) {
                        binder_user_error("%d:%d got transaction with invalid offset, %zd\n",
                                        proc->pid, thread->pid, *offp);
                        return_error = BR_FAILED_REPLY;
                        goto err_bad_offset;
                }
                fp = (struct flat_binder_object *)(t->buffer->data + *offp);
                switch (fp->type) {
                case BINDER_TYPE_BINDER:
                case BINDER_TYPE_WEAK_BINDER: {
                        struct binder_ref *ref;
                        struct binder_node *node = binder_get_node(proc, fp->binder);
                        if (node == NULL) {
                                node = binder_new_node(proc, fp->binder, fp->cookie);
                                if (node == NULL) {
                                        return_error = BR_FAILED_REPLY;
                                        goto err_binder_new_node_failed;
                                }
                                node->min_priority = fp->flags & FLAT_BINDER_FLAG_PRIORITY_MASK;
                                node->accept_fds = !!(fp->flags & FLAT_BINDER_FLAG_ACCEPTS_FDS);
                        }
                        if (fp->cookie != node->cookie) {
                                binder_user_error("%d:%d sending u%p node %d, cookie mismatch %p != %p\n",
                                        proc->pid, thread->pid,
                                        fp->binder, node->debug_id,
                                        fp->cookie, node->cookie);
                                goto err_binder_get_ref_for_node_failed;
                        }
                        ref = binder_get_ref_for_node(target_proc, node);
                        if (ref == NULL) {
                                return_error = BR_FAILED_REPLY;
                                goto err_binder_get_ref_for_node_failed;
                        }
                        if (fp->type == BINDER_TYPE_BINDER)
                                fp->type = BINDER_TYPE_HANDLE;
                        else
                                fp->type = BINDER_TYPE_WEAK_HANDLE;
                        fp->handle = ref->desc;
                        binder_inc_ref(ref, fp->type == BINDER_TYPE_HANDLE,
                                       &thread->todo);

                        trace_binder_transaction_node_to_ref(t, node, ref);
                        binder_debug(BINDER_DEBUG_TRANSACTION,
                                     "        node %d u%p -> ref %d desc %d\n",
                                     node->debug_id, node->ptr, ref->debug_id,
                                     ref->desc);
                } break;
                case BINDER_TYPE_HANDLE:
                case BINDER_TYPE_WEAK_HANDLE: {
                        struct binder_ref *ref = binder_get_ref(proc, fp->handle);
                        if (ref == NULL) {
                                binder_user_error("%d:%d got transaction with invalid handle, %ld\n",
                                                proc->pid,
                                                thread->pid, fp->handle);
                                return_error = BR_FAILED_REPLY;
                                goto err_binder_get_ref_failed;
                        }
                        if (ref->node->proc == target_proc) {
                                if (fp->type == BINDER_TYPE_HANDLE)
                                        fp->type = BINDER_TYPE_BINDER;
                                else
                                        fp->type = BINDER_TYPE_WEAK_BINDER;
                                fp->binder = ref->node->ptr;
                                fp->cookie = ref->node->cookie;
                                binder_inc_node(ref->node, fp->type == BINDER_TYPE_BINDER, 0, NULL);
                                trace_binder_transaction_ref_to_node(t, ref);
                                binder_debug(BINDER_DEBUG_TRANSACTION,
                                             "        ref %d desc %d -> node %d u%p\n",
                                             ref->debug_id, ref->desc, ref->node->debug_id,
                                             ref->node->ptr);
                        } else {
                                struct binder_ref *new_ref;
                                new_ref = binder_get_ref_for_node(target_proc, ref->node);
                                if (new_ref == NULL) {
                                        return_error = BR_FAILED_REPLY;
                                        goto err_binder_get_ref_for_node_failed;
                                }
                                fp->handle = new_ref->desc;
                                binder_inc_ref(new_ref, fp->type == BINDER_TYPE_HANDLE, NULL);
                                trace_binder_transaction_ref_to_ref(t, ref,
                                                                    new_ref);
                                binder_debug(BINDER_DEBUG_TRANSACTION,
                                             "        ref %d desc %d -> ref %d desc %d (node %d)\n",
                                             ref->debug_id, ref->desc, new_ref->debug_id,
                                             new_ref->desc, ref->node->debug_id);
                        }
                } break;

                case BINDER_TYPE_FD: {
                        int target_fd;
                        struct file *file;

                        if (reply) {
                                if (!(in_reply_to->flags & TF_ACCEPT_FDS)) {
                                        binder_user_error("%d:%d got reply with fd, %ld, but target does not allow fds\n",
                                                proc->pid, thread->pid, fp->handle);
                                        return_error = BR_FAILED_REPLY;
                                        goto err_fd_not_allowed;
                                }
                        } else if (!target_node->accept_fds) {
                                binder_user_error("%d:%d got transaction with fd, %ld, but target does not allow fds\n",
                                        proc->pid, thread->pid, fp->handle);
                                return_error = BR_FAILED_REPLY;
                                goto err_fd_not_allowed;
                        }

                        file = fget(fp->handle);
                        if (file == NULL) {
                                binder_user_error("%d:%d got transaction with invalid fd, %ld\n",
                                        proc->pid, thread->pid, fp->handle);
                                return_error = BR_FAILED_REPLY;
                                goto err_fget_failed;
                        }
                        target_fd = task_get_unused_fd_flags(target_proc, O_CLOEXEC);
                        if (target_fd < 0) {
                                fput(file);
                                return_error = BR_FAILED_REPLY;
                                goto err_get_unused_fd_failed;
                        }
                        task_fd_install(target_proc, target_fd, file);
                        trace_binder_transaction_fd(t, fp->handle, target_fd);
                        binder_debug(BINDER_DEBUG_TRANSACTION,
                                     "        fd %ld -> %d\n", fp->handle, target_fd);
                        /* TODO: fput? */
                        fp->handle = target_fd;
                } break;

                default:
                        binder_user_error("%d:%d got transaction with invalid object type, %lx\n",
                                proc->pid, thread->pid, fp->type);
                        return_error = BR_FAILED_REPLY;
                        goto err_bad_object_type;
                }
        }
        if (reply) {
                BUG_ON(t->buffer->async_transaction != 0);
                binder_pop_transaction(target_thread, in_reply_to);
        } else if (!(t->flags & TF_ONE_WAY)) {
                BUG_ON(t->buffer->async_transaction != 0);
                t->need_reply = 1;
                t->from_parent = thread->transaction_stack;
                thread->transaction_stack = t;
        } else {
                BUG_ON(target_node == NULL);
                BUG_ON(t->buffer->async_transaction != 1);
                if (target_node->has_async_transaction) {
                        target_list = &target_node->async_todo;
                        target_wait = NULL;
                } else
                        target_node->has_async_transaction = 1;
        }
        t->work.type = BINDER_WORK_TRANSACTION;
        list_add_tail(&t->work.entry, target_list);
        tcomplete->type = BINDER_WORK_TRANSACTION_COMPLETE;
        list_add_tail(&tcomplete->entry, &thread->todo);
        if (target_wait)
                wake_up_interruptible(target_wait);
        return;

err_get_unused_fd_failed:
err_fget_failed:
err_fd_not_allowed:
err_binder_get_ref_for_node_failed:
err_binder_get_ref_failed:
err_binder_new_node_failed:
err_bad_object_type:
err_bad_offset:
err_copy_data_failed:
        trace_binder_transaction_failed_buffer_release(t->buffer);
        binder_transaction_buffer_release(target_proc, t->buffer, offp);
        t->buffer->transaction = NULL;
        binder_free_buf(target_proc, t->buffer);
err_binder_alloc_buf_failed:
        kfree(tcomplete);
        binder_stats_deleted(BINDER_STAT_TRANSACTION_COMPLETE);
err_alloc_tcomplete_failed:
        kfree(t);
        binder_stats_deleted(BINDER_STAT_TRANSACTION);
err_alloc_t_failed:
err_bad_call_stack:
err_empty_call_stack:
err_dead_binder:
err_invalid_target_handle:
err_no_context_mgr_node:
        binder_debug(BINDER_DEBUG_FAILED_TRANSACTION,
                     "%d:%d transaction failed %d, size %zd-%zd\n",
                     proc->pid, thread->pid, return_error,
                     tr->data_size, tr->offsets_size);

        {
                struct binder_transaction_log_entry *fe;
                fe = binder_transaction_log_add(&binder_transaction_log_failed);
                *fe = *e;
        }

        BUG_ON(thread->return_error != BR_OK);
        if (in_reply_to) {
                thread->return_error = BR_TRANSACTION_COMPLETE;
                binder_send_failed_reply(in_reply_to, return_error);
        } else
                thread->return_error = return_error;
}

int binder_thread_write(struct binder_proc *proc, struct binder_thread *thread,
                        void __user *buffer, int size, signed long *consumed)
{
        uint32_t cmd;
        void __user *ptr = buffer + *consumed;
        void __user *end = buffer + size;

        while (ptr < end && thread->return_error == BR_OK) {
                if (get_user(cmd, (uint32_t __user *)ptr))
                        return -EFAULT;
                ptr += sizeof(uint32_t);
                trace_binder_command(cmd);
                if (_IOC_NR(cmd) < ARRAY_SIZE(binder_stats.bc)) {
                        binder_stats.bc[_IOC_NR(cmd)]++;
                        proc->stats.bc[_IOC_NR(cmd)]++;
                        thread->stats.bc[_IOC_NR(cmd)]++;
                }
                switch (cmd) {
                case BC_INCREFS:
                case BC_ACQUIRE:
                case BC_RELEASE:
                case BC_DECREFS: {
                        uint32_t target;
                        struct binder_ref *ref;
                        const char *debug_string;

                        if (get_user(target, (uint32_t __user *)ptr))
                                return -EFAULT;
                        ptr += sizeof(uint32_t);
                        if (target == 0 && binder_context_mgr_node &&
                            (cmd == BC_INCREFS || cmd == BC_ACQUIRE)) {
                                ref = binder_get_ref_for_node(proc,
                                               binder_context_mgr_node);
                                if (ref->desc != target) {
                                        binder_user_error("%d:%d tried to acquire reference to desc 0, got %d instead\n",
                                                proc->pid, thread->pid,
                                                ref->desc);
                                }
                        } else
                                ref = binder_get_ref(proc, target);
                        if (ref == NULL) {
                                binder_user_error("%d:%d refcount change on invalid ref %d\n",
                                        proc->pid, thread->pid, target);
                                break;
                        }
                        switch (cmd) {
                        case BC_INCREFS:
                                debug_string = "IncRefs";
                                binder_inc_ref(ref, 0, NULL);
                                break;
                        case BC_ACQUIRE:
                                debug_string = "Acquire";
                                binder_inc_ref(ref, 1, NULL);
                                break;
                        case BC_RELEASE:
                                debug_string = "Release";
                                binder_dec_ref(ref, 1);
                                break;
                        case BC_DECREFS:
                        default:
                                debug_string = "DecRefs";
                                binder_dec_ref(ref, 0);
                                break;
                        }
                        binder_debug(BINDER_DEBUG_USER_REFS,
                                     "%d:%d %s ref %d desc %d s %d w %d for node %d\n",
                                     proc->pid, thread->pid, debug_string, ref->debug_id,
                                     ref->desc, ref->strong, ref->weak, ref->node->debug_id);
                        break;
                }
                case BC_INCREFS_DONE:
                case BC_ACQUIRE_DONE: {
                        void __user *node_ptr;
                        void *cookie;
                        struct binder_node *node;

                        if (get_user(node_ptr, (void * __user *)ptr))
                                return -EFAULT;
                        ptr += sizeof(void *);
                        if (get_user(cookie, (void * __user *)ptr))
                                return -EFAULT;
                        ptr += sizeof(void *);
                        node = binder_get_node(proc, node_ptr);
                        if (node == NULL) {
                                binder_user_error("%d:%d %s u%p no match\n",
                                        proc->pid, thread->pid,
                                        cmd == BC_INCREFS_DONE ?
                                        "BC_INCREFS_DONE" :
                                        "BC_ACQUIRE_DONE",
                                        node_ptr);
                                break;
                        }
                        if (cookie != node->cookie) {
                                binder_user_error("%d:%d %s u%p node %d cookie mismatch %p != %p\n",
                                        proc->pid, thread->pid,
                                        cmd == BC_INCREFS_DONE ?
                                        "BC_INCREFS_DONE" : "BC_ACQUIRE_DONE",
                                        node_ptr, node->debug_id,
                                        cookie, node->cookie);
                                break;
                        }
                        if (cmd == BC_ACQUIRE_DONE) {
                                if (node->pending_strong_ref == 0) {
                                        binder_user_error("%d:%d BC_ACQUIRE_DONE node %d has no pending acquire request\n",
                                                proc->pid, thread->pid,
                                                node->debug_id);
                                        break;
                                }
                                node->pending_strong_ref = 0;
                        } else {
                                if (node->pending_weak_ref == 0) {
                                        binder_user_error("%d:%d BC_INCREFS_DONE node %d has no pending increfs request\n",
                                                proc->pid, thread->pid,
                                                node->debug_id);
                                        break;
                                }
                                node->pending_weak_ref = 0;
                        }
                        binder_dec_node(node, cmd == BC_ACQUIRE_DONE, 0);
                        binder_debug(BINDER_DEBUG_USER_REFS,
                                     "%d:%d %s node %d ls %d lw %d\n",
                                     proc->pid, thread->pid,
                                     cmd == BC_INCREFS_DONE ? "BC_INCREFS_DONE" : "BC_ACQUIRE_DONE",
                                     node->debug_id, node->local_strong_refs, node->local_weak_refs);
                        break;
                }
                case BC_ATTEMPT_ACQUIRE:
                        pr_err("BC_ATTEMPT_ACQUIRE not supported\n");
                        return -EINVAL;
                case BC_ACQUIRE_RESULT:
                        pr_err("BC_ACQUIRE_RESULT not supported\n");
                        return -EINVAL;

                case BC_FREE_BUFFER: {
                        void __user *data_ptr;
                        struct binder_buffer *buffer;

                        if (get_user(data_ptr, (void * __user *)ptr))
                                return -EFAULT;
                        ptr += sizeof(void *);

                        buffer = binder_buffer_lookup(proc, data_ptr);
                        if (buffer == NULL) {
                                binder_user_error("%d:%d BC_FREE_BUFFER u%p no match\n",
                                        proc->pid, thread->pid, data_ptr);
                                break;
                        }
                        if (!buffer->allow_user_free) {
                                binder_user_error("%d:%d BC_FREE_BUFFER u%p matched unreturned buffer\n",
                                        proc->pid, thread->pid, data_ptr);
                                break;
                        }
                        binder_debug(BINDER_DEBUG_FREE_BUFFER,
                                     "%d:%d BC_FREE_BUFFER u%p found buffer %d for %s transaction\n",
                                     proc->pid, thread->pid, data_ptr, buffer->debug_id,
                                     buffer->transaction ? "active" : "finished");

                        if (buffer->transaction) {
                                buffer->transaction->buffer = NULL;
                                buffer->transaction = NULL;
                        }
                        if (buffer->async_transaction && buffer->target_node) {
                                BUG_ON(!buffer->target_node->has_async_transaction);
                                if (list_empty(&buffer->target_node->async_todo))
                                        buffer->target_node->has_async_transaction = 0;
                                else
                                        list_move_tail(buffer->target_node->async_todo.next, &thread->todo);
                        }
                        trace_binder_transaction_buffer_release(buffer);
                        binder_transaction_buffer_release(proc, buffer, NULL);
                        binder_free_buf(proc, buffer);
                        break;
                }

                case BC_TRANSACTION:
                case BC_REPLY: {
                        struct binder_transaction_data tr;

                        if (copy_from_user(&tr, ptr, sizeof(tr)))
                                return -EFAULT;
                        ptr += sizeof(tr);
                        binder_transaction(proc, thread, &tr, cmd == BC_REPLY);
                        break;
                }

                case BC_REGISTER_LOOPER:
                        binder_debug(BINDER_DEBUG_THREADS,
                                     "%d:%d BC_REGISTER_LOOPER\n",
                                     proc->pid, thread->pid);
                        if (thread->looper & BINDER_LOOPER_STATE_ENTERED) {
                                thread->looper |= BINDER_LOOPER_STATE_INVALID;
                                binder_user_error("%d:%d ERROR: BC_REGISTER_LOOPER called after BC_ENTER_LOOPER\n",
                                        proc->pid, thread->pid);
                        } else if (proc->requested_threads == 0) {
                                thread->looper |= BINDER_LOOPER_STATE_INVALID;
                                binder_user_error("%d:%d ERROR: BC_REGISTER_LOOPER called without request\n",
                                        proc->pid, thread->pid);
                        } else {
                                proc->requested_threads--;
                                proc->requested_threads_started++;
                        }
                        thread->looper |= BINDER_LOOPER_STATE_REGISTERED;
                        break;
                case BC_ENTER_LOOPER:
                        binder_debug(BINDER_DEBUG_THREADS,
                                     "%d:%d BC_ENTER_LOOPER\n",
                                     proc->pid, thread->pid);
                        if (thread->looper & BINDER_LOOPER_STATE_REGISTERED) {
                                thread->looper |= BINDER_LOOPER_STATE_INVALID;
                                binder_user_error("%d:%d ERROR: BC_ENTER_LOOPER called after BC_REGISTER_LOOPER\n",
                                        proc->pid, thread->pid);
                        }
                        thread->looper |= BINDER_LOOPER_STATE_ENTERED;
                        break;
                case BC_EXIT_LOOPER:
                        binder_debug(BINDER_DEBUG_THREADS,
                                     "%d:%d BC_EXIT_LOOPER\n",
                                     proc->pid, thread->pid);
                        thread->looper |= BINDER_LOOPER_STATE_EXITED;
                        break;

                case BC_REQUEST_DEATH_NOTIFICATION:
                case BC_CLEAR_DEATH_NOTIFICATION: {
                        uint32_t target;
                        void __user *cookie;
                        struct binder_ref *ref;
                        struct binder_ref_death *death;

                        if (get_user(target, (uint32_t __user *)ptr))
                                return -EFAULT;
                        ptr += sizeof(uint32_t);
                        if (get_user(cookie, (void __user * __user *)ptr))
                                return -EFAULT;
                        ptr += sizeof(void *);
                        ref = binder_get_ref(proc, target);
                        if (ref == NULL) {
                                binder_user_error("%d:%d %s invalid ref %d\n",
                                        proc->pid, thread->pid,
                                        cmd == BC_REQUEST_DEATH_NOTIFICATION ?
                                        "BC_REQUEST_DEATH_NOTIFICATION" :
                                        "BC_CLEAR_DEATH_NOTIFICATION",
                                        target);
                                break;
                        }

                        binder_debug(BINDER_DEBUG_DEATH_NOTIFICATION,
                                     "%d:%d %s %p ref %d desc %d s %d w %d for node %d\n",
                                     proc->pid, thread->pid,
                                     cmd == BC_REQUEST_DEATH_NOTIFICATION ?
                                     "BC_REQUEST_DEATH_NOTIFICATION" :
                                     "BC_CLEAR_DEATH_NOTIFICATION",
                                     cookie, ref->debug_id, ref->desc,
                                     ref->strong, ref->weak, ref->node->debug_id);

                        if (cmd == BC_REQUEST_DEATH_NOTIFICATION) {
                                if (ref->death) {
                                        binder_user_error("%d:%d BC_REQUEST_DEATH_NOTIFICATION death notification already set\n",
                                                proc->pid, thread->pid);
                                        break;
                                }
                                death = kzalloc(sizeof(*death), GFP_KERNEL);
                                if (death == NULL) {
                                        thread->return_error = BR_ERROR;
                                        binder_debug(BINDER_DEBUG_FAILED_TRANSACTION,
                                                     "%d:%d BC_REQUEST_DEATH_NOTIFICATION failed\n",
                                                     proc->pid, thread->pid);
                                        break;
                                }
                                binder_stats_created(BINDER_STAT_DEATH);
                                INIT_LIST_HEAD(&death->work.entry);
                                death->cookie = cookie;
                                ref->death = death;
                                if (ref->node->proc == NULL) {
                                        ref->death->work.type = BINDER_WORK_DEAD_BINDER;
                                        if (thread->looper & (BINDER_LOOPER_STATE_REGISTERED | BINDER_LOOPER_STATE_ENTERED)) {
                                                list_add_tail(&ref->death->work.entry, &thread->todo);
                                        } else {
                                                list_add_tail(&ref->death->work.entry, &proc->todo);
                                                wake_up_interruptible(&proc->wait);
                                        }
                                }
                        } else {
                                if (ref->death == NULL) {
                                        binder_user_error("%d:%d BC_CLEAR_DEATH_NOTIFICATION death notification not active\n",
                                                proc->pid, thread->pid);
                                        break;
                                }
                                death = ref->death;
                                if (death->cookie != cookie) {
                                        binder_user_error("%d:%d BC_CLEAR_DEATH_NOTIFICATION death notification cookie mismatch %p != %p\n",
                                                proc->pid, thread->pid,
                                                death->cookie, cookie);
                                        break;
                                }
                                ref->death = NULL;
                                if (list_empty(&death->work.entry)) {
                                        death->work.type = BINDER_WORK_CLEAR_DEATH_NOTIFICATION;
                                        if (thread->looper & (BINDER_LOOPER_STATE_REGISTERED | BINDER_LOOPER_STATE_ENTERED)) {

                                                list_add_tail(&death->work.entry, &thread->todo);
                                        } else {
                                                list_add_tail(&death->work.entry, &proc->todo);
                                                wake_up_interruptible(&proc->wait);
                                        }
                                } else {
                                        BUG_ON(death->work.type != BINDER_WORK_DEAD_BINDER);
                                        death->work.type = BINDER_WORK_DEAD_BINDER_AND_CLEAR;
                                }
                        }
                } break;
                case BC_DEAD_BINDER_DONE: {
                        struct binder_work *w;
                        void __user *cookie;
                        struct binder_ref_death *death = NULL;
                        if (get_user(cookie, (void __user * __user *)ptr))
                                return -EFAULT;

                        ptr += sizeof(void *);
                        list_for_each_entry(w, &proc->delivered_death, entry) {
                                struct binder_ref_death *tmp_death = container_of(w, struct binder_ref_death, work);
                                if (tmp_death->cookie == cookie) {
                                        death = tmp_death;
                                        break;
                                }
                        }
                        binder_debug(BINDER_DEBUG_DEAD_BINDER,
                                     "%d:%d BC_DEAD_BINDER_DONE %p found %p\n",
                                     proc->pid, thread->pid, cookie, death);
                        if (death == NULL) {
                                binder_user_error("%d:%d BC_DEAD_BINDER_DONE %p not found\n",
                                        proc->pid, thread->pid, cookie);
                                break;
                        }

                        list_del_init(&death->work.entry);
                        if (death->work.type == BINDER_WORK_DEAD_BINDER_AND_CLEAR) {
                                death->work.type = BINDER_WORK_CLEAR_DEATH_NOTIFICATION;
                                if (thread->looper & (BINDER_LOOPER_STATE_REGISTERED | BINDER_LOOPER_STATE_ENTERED)) {
                                        list_add_tail(&death->work.entry, &thread->todo);
                                } else {
                                        list_add_tail(&death->work.entry, &proc->todo);
                                        wake_up_interruptible(&proc->wait);
                                }
                        }
                } break;

                default:
                        pr_err("%d:%d unknown command %d\n",
                               proc->pid, thread->pid, cmd);
                        return -EINVAL;
                }
                *consumed = ptr - buffer;
        }
        return 0;
}

void binder_stat_br(struct binder_proc *proc, struct binder_thread *thread,
                    uint32_t cmd)
{
        trace_binder_return(cmd);
        if (_IOC_NR(cmd) < ARRAY_SIZE(binder_stats.br)) {
                binder_stats.br[_IOC_NR(cmd)]++;
                proc->stats.br[_IOC_NR(cmd)]++;
                thread->stats.br[_IOC_NR(cmd)]++;
        }
}

static int binder_has_proc_work(struct binder_proc *proc,
                                struct binder_thread *thread)
{
        return !list_empty(&proc->todo) ||
                (thread->looper & BINDER_LOOPER_STATE_NEED_RETURN);
}

static int binder_has_thread_work(struct binder_thread *thread)
{
        return !list_empty(&thread->todo) || thread->return_error != BR_OK ||
                (thread->looper & BINDER_LOOPER_STATE_NEED_RETURN);
}

static int binder_thread_read(struct binder_proc *proc,
                              struct binder_thread *thread,
                              void  __user *buffer, int size,
                              signed long *consumed, int non_block)
{
        void __user *ptr = buffer + *consumed;
        void __user *end = buffer + size;

        int ret = 0;
        int wait_for_proc_work;

        if (*consumed == 0) {
                if (put_user(BR_NOOP, (uint32_t __user *)ptr))
                        return -EFAULT;
                ptr += sizeof(uint32_t);
        }

retry:
        wait_for_proc_work = thread->transaction_stack == NULL &&
                                list_empty(&thread->todo);

        if (thread->return_error != BR_OK && ptr < end) {
                if (thread->return_error2 != BR_OK) {
                        if (put_user(thread->return_error2, (uint32_t __user *)ptr))
                                return -EFAULT;
                        ptr += sizeof(uint32_t);
                        binder_stat_br(proc, thread, thread->return_error2);
                        if (ptr == end)
                                goto done;
                        thread->return_error2 = BR_OK;
                }
                if (put_user(thread->return_error, (uint32_t __user *)ptr))
                        return -EFAULT;
                ptr += sizeof(uint32_t);
                binder_stat_br(proc, thread, thread->return_error);
                thread->return_error = BR_OK;
                goto done;
        }


        thread->looper |= BINDER_LOOPER_STATE_WAITING;
        if (wait_for_proc_work)
                proc->ready_threads++;

        binder_unlock(__func__);

        trace_binder_wait_for_work(wait_for_proc_work,
                                   !!thread->transaction_stack,
                                   !list_empty(&thread->todo));
        if (wait_for_proc_work) {
                if (!(thread->looper & (BINDER_LOOPER_STATE_REGISTERED |
                                        BINDER_LOOPER_STATE_ENTERED))) {
                        binder_user_error("%d:%d ERROR: Thread waiting for process work before calling BC_REGISTER_LOOPER or BC_ENTER_LOOPER (state %x)\n",
                                proc->pid, thread->pid, thread->looper);
                        wait_event_interruptible(binder_user_error_wait,
                                                 binder_stop_on_user_error < 2);
                }
                binder_set_nice(proc->default_priority);
                if (non_block) {
                        if (!binder_has_proc_work(proc, thread))
                                ret = -EAGAIN;
                } else
                        ret = wait_event_freezable_exclusive(proc->wait, binder_has_proc_work(proc, thread));
        } else {
                if (non_block) {
                        if (!binder_has_thread_work(thread))
                                ret = -EAGAIN;
                } else
                        ret = wait_event_freezable(thread->wait, binder_has_thread_work(thread));
        }

        binder_lock(__func__);

        if (wait_for_proc_work)
                proc->ready_threads--;
        thread->looper &= ~BINDER_LOOPER_STATE_WAITING;

        if (ret)
                return ret;

        while (1) {
                uint32_t cmd;
                struct binder_transaction_data tr;
                struct binder_work *w;
                struct binder_transaction *t = NULL;

                if (!list_empty(&thread->todo))
                        w = list_first_entry(&thread->todo, struct binder_work, entry);
                else if (!list_empty(&proc->todo) && wait_for_proc_work)
                        w = list_first_entry(&proc->todo, struct binder_work, entry);
                else {
                        if (ptr - buffer == 4 && !(thread->looper & BINDER_LOOPER_STATE_NEED_RETURN)) /* no data added */
                                goto retry;
                        break;
                }

                if (end - ptr < sizeof(tr) + 4)
                        break;

                switch (w->type) {
                case BINDER_WORK_TRANSACTION: {
                        t = container_of(w, struct binder_transaction, work);
                } break;
                case BINDER_WORK_TRANSACTION_COMPLETE: {
                        cmd = BR_TRANSACTION_COMPLETE;
                        if (put_user(cmd, (uint32_t __user *)ptr))
                                return -EFAULT;
                        ptr += sizeof(uint32_t);

                        binder_stat_br(proc, thread, cmd);
                        binder_debug(BINDER_DEBUG_TRANSACTION_COMPLETE,
                                     "%d:%d BR_TRANSACTION_COMPLETE\n",
                                     proc->pid, thread->pid);

                        list_del(&w->entry);
                        kfree(w);
                        binder_stats_deleted(BINDER_STAT_TRANSACTION_COMPLETE);
                } break;
                case BINDER_WORK_NODE: {
                        struct binder_node *node = container_of(w, struct binder_node, work);
                        uint32_t cmd = BR_NOOP;
                        const char *cmd_name;
                        int strong = node->internal_strong_refs || node->local_strong_refs;
                        int weak = !hlist_empty(&node->refs) || node->local_weak_refs || strong;
                        if (weak && !node->has_weak_ref) {
                                cmd = BR_INCREFS;
                                cmd_name = "BR_INCREFS";
                                node->has_weak_ref = 1;
                                node->pending_weak_ref = 1;
                                node->local_weak_refs++;
                        } else if (strong && !node->has_strong_ref) {
                                cmd = BR_ACQUIRE;
                                cmd_name = "BR_ACQUIRE";
                                node->has_strong_ref = 1;
                                node->pending_strong_ref = 1;
                                node->local_strong_refs++;
                        } else if (!strong && node->has_strong_ref) {
                                cmd = BR_RELEASE;
                                cmd_name = "BR_RELEASE";
                                node->has_strong_ref = 0;
                        } else if (!weak && node->has_weak_ref) {
                                cmd = BR_DECREFS;
                                cmd_name = "BR_DECREFS";
                                node->has_weak_ref = 0;
                        }
                        if (cmd != BR_NOOP) {
                                if (put_user(cmd, (uint32_t __user *)ptr))
                                        return -EFAULT;
                                ptr += sizeof(uint32_t);
                                if (put_user(node->ptr, (void * __user *)ptr))
                                        return -EFAULT;
                                ptr += sizeof(void *);
                                if (put_user(node->cookie, (void * __user *)ptr))
                                        return -EFAULT;
                                ptr += sizeof(void *);

                                binder_stat_br(proc, thread, cmd);
                                binder_debug(BINDER_DEBUG_USER_REFS,
                                             "%d:%d %s %d u%p c%p\n",
                                             proc->pid, thread->pid, cmd_name, node->debug_id, node->ptr, node->cookie);
                        } else {
                                list_del_init(&w->entry);
                                if (!weak && !strong) {
                                        binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                                                     "%d:%d node %d u%p c%p deleted\n",
                                                     proc->pid, thread->pid, node->debug_id,
                                                     node->ptr, node->cookie);
                                        rb_erase(&node->rb_node, &proc->nodes);
                                        kfree(node);
                                        binder_stats_deleted(BINDER_STAT_NODE);
                                } else {
                                        binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                                                     "%d:%d node %d u%p c%p state unchanged\n",
                                                     proc->pid, thread->pid, node->debug_id, node->ptr,
                                                     node->cookie);
                                }
                        }
                } break;
                case BINDER_WORK_DEAD_BINDER:
                case BINDER_WORK_DEAD_BINDER_AND_CLEAR:
                case BINDER_WORK_CLEAR_DEATH_NOTIFICATION: {
                        struct binder_ref_death *death;
                        uint32_t cmd;

                        death = container_of(w, struct binder_ref_death, work);
                        if (w->type == BINDER_WORK_CLEAR_DEATH_NOTIFICATION)
                                cmd = BR_CLEAR_DEATH_NOTIFICATION_DONE;
                        else
                                cmd = BR_DEAD_BINDER;
                        if (put_user(cmd, (uint32_t __user *)ptr))
                                return -EFAULT;
                        ptr += sizeof(uint32_t);
                        if (put_user(death->cookie, (void * __user *)ptr))
                                return -EFAULT;
                        ptr += sizeof(void *);
                        binder_stat_br(proc, thread, cmd);
                        binder_debug(BINDER_DEBUG_DEATH_NOTIFICATION,
                                     "%d:%d %s %p\n",
                                      proc->pid, thread->pid,
                                      cmd == BR_DEAD_BINDER ?
                                      "BR_DEAD_BINDER" :
                                      "BR_CLEAR_DEATH_NOTIFICATION_DONE",
                                      death->cookie);

                        if (w->type == BINDER_WORK_CLEAR_DEATH_NOTIFICATION) {
                                list_del(&w->entry);
                                kfree(death);
                                binder_stats_deleted(BINDER_STAT_DEATH);
                        } else
                                list_move(&w->entry, &proc->delivered_death);
                        if (cmd == BR_DEAD_BINDER)
                                goto done; /* DEAD_BINDER notifications can cause transactions */
                } break;
                }

                if (!t)
                        continue;

                BUG_ON(t->buffer == NULL);
                if (t->buffer->target_node) {
                        struct binder_node *target_node = t->buffer->target_node;
                        tr.target.ptr = target_node->ptr;
                        tr.cookie =  target_node->cookie;
                        t->saved_priority = task_nice(current);
                        if (t->priority < target_node->min_priority &&
                            !(t->flags & TF_ONE_WAY))
                                binder_set_nice(t->priority);
                        else if (!(t->flags & TF_ONE_WAY) ||
                                 t->saved_priority > target_node->min_priority)
                                binder_set_nice(target_node->min_priority);
                        cmd = BR_TRANSACTION;
                } else {
                        tr.target.ptr = NULL;
                        tr.cookie = NULL;
                        cmd = BR_REPLY;
                }
                tr.code = t->code;
                tr.flags = t->flags;
                tr.sender_euid = from_kuid(current_user_ns(), t->sender_euid);

                if (t->from) {
                        struct task_struct *sender = t->from->proc->tsk;
                        tr.sender_pid = task_tgid_nr_ns(sender,
                                                        task_active_pid_ns(current));
                } else {
                        tr.sender_pid = 0;
                }

                tr.data_size = t->buffer->data_size;
                tr.offsets_size = t->buffer->offsets_size;
                tr.data.ptr.buffer = (void *)t->buffer->data +
                                        proc->user_buffer_offset;
                tr.data.ptr.offsets = tr.data.ptr.buffer +
                                        ALIGN(t->buffer->data_size,
                                            sizeof(void *));

                if (put_user(cmd, (uint32_t __user *)ptr))
                        return -EFAULT;
                ptr += sizeof(uint32_t);
                if (copy_to_user(ptr, &tr, sizeof(tr)))
                        return -EFAULT;
                ptr += sizeof(tr);

                trace_binder_transaction_received(t);
                binder_stat_br(proc, thread, cmd);
                binder_debug(BINDER_DEBUG_TRANSACTION,
                             "%d:%d %s %d %d:%d, cmd %d size %zd-%zd ptr %p-%p\n",
                             proc->pid, thread->pid,
                             (cmd == BR_TRANSACTION) ? "BR_TRANSACTION" :
                             "BR_REPLY",
                             t->debug_id, t->from ? t->from->proc->pid : 0,
                             t->from ? t->from->pid : 0, cmd,
                             t->buffer->data_size, t->buffer->offsets_size,
                             tr.data.ptr.buffer, tr.data.ptr.offsets);

                list_del(&t->work.entry);
                t->buffer->allow_user_free = 1;
                if (cmd == BR_TRANSACTION && !(t->flags & TF_ONE_WAY)) {
                        t->to_parent = thread->transaction_stack;
                        t->to_thread = thread;
                        thread->transaction_stack = t;
                } else {
                        t->buffer->transaction = NULL;
                        kfree(t);
                        binder_stats_deleted(BINDER_STAT_TRANSACTION);
                }
                break;
        }

done:

        *consumed = ptr - buffer;
        if (proc->requested_threads + proc->ready_threads == 0 &&
            proc->requested_threads_started < proc->max_threads &&
            (thread->looper & (BINDER_LOOPER_STATE_REGISTERED |
             BINDER_LOOPER_STATE_ENTERED)) /* the user-space code fails to */
             /*spawn a new thread if we leave this out */) {
                proc->requested_threads++;
                binder_debug(BINDER_DEBUG_THREADS,
                             "%d:%d BR_SPAWN_LOOPER\n",
                             proc->pid, thread->pid);
                if (put_user(BR_SPAWN_LOOPER, (uint32_t __user *)buffer))
                        return -EFAULT;
                binder_stat_br(proc, thread, BR_SPAWN_LOOPER);
        }
        return 0;
}

static void binder_release_work(struct list_head *list)
{
        struct binder_work *w;
        while (!list_empty(list)) {
                w = list_first_entry(list, struct binder_work, entry);
                list_del_init(&w->entry);
                switch (w->type) {
                case BINDER_WORK_TRANSACTION: {
                        struct binder_transaction *t;

                        t = container_of(w, struct binder_transaction, work);
                        if (t->buffer->target_node &&
                            !(t->flags & TF_ONE_WAY)) {
                                binder_send_failed_reply(t, BR_DEAD_REPLY);
                        } else {
                                binder_debug(BINDER_DEBUG_DEAD_TRANSACTION,
                                        "undelivered transaction %d\n",
                                        t->debug_id);
                                t->buffer->transaction = NULL;
                                kfree(t);
                                binder_stats_deleted(BINDER_STAT_TRANSACTION);
                        }
                } break;
                case BINDER_WORK_TRANSACTION_COMPLETE: {
                        binder_debug(BINDER_DEBUG_DEAD_TRANSACTION,
                                "undelivered TRANSACTION_COMPLETE\n");
                        kfree(w);
                        binder_stats_deleted(BINDER_STAT_TRANSACTION_COMPLETE);
                } break;
                case BINDER_WORK_DEAD_BINDER_AND_CLEAR:
                case BINDER_WORK_CLEAR_DEATH_NOTIFICATION: {
                        struct binder_ref_death *death;

                        death = container_of(w, struct binder_ref_death, work);
                        binder_debug(BINDER_DEBUG_DEAD_TRANSACTION,
                                "undelivered death notification, %p\n",
                                death->cookie);
                        kfree(death);
                        binder_stats_deleted(BINDER_STAT_DEATH);
                } break;
                default:
                        pr_err("unexpected work type, %d, not freed\n",
                               w->type);
                        break;
                }
        }

}

static struct binder_thread *binder_get_thread(struct binder_proc *proc)
{
        struct binder_thread *thread = NULL;
        struct rb_node *parent = NULL;
        struct rb_node **p = &proc->threads.rb_node;

        while (*p) {
                parent = *p;
                thread = rb_entry(parent, struct binder_thread, rb_node);

                if (current->pid < thread->pid)
                        p = &(*p)->rb_left;
                else if (current->pid > thread->pid)
                        p = &(*p)->rb_right;
                else
                        break;
        }
        if (*p == NULL) {
                thread = kzalloc(sizeof(*thread), GFP_KERNEL);
                if (thread == NULL)
                        return NULL;
                binder_stats_created(BINDER_STAT_THREAD);
                thread->proc = proc;
                thread->pid = current->pid;
                init_waitqueue_head(&thread->wait);
                INIT_LIST_HEAD(&thread->todo);
                rb_link_node(&thread->rb_node, parent, p);
                rb_insert_color(&thread->rb_node, &proc->threads);
                thread->looper |= BINDER_LOOPER_STATE_NEED_RETURN;
                thread->return_error = BR_OK;
                thread->return_error2 = BR_OK;
        }
        return thread;
}

static int binder_free_thread(struct binder_proc *proc,
                              struct binder_thread *thread)
{
        struct binder_transaction *t;
        struct binder_transaction *send_reply = NULL;
        int active_transactions = 0;

        rb_erase(&thread->rb_node, &proc->threads);
        t = thread->transaction_stack;
        if (t && t->to_thread == thread)
                send_reply = t;
        while (t) {
                active_transactions++;
                binder_debug(BINDER_DEBUG_DEAD_TRANSACTION,
                             "release %d:%d transaction %d %s, still active\n",
                              proc->pid, thread->pid,
                             t->debug_id,
                             (t->to_thread == thread) ? "in" : "out");

                if (t->to_thread == thread) {
                        t->to_proc = NULL;
                        t->to_thread = NULL;
                        if (t->buffer) {
                                t->buffer->transaction = NULL;
                                t->buffer = NULL;
                        }
                        t = t->to_parent;
                } else if (t->from == thread) {
                        t->from = NULL;
                        t = t->from_parent;
                } else
                        BUG();
        }
        if (send_reply)
                binder_send_failed_reply(send_reply, BR_DEAD_REPLY);
        binder_release_work(&thread->todo);
        kfree(thread);
        binder_stats_deleted(BINDER_STAT_THREAD);
        return active_transactions;
}

static unsigned int binder_poll(struct file *filp,
                                struct poll_table_struct *wait)
{
        struct binder_proc *proc = filp->private_data;
        struct binder_thread *thread = NULL;
        int wait_for_proc_work;

        binder_lock(__func__);

        thread = binder_get_thread(proc);

        wait_for_proc_work = thread->transaction_stack == NULL &&
                list_empty(&thread->todo) && thread->return_error == BR_OK;

        binder_unlock(__func__);

        if (wait_for_proc_work) {
                if (binder_has_proc_work(proc, thread))
                        return POLLIN;
                poll_wait(filp, &proc->wait, wait);
                if (binder_has_proc_work(proc, thread))
                        return POLLIN;
        } else {
                if (binder_has_thread_work(thread))
                        return POLLIN;
                poll_wait(filp, &thread->wait, wait);
                if (binder_has_thread_work(thread))
                        return POLLIN;
        }
        return 0;
}

static long binder_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
        int ret;
        struct binder_proc *proc = filp->private_data;
        struct binder_thread *thread;
        unsigned int size = _IOC_SIZE(cmd);
        void __user *ubuf = (void __user *)arg;

        /*pr_info("binder_ioctl: %d:%d %x %lx\n", proc->pid, current->pid, cmd, arg);*/

        trace_binder_ioctl(cmd, arg);

        ret = wait_event_interruptible(binder_user_error_wait, binder_stop_on_user_error < 2);
        if (ret)
                goto err_unlocked;

        binder_lock(__func__);
        thread = binder_get_thread(proc);
        if (thread == NULL) {
                ret = -ENOMEM;
                goto err;
        }

        switch (cmd) {
        case BINDER_WRITE_READ: {
                struct binder_write_read bwr;
                if (size != sizeof(struct binder_write_read)) {
                        ret = -EINVAL;
                        goto err;
                }
                if (copy_from_user(&bwr, ubuf, sizeof(bwr))) {
                        ret = -EFAULT;
                        goto err;
                }
                binder_debug(BINDER_DEBUG_READ_WRITE,
                             "%d:%d write %ld at %08lx, read %ld at %08lx\n",
                             proc->pid, thread->pid, bwr.write_size,
                             bwr.write_buffer, bwr.read_size, bwr.read_buffer);

                if (bwr.write_size > 0) {
                        ret = binder_thread_write(proc, thread, (void __user *)bwr.write_buffer, bwr.write_size, &bwr.write_consumed);
                        trace_binder_write_done(ret);
                        if (ret < 0) {
                                bwr.read_consumed = 0;
                                if (copy_to_user(ubuf, &bwr, sizeof(bwr)))
                                        ret = -EFAULT;
                                goto err;
                        }
                }
                if (bwr.read_size > 0) {
                        ret = binder_thread_read(proc, thread, (void __user *)bwr.read_buffer, bwr.read_size, &bwr.read_consumed, filp->f_flags & O_NONBLOCK);
                        trace_binder_read_done(ret);
                        if (!list_empty(&proc->todo))
                                wake_up_interruptible(&proc->wait);
                        if (ret < 0) {
                                if (copy_to_user(ubuf, &bwr, sizeof(bwr)))
                                        ret = -EFAULT;
                                goto err;
                        }
                }
                binder_debug(BINDER_DEBUG_READ_WRITE,
                             "%d:%d wrote %ld of %ld, read return %ld of %ld\n",
                             proc->pid, thread->pid, bwr.write_consumed, bwr.write_size,
                             bwr.read_consumed, bwr.read_size);
                if (copy_to_user(ubuf, &bwr, sizeof(bwr))) {
                        ret = -EFAULT;
                        goto err;
                }
                break;
        }
        case BINDER_SET_MAX_THREADS:
                if (copy_from_user(&proc->max_threads, ubuf, sizeof(proc->max_threads))) {
                        ret = -EINVAL;
                        goto err;
                }
                break;
        case BINDER_SET_CONTEXT_MGR:
                if (binder_context_mgr_node != NULL) {
                        pr_err("BINDER_SET_CONTEXT_MGR already set\n");
                        ret = -EBUSY;
                        goto err;
                }
                if (uid_valid(binder_context_mgr_uid)) {
                        if (!uid_eq(binder_context_mgr_uid, current->cred->euid)) {
                                pr_err("BINDER_SET_CONTEXT_MGR bad uid %d != %d\n",
                                       from_kuid(&init_user_ns, current->cred->euid),
                                       from_kuid(&init_user_ns, binder_context_mgr_uid));
                                ret = -EPERM;
                                goto err;
                        }
                } else
                        binder_context_mgr_uid = current->cred->euid;
                binder_context_mgr_node = binder_new_node(proc, NULL, NULL);
                if (binder_context_mgr_node == NULL) {
                        ret = -ENOMEM;
                        goto err;
                }
                binder_context_mgr_node->local_weak_refs++;
                binder_context_mgr_node->local_strong_refs++;
                binder_context_mgr_node->has_strong_ref = 1;
                binder_context_mgr_node->has_weak_ref = 1;
                break;
        case BINDER_THREAD_EXIT:
                binder_debug(BINDER_DEBUG_THREADS, "%d:%d exit\n",
                             proc->pid, thread->pid);
                binder_free_thread(proc, thread);
                thread = NULL;
                break;
        case BINDER_VERSION:
                if (size != sizeof(struct binder_version)) {
                        ret = -EINVAL;
                        goto err;
                }
                if (put_user(BINDER_CURRENT_PROTOCOL_VERSION, &((struct binder_version *)ubuf)->protocol_version)) {
                        ret = -EINVAL;
                        goto err;
                }
                break;
        default:
                ret = -EINVAL;
                goto err;
        }
        ret = 0;
err:
        if (thread)
                thread->looper &= ~BINDER_LOOPER_STATE_NEED_RETURN;
        binder_unlock(__func__);
        wait_event_interruptible(binder_user_error_wait, binder_stop_on_user_error < 2);
        if (ret && ret != -ERESTARTSYS)
                pr_info("%d:%d ioctl %x %lx returned %d\n", proc->pid, current->pid, cmd, arg, ret);
err_unlocked:
        trace_binder_ioctl_done(ret);
        return ret;
}

static void binder_vma_open(struct vm_area_struct *vma)
{
        struct binder_proc *proc = vma->vm_private_data;
        binder_debug(BINDER_DEBUG_OPEN_CLOSE,
                     "%d open vm area %lx-%lx (%ld K) vma %lx pagep %lx\n",
                     proc->pid, vma->vm_start, vma->vm_end,
                     (vma->vm_end - vma->vm_start) / SZ_1K, vma->vm_flags,
                     (unsigned long)pgprot_val(vma->vm_page_prot));
}

static void binder_vma_close(struct vm_area_struct *vma)
{
        struct binder_proc *proc = vma->vm_private_data;
        binder_debug(BINDER_DEBUG_OPEN_CLOSE,
                     "%d close vm area %lx-%lx (%ld K) vma %lx pagep %lx\n",
                     proc->pid, vma->vm_start, vma->vm_end,
                     (vma->vm_end - vma->vm_start) / SZ_1K, vma->vm_flags,
                     (unsigned long)pgprot_val(vma->vm_page_prot));
        proc->vma = NULL;
        proc->vma_vm_mm = NULL;
        binder_defer_work(proc, BINDER_DEFERRED_PUT_FILES);
}

static struct vm_operations_struct binder_vm_ops = {
        .open = binder_vma_open,
        .close = binder_vma_close,
};

static int binder_mmap(struct file *filp, struct vm_area_struct *vma)
{
        int ret;
        struct vm_struct *area;
        struct binder_proc *proc = filp->private_data;
        const char *failure_string;
        struct binder_buffer *buffer;

        if (proc->tsk != current)
                return -EINVAL;

        if ((vma->vm_end - vma->vm_start) > SZ_4M)
                vma->vm_end = vma->vm_start + SZ_4M;

        binder_debug(BINDER_DEBUG_OPEN_CLOSE,
                     "binder_mmap: %d %lx-%lx (%ld K) vma %lx pagep %lx\n",
                     proc->pid, vma->vm_start, vma->vm_end,
                     (vma->vm_end - vma->vm_start) / SZ_1K, vma->vm_flags,
                     (unsigned long)pgprot_val(vma->vm_page_prot));

        if (vma->vm_flags & FORBIDDEN_MMAP_FLAGS) {
                ret = -EPERM;
                failure_string = "bad vm_flags";
                goto err_bad_arg;
        }
        vma->vm_flags = (vma->vm_flags | VM_DONTCOPY) & ~VM_MAYWRITE;

        mutex_lock(&binder_mmap_lock);
        if (proc->buffer) {
                ret = -EBUSY;
                failure_string = "already mapped";
                goto err_already_mapped;
        }

        area = get_vm_area(vma->vm_end - vma->vm_start, VM_IOREMAP);
        if (area == NULL) {
                ret = -ENOMEM;
                failure_string = "get_vm_area";
                goto err_get_vm_area_failed;
        }
        proc->buffer = area->addr;
        proc->user_buffer_offset = vma->vm_start - (uintptr_t)proc->buffer;
        mutex_unlock(&binder_mmap_lock);

#ifdef CONFIG_CPU_CACHE_VIPT
        if (cache_is_vipt_aliasing()) {
                while (CACHE_COLOUR((vma->vm_start ^ (uint32_t)proc->buffer))) {
                        pr_info("binder_mmap: %d %lx-%lx maps %p bad alignment\n", proc->pid, vma->vm_start, vma->vm_end, proc->buffer);
                        vma->vm_start += PAGE_SIZE;
                }
        }
#endif
        proc->pages = kzalloc(sizeof(proc->pages[0]) * ((vma->vm_end - vma->vm_start) / PAGE_SIZE), GFP_KERNEL);
        if (proc->pages == NULL) {
                ret = -ENOMEM;
                failure_string = "alloc page array";
                goto err_alloc_pages_failed;
        }
        proc->buffer_size = vma->vm_end - vma->vm_start;

        vma->vm_ops = &binder_vm_ops;
        vma->vm_private_data = proc;

        if (binder_update_page_range(proc, 1, proc->buffer, proc->buffer + PAGE_SIZE, vma)) {
                ret = -ENOMEM;
                failure_string = "alloc small buf";
                goto err_alloc_small_buf_failed;
        }
        buffer = proc->buffer;
        INIT_LIST_HEAD(&proc->buffers);
        list_add(&buffer->entry, &proc->buffers);
        buffer->free = 1;
        binder_insert_free_buffer(proc, buffer);
        proc->free_async_space = proc->buffer_size / 2;
        barrier();
        proc->files = get_files_struct(current);
        proc->vma = vma;
        proc->vma_vm_mm = vma->vm_mm;

        /*pr_info("binder_mmap: %d %lx-%lx maps %p\n",
                 proc->pid, vma->vm_start, vma->vm_end, proc->buffer);*/
        return 0;

err_alloc_small_buf_failed:
        kfree(proc->pages);
        proc->pages = NULL;
err_alloc_pages_failed:
        mutex_lock(&binder_mmap_lock);
        vfree(proc->buffer);
        proc->buffer = NULL;
err_get_vm_area_failed:
err_already_mapped:
        mutex_unlock(&binder_mmap_lock);
err_bad_arg:
        pr_err("binder_mmap: %d %lx-%lx %s failed %d\n",
               proc->pid, vma->vm_start, vma->vm_end, failure_string, ret);
        return ret;
}

static int binder_open(struct inode *nodp, struct file *filp)
{
        struct binder_proc *proc;

        binder_debug(BINDER_DEBUG_OPEN_CLOSE, "binder_open: %d:%d\n",
                     current->group_leader->pid, current->pid);

        proc = kzalloc(sizeof(*proc), GFP_KERNEL);
        if (proc == NULL)
                return -ENOMEM;
        get_task_struct(current);
        proc->tsk = current;
        INIT_LIST_HEAD(&proc->todo);
        init_waitqueue_head(&proc->wait);
        proc->default_priority = task_nice(current);

        binder_lock(__func__);

        binder_stats_created(BINDER_STAT_PROC);
        hlist_add_head(&proc->proc_node, &binder_procs);
        proc->pid = current->group_leader->pid;
        INIT_LIST_HEAD(&proc->delivered_death);
        filp->private_data = proc;

        binder_unlock(__func__);

        if (binder_debugfs_dir_entry_proc) {
                char strbuf[11];
                snprintf(strbuf, sizeof(strbuf), "%u", proc->pid);
                proc->debugfs_entry = debugfs_create_file(strbuf, S_IRUGO,
                        binder_debugfs_dir_entry_proc, proc, &binder_proc_fops);
        }

        return 0;
}

static int binder_flush(struct file *filp, fl_owner_t id)
{
        struct binder_proc *proc = filp->private_data;

        binder_defer_work(proc, BINDER_DEFERRED_FLUSH);

        return 0;
}

static void binder_deferred_flush(struct binder_proc *proc)
{
        struct rb_node *n;
        int wake_count = 0;
        for (n = rb_first(&proc->threads); n != NULL; n = rb_next(n)) {
                struct binder_thread *thread = rb_entry(n, struct binder_thread, rb_node);
                thread->looper |= BINDER_LOOPER_STATE_NEED_RETURN;
                if (thread->looper & BINDER_LOOPER_STATE_WAITING) {
                        wake_up_interruptible(&thread->wait);
                        wake_count++;
                }
        }
        wake_up_interruptible_all(&proc->wait);

        binder_debug(BINDER_DEBUG_OPEN_CLOSE,
                     "binder_flush: %d woke %d threads\n", proc->pid,
                     wake_count);
}

static int binder_release(struct inode *nodp, struct file *filp)
{
        struct binder_proc *proc = filp->private_data;
        debugfs_remove(proc->debugfs_entry);
        binder_defer_work(proc, BINDER_DEFERRED_RELEASE);

        return 0;
}

static int binder_node_release(struct binder_node *node, int refs)
{
        struct binder_ref *ref;
        int death = 0;

        list_del_init(&node->work.entry);
        binder_release_work(&node->async_todo);

        if (hlist_empty(&node->refs)) {
                kfree(node);
                binder_stats_deleted(BINDER_STAT_NODE);

                return refs;
        }

        node->proc = NULL;
        node->local_strong_refs = 0;
        node->local_weak_refs = 0;
        hlist_add_head(&node->dead_node, &binder_dead_nodes);

        hlist_for_each_entry(ref, &node->refs, node_entry) {
                refs++;

                if (!ref->death)
                        goto out;

                death++;

                if (list_empty(&ref->death->work.entry)) {
                        ref->death->work.type = BINDER_WORK_DEAD_BINDER;
                        list_add_tail(&ref->death->work.entry,
                                      &ref->proc->todo);
                        wake_up_interruptible(&ref->proc->wait);
                } else
                        BUG();
        }

out:
        binder_debug(BINDER_DEBUG_DEAD_BINDER,
                     "node %d now dead, refs %d, death %d\n",
                     node->debug_id, refs, death);

        return refs;
}

static void binder_deferred_release(struct binder_proc *proc)
{
        struct binder_transaction *t;
        struct rb_node *n;
        int threads, nodes, incoming_refs, outgoing_refs, buffers,
                active_transactions, page_count;

        BUG_ON(proc->vma);
        BUG_ON(proc->files);

        hlist_del(&proc->proc_node);

        if (binder_context_mgr_node && binder_context_mgr_node->proc == proc) {
                binder_debug(BINDER_DEBUG_DEAD_BINDER,
                             "%s: %d context_mgr_node gone\n",
                             __func__, proc->pid);
                binder_context_mgr_node = NULL;
        }

        threads = 0;
        active_transactions = 0;
        while ((n = rb_first(&proc->threads))) {
                struct binder_thread *thread;

                thread = rb_entry(n, struct binder_thread, rb_node);
                threads++;
                active_transactions += binder_free_thread(proc, thread);
        }

        nodes = 0;
        incoming_refs = 0;
        while ((n = rb_first(&proc->nodes))) {
                struct binder_node *node;

                node = rb_entry(n, struct binder_node, rb_node);
                nodes++;
                rb_erase(&node->rb_node, &proc->nodes);
                incoming_refs = binder_node_release(node, incoming_refs);
        }

        outgoing_refs = 0;
        while ((n = rb_first(&proc->refs_by_desc))) {
                struct binder_ref *ref;

                ref = rb_entry(n, struct binder_ref, rb_node_desc);
                outgoing_refs++;
                binder_delete_ref(ref);
        }

        binder_release_work(&proc->todo);
        binder_release_work(&proc->delivered_death);

        buffers = 0;
        while ((n = rb_first(&proc->allocated_buffers))) {
                struct binder_buffer *buffer;

                buffer = rb_entry(n, struct binder_buffer, rb_node);

                t = buffer->transaction;
                if (t) {
                        t->buffer = NULL;
                        buffer->transaction = NULL;
                        pr_err("release proc %d, transaction %d, not freed\n",
                               proc->pid, t->debug_id);
                        /*BUG();*/
                }

                binder_free_buf(proc, buffer);
                buffers++;
        }

        binder_stats_deleted(BINDER_STAT_PROC);

        page_count = 0;