/*
 * Intel MIC Platform Software Stack (MPSS)
 *
 * Copyright(c) 2015 Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2, as
 * published by the Free Software Foundation.
 *
 * 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.
 *
 * Intel SCIF driver.
 *
 */
#include <linux/dma_remapping.h>
#include <linux/pagemap.h>
#include <linux/sched/mm.h>
#include <linux/sched/signal.h>

#include "scif_main.h"
#include "scif_map.h"

/* Used to skip ulimit checks for registrations with SCIF_MAP_KERNEL flag */
#define SCIF_MAP_ULIMIT 0x40

bool scif_ulimit_check = 1;

/**
 * scif_rma_ep_init:
 * @ep: end point
 *
 * Initialize RMA per EP data structures.
 */
void scif_rma_ep_init(struct scif_endpt *ep)
{
        struct scif_endpt_rma_info *rma = &ep->rma_info;

        mutex_init(&rma->rma_lock);
        init_iova_domain(&rma->iovad, PAGE_SIZE, SCIF_IOVA_START_PFN,
                         SCIF_DMA_64BIT_PFN);
        spin_lock_init(&rma->tc_lock);
        mutex_init(&rma->mmn_lock);
        INIT_LIST_HEAD(&rma->reg_list);
        INIT_LIST_HEAD(&rma->remote_reg_list);
        atomic_set(&rma->tw_refcount, 0);
        atomic_set(&rma->tcw_refcount, 0);
        atomic_set(&rma->tcw_total_pages, 0);
        atomic_set(&rma->fence_refcount, 0);

        rma->async_list_del = 0;
        rma->dma_chan = NULL;
        INIT_LIST_HEAD(&rma->mmn_list);
        INIT_LIST_HEAD(&rma->vma_list);
        init_waitqueue_head(&rma->markwq);
}

/**
 * scif_rma_ep_can_uninit:
 * @ep: end point
 *
 * Returns 1 if an endpoint can be uninitialized and 0 otherwise.
 */
int scif_rma_ep_can_uninit(struct scif_endpt *ep)
{
        int ret = 0;

        mutex_lock(&ep->rma_info.rma_lock);
        /* Destroy RMA Info only if both lists are empty */
        if (list_empty(&ep->rma_info.reg_list) &&
            list_empty(&ep->rma_info.remote_reg_list) &&
            list_empty(&ep->rma_info.mmn_list) &&
            !atomic_read(&ep->rma_info.tw_refcount) &&
            !atomic_read(&ep->rma_info.tcw_refcount) &&
            !atomic_read(&ep->rma_info.fence_refcount))
                ret = 1;
        mutex_unlock(&ep->rma_info.rma_lock);
        return ret;
}

/**
 * scif_create_pinned_pages:
 * @nr_pages: number of pages in window
 * @prot: read/write protection
 *
 * Allocate and prepare a set of pinned pages.
 */
static struct scif_pinned_pages *
scif_create_pinned_pages(int nr_pages, int prot)
{
        struct scif_pinned_pages *pin;

        might_sleep();
        pin = scif_zalloc(sizeof(*pin));
        if (!pin)
                goto error;

        pin->pages = scif_zalloc(nr_pages * sizeof(*pin->pages));
        if (!pin->pages)
                goto error_free_pinned_pages;

        pin->prot = prot;
        pin->magic = SCIFEP_MAGIC;
        return pin;

error_free_pinned_pages:
        scif_free(pin, sizeof(*pin));
error:
        return NULL;
}

/**
 * scif_destroy_pinned_pages:
 * @pin: A set of pinned pages.
 *
 * Deallocate resources for pinned pages.
 */
static int scif_destroy_pinned_pages(struct scif_pinned_pages *pin)
{
        int j;
        int writeable = pin->prot & SCIF_PROT_WRITE;
        int kernel = SCIF_MAP_KERNEL & pin->map_flags;

        for (j = 0; j < pin->nr_pages; j++) {
                if (pin->pages[j] && !kernel) {
                        if (writeable)
                                SetPageDirty(pin->pages[j]);
                        put_page(pin->pages[j]);
                }
        }

        scif_free(pin->pages,
                  pin->nr_pages * sizeof(*pin->pages));
        scif_free(pin, sizeof(*pin));
        return 0;
}

/*
 * scif_create_window:
 * @ep: end point
 * @nr_pages: number of pages
 * @offset: registration offset
 * @temp: true if a temporary window is being created
 *
 * Allocate and prepare a self registration window.
 */
struct scif_window *scif_create_window(struct scif_endpt *ep, int nr_pages,
                                       s64 offset, bool temp)
{
        struct scif_window *window;

        might_sleep();
        window = scif_zalloc(sizeof(*window));
        if (!window)
                goto error;

        window->dma_addr = scif_zalloc(nr_pages * sizeof(*window->dma_addr));
        if (!window->dma_addr)
                goto error_free_window;

        window->num_pages = scif_zalloc(nr_pages * sizeof(*window->num_pages));
        if (!window->num_pages)
                goto error_free_window;

        window->offset = offset;
        window->ep = (u64)ep;
        window->magic = SCIFEP_MAGIC;
        window->reg_state = OP_IDLE;
        init_waitqueue_head(&window->regwq);
        window->unreg_state = OP_IDLE;
        init_waitqueue_head(&window->unregwq);
        INIT_LIST_HEAD(&window->list);
        window->type = SCIF_WINDOW_SELF;
        window->temp = temp;
        return window;

error_free_window:
        scif_free(window->dma_addr,
                  nr_pages * sizeof(*window->dma_addr));
        scif_free(window, sizeof(*window));
error:
        return NULL;
}

/**
 * scif_destroy_incomplete_window:
 * @ep: end point
 * @window: registration window
 *
 * Deallocate resources for self window.
 */
static void scif_destroy_incomplete_window(struct scif_endpt *ep,
                                           struct scif_window *window)
{
        int err;
        int nr_pages = window->nr_pages;
        struct scif_allocmsg *alloc = &window->alloc_handle;
        struct scifmsg msg;

retry:
        /* Wait for a SCIF_ALLOC_GNT/REJ message */
        err = wait_event_timeout(alloc->allocwq,
                                 alloc->state != OP_IN_PROGRESS,
                                 SCIF_NODE_ALIVE_TIMEOUT);
        if (!err && scifdev_alive(ep))
                goto retry;

        mutex_lock(&ep->rma_info.rma_lock);
        if (alloc->state == OP_COMPLETED) {
                msg.uop = SCIF_FREE_VIRT;
                msg.src = ep->port;
                msg.payload[0] = ep->remote_ep;
                msg.payload[1] = window->alloc_handle.vaddr;
                msg.payload[2] = (u64)window;
                msg.payload[3] = SCIF_REGISTER;
                _scif_nodeqp_send(ep->remote_dev, &msg);
        }
        mutex_unlock(&ep->rma_info.rma_lock);

        scif_free_window_offset(ep, window, window->offset);
        scif_free(window->dma_addr, nr_pages * sizeof(*window->dma_addr));
        scif_free(window->num_pages, nr_pages * sizeof(*window->num_pages));
        scif_free(window, sizeof(*window));
}

/**
 * scif_unmap_window:
 * @remote_dev: SCIF remote device
 * @window: registration window
 *
 * Delete any DMA mappings created for a registered self window
 */
void scif_unmap_window(struct scif_dev *remote_dev, struct scif_window *window)
{
        int j;

        if (scif_is_iommu_enabled() && !scifdev_self(remote_dev)) {
                if (window->st) {
                        dma_unmap_sg(&remote_dev->sdev->dev,
                                     window->st->sgl, window->st->nents,
                                     DMA_BIDIRECTIONAL);
                        sg_free_table(window->st);
                        kfree(window->st);
                        window->st = NULL;
                }
        } else {
                for (j = 0; j < window->nr_contig_chunks; j++) {
                        if (window->dma_addr[j]) {
                                scif_unmap_single(window->dma_addr[j],
                                                  remote_dev,
                                                  window->num_pages[j] <<
                                                  PAGE_SHIFT);
                                window->dma_addr[j] = 0x0;
                        }
                }
        }
}

static inline struct mm_struct *__scif_acquire_mm(void)
{
        if (scif_ulimit_check)
                return get_task_mm(current);
        return NULL;
}

static inline void __scif_release_mm(struct mm_struct *mm)
{
        if (mm)
                mmput(mm);
}

static inline int
__scif_dec_pinned_vm_lock(struct mm_struct *mm,
                          int nr_pages, bool try_lock)
{
        if (!mm || !nr_pages || !scif_ulimit_check)
                return 0;
        if (try_lock) {
                if (!down_write_trylock(&mm->mmap_sem)) {
                        dev_err(scif_info.mdev.this_device,
                                "%s %d err\n", __func__, __LINE__);
                        return -1;
                }
        } else {
                down_write(&mm->mmap_sem);
        }
        mm->pinned_vm -= nr_pages;
        up_write(&mm->mmap_sem);
        return 0;
}

static inline int __scif_check_inc_pinned_vm(struct mm_struct *mm,
                                             int nr_pages)
{
        unsigned long locked, lock_limit;

        if (!mm || !nr_pages || !scif_ulimit_check)
                return 0;

        locked = nr_pages;
        locked += mm->pinned_vm;
        lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
        if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) {
                dev_err(scif_info.mdev.this_device,
                        "locked(%lu) > lock_limit(%lu)\n",
                        locked, lock_limit);
                return -ENOMEM;
        }
        mm->pinned_vm = locked;
        return 0;
}

/**
 * scif_destroy_window:
 * @ep: end point
 * @window: registration window
 *
 * Deallocate resources for self window.
 */
int scif_destroy_window(struct scif_endpt *ep, struct scif_window *window)
{
        int j;
        struct scif_pinned_pages *pinned_pages = window->pinned_pages;
        int nr_pages = window->nr_pages;

        might_sleep();
        if (!window->temp && window->mm) {
                __scif_dec_pinned_vm_lock(window->mm, window->nr_pages, 0);
                __scif_release_mm(window->mm);
                window->mm = NULL;
        }

        scif_free_window_offset(ep, window, window->offset);
        scif_unmap_window(ep->remote_dev, window);
        /*
         * Decrement references for this set of pinned pages from
         * this window.
         */
        j = atomic_sub_return(1, &pinned_pages->ref_count);
        if (j < 0)
                dev_err(scif_info.mdev.this_device,
                        "%s %d incorrect ref count %d\n",
                        __func__, __LINE__, j);
        /*
         * If the ref count for pinned_pages is zero then someone
         * has already called scif_unpin_pages() for it and we should
         * destroy the page cache.
         */
        if (!j)
                scif_destroy_pinned_pages(window->pinned_pages);
        scif_free(window->dma_addr, nr_pages * sizeof(*window->dma_addr));
        scif_free(window->num_pages, nr_pages * sizeof(*window->num_pages));
        window->magic = 0;
        scif_free(window, sizeof(*window));
        return 0;
}

/**
 * scif_create_remote_lookup:
 * @remote_dev: SCIF remote device
 * @window: remote window
 *
 * Allocate and prepare lookup entries for the remote
 * end to copy over the physical addresses.
 * Returns 0 on success and appropriate errno on failure.
 */
static int scif_create_remote_lookup(struct scif_dev *remote_dev,
                                     struct scif_window *window)
{
        int i, j, err = 0;
        int nr_pages = window->nr_pages;
        bool vmalloc_dma_phys, vmalloc_num_pages;

        might_sleep();
        /* Map window */
        err = scif_map_single(&window->mapped_offset,
                              window, remote_dev, sizeof(*window));
        if (err)
                goto error_window;

        /* Compute the number of lookup entries. 21 == 2MB Shift */
        window->nr_lookup = ALIGN(nr_pages * PAGE_SIZE,
                                        ((2) * 1024 * 1024)) >> 21;

        window->dma_addr_lookup.lookup =
                scif_alloc_coherent(&window->dma_addr_lookup.offset,
                                    remote_dev, window->nr_lookup *
                                    sizeof(*window->dma_addr_lookup.lookup),
                                    GFP_KERNEL | __GFP_ZERO);
        if (!window->dma_addr_lookup.lookup) {
                err = -ENOMEM;
                goto error_window;
        }

        window->num_pages_lookup.lookup =
                scif_alloc_coherent(&window->num_pages_lookup.offset,
                                    remote_dev, window->nr_lookup *
                                    sizeof(*window->num_pages_lookup.lookup),
                                    GFP_KERNEL | __GFP_ZERO);
        if (!window->num_pages_lookup.lookup) {
                err = -ENOMEM;
                goto error_window;
        }

        vmalloc_dma_phys = is_vmalloc_addr(&window->dma_addr[0]);
        vmalloc_num_pages = is_vmalloc_addr(&window->num_pages[0]);

        /* Now map each of the pages containing physical addresses */
        for (i = 0, j = 0; i < nr_pages; i += SCIF_NR_ADDR_IN_PAGE, j++) {
                err = scif_map_page(&window->dma_addr_lookup.lookup[j],
                                    vmalloc_dma_phys ?
                                    vmalloc_to_page(&window->dma_addr[i]) :
                                    virt_to_page(&window->dma_addr[i]),
                                    remote_dev);
                if (err)
                        goto error_window;
                err = scif_map_page(&window->num_pages_lookup.lookup[j],
                                    vmalloc_dma_phys ?
                                    vmalloc_to_page(&window->num_pages[i]) :
                                    virt_to_page(&window->num_pages[i]),
                                    remote_dev);
                if (err)
                        goto error_window;
        }
        return 0;
error_window:
        return err;
}

/**
 * scif_destroy_remote_lookup:
 * @remote_dev: SCIF remote device
 * @window: remote window
 *
 * Destroy lookup entries used for the remote
 * end to copy over the physical addresses.
 */
static void scif_destroy_remote_lookup(struct scif_dev *remote_dev,
                                       struct scif_window *window)
{
        int i, j;

        if (window->nr_lookup) {
                struct scif_rma_lookup *lup = &window->dma_addr_lookup;
                struct scif_rma_lookup *npup = &window->num_pages_lookup;

                for (i = 0, j = 0; i < window->nr_pages;
                        i += SCIF_NR_ADDR_IN_PAGE, j++) {
                        if (lup->lookup && lup->lookup[j])
                                scif_unmap_single(lup->lookup[j],
                                                  remote_dev,
                                                  PAGE_SIZE);
                        if (npup->lookup && npup->lookup[j])
                                scif_unmap_single(npup->lookup[j],
                                                  remote_dev,
                                                  PAGE_SIZE);
                }
                if (lup->lookup)
                        scif_free_coherent(lup->lookup, lup->offset,
                                           remote_dev, window->nr_lookup *
                                           sizeof(*lup->lookup));
                if (npup->lookup)
                        scif_free_coherent(npup->lookup, npup->offset,
                                           remote_dev, window->nr_lookup *
                                           sizeof(*npup->lookup));
                if (window->mapped_offset)
                        scif_unmap_single(window->mapped_offset,
                                          remote_dev, sizeof(*window));
                window->nr_lookup = 0;
        }
}

/**
 * scif_create_remote_window:
 * @ep: end point
 * @nr_pages: number of pages in window
 *
 * Allocate and prepare a remote registration window.
 */
static struct scif_window *
scif_create_remote_window(struct scif_dev *scifdev, int nr_pages)
{
        struct scif_window *window;

        might_sleep();
        window = scif_zalloc(sizeof(*window));
        if (!window)
                goto error_ret;

        window->magic = SCIFEP_MAGIC;
        window->nr_pages = nr_pages;

        window->dma_addr = scif_zalloc(nr_pages * sizeof(*window->dma_addr));
        if (!window->dma_addr)
                goto error_window;

        window->num_pages = scif_zalloc(nr_pages *
                                        sizeof(*window->num_pages));
        if (!window->num_pages)
                goto error_window;

        if (scif_create_remote_lookup(scifdev, window))
                goto error_window;

        window->type = SCIF_WINDOW_PEER;
        window->unreg_state = OP_IDLE;
        INIT_LIST_HEAD(&window->list);
        return window;
error_window:
        scif_destroy_remote_window(window);
error_ret:
        return NULL;
}

/**
 * scif_destroy_remote_window:
 * @ep: end point
 * @window: remote registration window
 *
 * Deallocate resources for remote window.
 */
void
scif_destroy_remote_window(struct scif_window *window)
{
        scif_free(window->dma_addr, window->nr_pages *
                  sizeof(*window->dma_addr));
        scif_free(window->num_pages, window->nr_pages *
                  sizeof(*window->num_pages));
        window->magic = 0;
        scif_free(window, sizeof(*window));
}

/**
 * scif_iommu_map: create DMA mappings if the IOMMU is enabled
 * @remote_dev: SCIF remote device
 * @window: remote registration window
 *
 * Map the physical pages using dma_map_sg(..) and then detect the number
 * of contiguous DMA mappings allocated
 */
static int scif_iommu_map(struct scif_dev *remote_dev,
                          struct scif_window *window)
{
        struct scatterlist *sg;
        int i, err;
        scif_pinned_pages_t pin = window->pinned_pages;

        window->st = kzalloc(sizeof(*window->st), GFP_KERNEL);
        if (!window->st)
                return -ENOMEM;

        err = sg_alloc_table(window->st, window->nr_pages, GFP_KERNEL);
        if (err)
                return err;

        for_each_sg(window->st->sgl, sg, window->st->nents, i)
                sg_set_page(sg, pin->pages[i], PAGE_SIZE, 0x0);

        err = dma_map_sg(&remote_dev->sdev->dev, window->st->sgl,
                         window->st->nents, DMA_BIDIRECTIONAL);
        if (!err)
                return -ENOMEM;
        /* Detect contiguous ranges of DMA mappings */
        sg = window->st->sgl;
        for (i = 0; sg; i++) {
                dma_addr_t last_da;

                window->dma_addr[i] = sg_dma_address(sg);
                window->num_pages[i] = sg_dma_len(sg) >> PAGE_SHIFT;
                last_da = sg_dma_address(sg) + sg_dma_len(sg);
                while ((sg = sg_next(sg)) && sg_dma_address(sg) == last_da) {
                        window->num_pages[i] +=
                                (sg_dma_len(sg) >> PAGE_SHIFT);
                        last_da = window->dma_addr[i] +
                                sg_dma_len(sg);
                }
                window->nr_contig_chunks++;
        }
        return 0;
}

/**
 * scif_map_window:
 * @remote_dev: SCIF remote device
 * @window: self registration window
 *
 * Map pages of a window into the aperture/PCI.
 * Also determine addresses required for DMA.
 */
int
scif_map_window(struct scif_dev *remote_dev, struct scif_window *window)
{
        int i, j, k, err = 0, nr_contig_pages;
        scif_pinned_pages_t pin;
        phys_addr_t phys_prev, phys_curr;

        might_sleep();

        pin = window->pinned_pages;

        if (intel_iommu_enabled && !scifdev_self(remote_dev))
                return scif_iommu_map(remote_dev, window);

        for (i = 0, j = 0; i < window->nr_pages; i += nr_contig_pages, j++) {
                phys_prev = page_to_phys(pin->pages[i]);
                nr_contig_pages = 1;

                /* Detect physically contiguous chunks */
                for (k = i + 1; k < window->nr_pages; k++) {
                        phys_curr = page_to_phys(pin->pages[k]);
                        if (phys_curr != (phys_prev + PAGE_SIZE))
                                break;
                        phys_prev = phys_curr;
                        nr_contig_pages++;
                }
                window->num_pages[j] = nr_contig_pages;
                window->nr_contig_chunks++;
                if (scif_is_mgmt_node()) {
                        /*
                         * Management node has to deal with SMPT on X100 and
                         * hence the DMA mapping is required
                         */
                        err = scif_map_single(&window->dma_addr[j],
                                              phys_to_virt(page_to_phys(
                                                           pin->pages[i])),
                                              remote_dev,
                                              nr_contig_pages << PAGE_SHIFT);
                        if (err)
                                return err;
                } else {
                        window->dma_addr[j] = page_to_phys(pin->pages[i]);
                }
        }
        return err;
}

/**
 * scif_send_scif_unregister:
 * @ep: end point
 * @window: self registration window
 *
 * Send a SCIF_UNREGISTER message.
 */
static int scif_send_scif_unregister(struct scif_endpt *ep,
                                     struct scif_window *window)
{
        struct scifmsg msg;

        msg.uop = SCIF_UNREGISTER;
        msg.src = ep->port;
        msg.payload[0] = window->alloc_handle.vaddr;
        msg.payload[1] = (u64)window;
        return scif_nodeqp_send(ep->remote_dev, &msg);
}

/**
 * scif_unregister_window:
 * @window: self registration window
 *
 * Send an unregistration request and wait for a response.
 */
int scif_unregister_window(struct scif_window *window)
{
        int err = 0;
        struct scif_endpt *ep = (struct scif_endpt *)window->ep;
        bool send_msg = false;

        might_sleep();
        switch (window->unreg_state) {
        case OP_IDLE:
        {
                window->unreg_state = OP_IN_PROGRESS;
                send_msg = true;
                /* fall through */
        }
        case OP_IN_PROGRESS:
        {
                scif_get_window(window, 1);
                mutex_unlock(&ep->rma_info.rma_lock);
                if (send_msg) {
                        err = scif_send_scif_unregister(ep, window);
                        if (err) {
                                window->unreg_state = OP_COMPLETED;
                                goto done;
                        }
                } else {
                        /* Return ENXIO since unregistration is in progress */
                        mutex_lock(&ep->rma_info.rma_lock);
                        return -ENXIO;
                }
retry:
                /* Wait for a SCIF_UNREGISTER_(N)ACK message */
                err = wait_event_timeout(window->unregwq,
                                         window->unreg_state != OP_IN_PROGRESS,
                                         SCIF_NODE_ALIVE_TIMEOUT);
                if (!err && scifdev_alive(ep))
                        goto retry;
                if (!err) {
                        err = -ENODEV;
                        window->unreg_state = OP_COMPLETED;
                        dev_err(scif_info.mdev.this_device,
                                "%s %d err %d\n", __func__, __LINE__, err);
                }
                if (err > 0)
                        err = 0;
done:
                mutex_lock(&ep->rma_info.rma_lock);
                scif_put_window(window, 1);
                break;
        }
        case OP_FAILED:
        {
                if (!scifdev_alive(ep)) {
                        err = -ENODEV;
                        window->unreg_state = OP_COMPLETED;
                }
                break;
        }
        case OP_COMPLETED:
                break;
        default:
                err = -ENODEV;
        }

        if (window->unreg_state == OP_COMPLETED && window->ref_count)
                scif_put_window(window, window->nr_pages);

        if (!window->ref_count) {
                atomic_inc(&ep->rma_info.tw_refcount);
                list_del_init(&window->list);
                scif_free_window_offset(ep, window, window->offset);
                mutex_unlock(&ep->rma_info.rma_lock);
                if ((!!(window->pinned_pages->map_flags & SCIF_MAP_KERNEL)) &&
                    scifdev_alive(ep)) {
                        scif_drain_dma_intr(ep->remote_dev->sdev,
                                            ep->rma_info.dma_chan);
                } else {
                        if (!__scif_dec_pinned_vm_lock(window->mm,
                                                       window->nr_pages, 1)) {
                                __scif_release_mm(window->mm);
                                window->mm = NULL;
                        }
                }
                scif_queue_for_cleanup(window, &scif_info.rma);
                mutex_lock(&ep->rma_info.rma_lock);
        }
        return err;
}

/**
 * scif_send_alloc_request:
 * @ep: end point
 * @window: self registration window
 *
 * Send a remote window allocation request
 */
static int scif_send_alloc_request(struct scif_endpt *ep,
                                   struct scif_window *window)
{
        struct scifmsg msg;
        struct scif_allocmsg *alloc = &window->alloc_handle;

        /* Set up the Alloc Handle */
        alloc->state = OP_IN_PROGRESS;
        init_waitqueue_head(&alloc->allocwq);

        /* Send out an allocation request */
        msg.uop = SCIF_ALLOC_REQ;
        msg.payload[1] = window->nr_pages;
        msg.payload[2] = (u64)&window->alloc_handle;
        return _scif_nodeqp_send(ep->remote_dev, &msg);
}

/**
 * scif_prep_remote_window:
 * @ep: end point
 * @window: self registration window
 *
 * Send a remote window allocation request, wait for an allocation response,
 * and prepares the remote window by copying over the page lists
 */
static int scif_prep_remote_window(struct scif_endpt *ep,
                                   struct scif_window *window)
{
        struct scifmsg msg;
        struct scif_window *remote_window;
        struct scif_allocmsg *alloc = &window->alloc_handle;
        dma_addr_t *dma_phys_lookup, *tmp, *num_pages_lookup, *tmp1;
        int i = 0, j = 0;
        int nr_contig_chunks, loop_nr_contig_chunks;
        int remaining_nr_contig_chunks, nr_lookup;
        int err, map_err;

        map_err = scif_map_window(ep->remote_dev, window);
        if (map_err)
                dev_err(&ep->remote_dev->sdev->dev,
                        "%s %d map_err %d\n", __func__, __LINE__, map_err);
        remaining_nr_contig_chunks = window->nr_contig_chunks;
        nr_contig_chunks = window->nr_contig_chunks;
retry:
        /* Wait for a SCIF_ALLOC_GNT/REJ message */
        err = wait_event_timeout(alloc->allocwq,
                                 alloc->state != OP_IN_PROGRESS,
                                 SCIF_NODE_ALIVE_TIMEOUT);
        mutex_lock(&ep->rma_info.rma_lock);
        /* Synchronize with the thread waking up allocwq */
        mutex_unlock(&ep->rma_info.rma_lock);
        if (!err && scifdev_alive(ep))
                goto retry;

        if (!err)
                err = -ENODEV;

        if (err > 0)
                err = 0;
        else
                return err;

        /* Bail out. The remote end rejected this request */
        if (alloc->state == OP_FAILED)
                return -ENOMEM;

        if (map_err) {
                dev_err(&ep->remote_dev->sdev->dev,
                        "%s %d err %d\n", __func__, __LINE__, map_err);
                msg.uop = SCIF_FREE_VIRT;
                msg.src = ep->port;
                msg.payload[0] = ep->remote_ep;
                msg.payload[1] = window->alloc_handle.vaddr;
                msg.payload[2] = (u64)window;
                msg.payload[3] = SCIF_REGISTER;
                spin_lock(&ep->lock);
                if (ep->state == SCIFEP_CONNECTED)
                        err = _scif_nodeqp_send(ep->remote_dev, &msg);
                else
                        err = -ENOTCONN;
                spin_unlock(&ep->lock);
                return err;
        }

        remote_window = scif_ioremap(alloc->phys_addr, sizeof(*window),
                                     ep->remote_dev);

        /* Compute the number of lookup entries. 21 == 2MB Shift */
        nr_lookup = ALIGN(nr_contig_chunks, SCIF_NR_ADDR_IN_PAGE)
                          >> ilog2(SCIF_NR_ADDR_IN_PAGE);

        dma_phys_lookup =
                scif_ioremap(remote_window->dma_addr_lookup.offset,
                             nr_lookup *
                             sizeof(*remote_window->dma_addr_lookup.lookup),
                             ep->remote_dev);
        num_pages_lookup =
                scif_ioremap(remote_window->num_pages_lookup.offset,
                             nr_lookup *
                             sizeof(*remote_window->num_pages_lookup.lookup),
                             ep->remote_dev);

        while (remaining_nr_contig_chunks) {
                loop_nr_contig_chunks = min_t(int, remaining_nr_contig_chunks,
                                              (int)SCIF_NR_ADDR_IN_PAGE);
                /* #1/2 - Copy  physical addresses over to the remote side */

                /* #2/2 - Copy DMA addresses (addresses that are fed into the
                 * DMA engine) We transfer bus addresses which are then
                 * converted into a MIC physical address on the remote
                 * side if it is a MIC, if the remote node is a mgmt node we
                 * transfer the MIC physical address
                 */
                tmp = scif_ioremap(dma_phys_lookup[j],
                                   loop_nr_contig_chunks *
                                   sizeof(*window->dma_addr),
                                   ep->remote_dev);
                tmp1 = scif_ioremap(num_pages_lookup[j],
                                    loop_nr_contig_chunks *
                                    sizeof(*window->num_pages),
                                    ep->remote_dev);
                if (scif_is_mgmt_node()) {
                        memcpy_toio((void __force __iomem *)tmp,
                                    &window->dma_addr[i], loop_nr_contig_chunks
                                    * sizeof(*window->dma_addr));
                        memcpy_toio((void __force __iomem *)tmp1,
                                    &window->num_pages[i], loop_nr_contig_chunks
                                    * sizeof(*window->num_pages));
                } else {
                        if (scifdev_is_p2p(ep->remote_dev)) {
                                /*
                                 * add remote node's base address for this node
                                 * to convert it into a MIC address
                                 */
                                int m;
                                dma_addr_t dma_addr;

                                for (m = 0; m < loop_nr_contig_chunks; m++) {
                                        dma_addr = window->dma_addr[i + m] +
                                                ep->remote_dev->base_addr;
                                        writeq(dma_addr,
                                               (void __force __iomem *)&tmp[m]);
                                }
                                memcpy_toio((void __force __iomem *)tmp1,
                                            &window->num_pages[i],
                                            loop_nr_contig_chunks
                                            * sizeof(*window->num_pages));
                        } else {
                                /* Mgmt node or loopback - transfer DMA
                                 * addresses as is, this is the same as a
                                 * MIC physical address (we use the dma_addr
                                 * and not the phys_addr array since the
                                 * phys_addr is only setup if there is a mmap()
                                 * request from the mgmt node)
                                 */
                                memcpy_toio((void __force __iomem *)tmp,
                                            &window->dma_addr[i],
                                            loop_nr_contig_chunks *
                                            sizeof(*window->dma_addr));
                                memcpy_toio((void __force __iomem *)tmp1,
                                            &window->num_pages[i],
                                            loop_nr_contig_chunks *
                                            sizeof(*window->num_pages));
                        }
                }
                remaining_nr_contig_chunks -= loop_nr_contig_chunks;
                i += loop_nr_contig_chunks;
                j++;
                scif_iounmap(tmp, loop_nr_contig_chunks *
                             sizeof(*window->dma_addr), ep->remote_dev);
                scif_iounmap(tmp1, loop_nr_contig_chunks *
                             sizeof(*window->num_pages), ep->remote_dev);
        }

        /* Prepare the remote window for the peer */
        remote_window->peer_window = (u64)window;
        remote_window->offset = window->offset;
        remote_window->prot = window->prot;
        remote_window->nr_contig_chunks = nr_contig_chunks;
        remote_window->ep = ep->remote_ep;
        scif_iounmap(num_pages_lookup,
                     nr_lookup *
                     sizeof(*remote_window->num_pages_lookup.lookup),
                     ep->remote_dev);
        scif_iounmap(dma_phys_lookup,
                     nr_lookup *
                     sizeof(*remote_window->dma_addr_lookup.lookup),
                     ep->remote_dev);
        scif_iounmap(remote_window, sizeof(*remote_window), ep->remote_dev);
        window->peer_window = alloc->vaddr;
        return err;
}

/**
 * scif_send_scif_register:
 * @ep: end point
 * @window: self registration window
 *
 * Send a SCIF_REGISTER message if EP is connected and wait for a
 * SCIF_REGISTER_(N)ACK message else send a SCIF_FREE_VIRT
 * message so that the peer can free its remote window allocated earlier.
 */
static int scif_send_scif_register(struct scif_endpt *ep,
                                   struct scif_window *window)
{
        int err = 0;
        struct scifmsg msg;

        msg.src = ep->port;
        msg.payload[0] = ep->remote_ep;
        msg.payload[1] = window->alloc_handle.vaddr;
        msg.payload[2] = (u64)window;
        spin_lock(&ep->lock);
        if (ep->state == SCIFEP_CONNECTED) {
                msg.uop = SCIF_REGISTER;
                window->reg_state = OP_IN_PROGRESS;
                err = _scif_nodeqp_send(ep->remote_dev, &msg);
                spin_unlock(&ep->lock);
                if (!err) {
retry:
                        /* Wait for a SCIF_REGISTER_(N)ACK message */
                        err = wait_event_timeout(window->regwq,
                                                 window->reg_state !=
                                                 OP_IN_PROGRESS,
                                                 SCIF_NODE_ALIVE_TIMEOUT);
                        if (!err && scifdev_alive(ep))
                                goto retry;
                        err = !err ? -ENODEV : 0;
                        if (window->reg_state == OP_FAILED)
                                err = -ENOTCONN;
                }
        } else {
                msg.uop = SCIF_FREE_VIRT;
                msg.payload[3] = SCIF_REGISTER;
                err = _scif_nodeqp_send(ep->remote_dev, &msg);
                spin_unlock(&ep->lock);
                if (!err)
                        err = -ENOTCONN;
        }
        return err;
}

/**
 * scif_get_window_offset:
 * @ep: end point descriptor
 * @flags: flags
 * @offset: offset hint
 * @num_pages: number of pages
 * @out_offset: computed offset returned by reference.
 *
 * Compute/Claim a new offset for this EP.
 */
int scif_get_window_offset(struct scif_endpt *ep, int flags, s64 offset,
                           int num_pages, s64 *out_offset)
{
        s64 page_index;
        struct iova *iova_ptr;
        int err = 0;

        if (flags & SCIF_MAP_FIXED) {
                page_index = SCIF_IOVA_PFN(offset);
                iova_ptr = reserve_iova(&ep->rma_info.iovad, page_index,
                                        page_index + num_pages - 1);
                if (!iova_ptr)
                        err = -EADDRINUSE;
        } else {
                iova_ptr = alloc_iova(&ep->rma_info.iovad, num_pages,
                                      SCIF_DMA_63BIT_PFN - 1, 0);
                if (!iova_ptr)
                        err = -ENOMEM;
        }
        if (!err)
                *out_offset = (iova_ptr->pfn_lo) << PAGE_SHIFT;
        return err;
}

/**
 * scif_free_window_offset:
 * @ep: end point descriptor
 * @window: registration window
 * @offset: Offset to be freed
 *
 * Free offset for this EP. The callee is supposed to grab
 * the RMA mutex before calling this API.
 */
void scif_free_window_offset(struct scif_endpt *ep,
                             struct scif_window *window, s64 offset)
{
        if ((window && !window->offset_freed) || !window) {
                free_iova(&ep->rma_info.iovad, offset >> PAGE_SHIFT);
                if (window)
                        window->offset_freed = true;
        }
}

/**
 * scif_alloc_req: Respond to SCIF_ALLOC_REQ interrupt message
 * @msg:        Interrupt message
 *
 * Remote side is requesting a memory allocation.
 */
void scif_alloc_req(struct scif_dev *scifdev, struct scifmsg *msg)
{
        int err;
        struct scif_window *window = NULL;
        int nr_pages = msg->payload[1];

        window = scif_create_remote_window(scifdev, nr_pages);
        if (!window) {
                err = -ENOMEM;
                goto error;
        }

        /* The peer's allocation request is granted */
        msg->uop = SCIF_ALLOC_GNT;
        msg->payload[0] = (u64)window;
        msg->payload[1] = window->mapped_offset;
        err = scif_nodeqp_send(scifdev, msg);
        if (err)
                scif_destroy_remote_window(window);
        return;
error:
        /* The peer's allocation request is rejected */
        dev_err(&scifdev->sdev->dev,
                "%s %d error %d alloc_ptr %p nr_pages 0x%x\n",
                __func__, __LINE__, err, window, nr_pages);
        msg->uop = SCIF_ALLOC_REJ;
        scif_nodeqp_send(scifdev, msg);
}

/**
 * scif_alloc_gnt_rej: Respond to SCIF_ALLOC_GNT/REJ interrupt message
 * @msg:        Interrupt message
 *
 * Remote side responded to a memory allocation.
 */
void scif_alloc_gnt_rej(struct scif_dev *scifdev, struct scifmsg *msg)
{
        struct scif_allocmsg *handle = (struct scif_allocmsg *)msg->payload[2];
        struct scif_window *window = container_of(handle, struct scif_window,
                                                  alloc_handle);
        struct scif_endpt *ep = (struct scif_endpt *)window->ep;

        mutex_lock(&ep->rma_info.rma_lock);
        handle->vaddr = msg->payload[0];
        handle->phys_addr = msg->payload[1];
        if (msg->uop == SCIF_ALLOC_GNT)
                handle->state = OP_COMPLETED;
        else
                handle->state = OP_FAILED;
        wake_up(&handle->allocwq);
        mutex_unlock(&ep->rma_info.rma_lock);
}

/**
 * scif_free_virt: Respond to SCIF_FREE_VIRT interrupt message
 * @msg:        Interrupt message
 *
 * Free up memory kmalloc'd earlier.
 */
void scif_free_virt(struct scif_dev *scifdev, struct scifmsg *msg)
{
        struct scif_window *window = (struct scif_window *)msg->payload[1];

        scif_destroy_remote_window(window);
}

static void
scif_fixup_aper_base(struct scif_dev *dev, struct scif_window *window)
{
        int j;
        struct scif_hw_dev *sdev = dev->sdev;
        phys_addr_t apt_base = 0;

        /*
         * Add the aperture base if the DMA address is not card relative
         * since the DMA addresses need to be an offset into the bar
         */
        if (!scifdev_self(dev) && window->type == SCIF_WINDOW_PEER &&
            sdev->aper && !sdev->card_rel_da)
                apt_base = sdev->aper->pa;
        else
                return;

        for (j = 0; j < window->nr_contig_chunks; j++) {
                if (window->num_pages[j])
                        window->dma_addr[j] += apt_base;
                else
                        break;
        }
}

/**
 * scif_recv_reg: Respond to SCIF_REGISTER interrupt message
 * @msg:        Interrupt message
 *
 * Update remote window list with a new registered window.
 */
void scif_recv_reg(struct scif_dev *scifdev, struct scifmsg *msg)
{
        struct scif_endpt *ep = (struct scif_endpt *)msg->payload[0];
        struct scif_window *window =
                (struct scif_window *)msg->payload[1];

        mutex_lock(&ep->rma_info.rma_lock);
        spin_lock(&ep->lock);
        if (ep->state == SCIFEP_CONNECTED) {
                msg->uop = SCIF_REGISTER_ACK;
                scif_nodeqp_send(ep->remote_dev, msg);
                scif_fixup_aper_base(ep->remote_dev, window);
                /* No further failures expected. Insert new window */
                scif_insert_window(window, &ep->rma_info.remote_reg_list);
        } else {
                msg->uop = SCIF_REGISTER_NACK;
                scif_nodeqp_send(ep->remote_dev, msg);
        }
        spin_unlock(&ep->lock);
        mutex_unlock(&ep->rma_info.rma_lock);
        /* free up any lookup resources now that page lists are transferred */
        scif_destroy_remote_lookup(ep->remote_dev, window);
        /*
         * We could not insert the window but we need to
         * destroy the window.
         */
        if (msg->uop == SCIF_REGISTER_NACK)
                scif_destroy_remote_window(window);
}

/**
 * scif_recv_unreg: Respond to SCIF_UNREGISTER interrupt message
 * @msg:        Interrupt message
 *
 * Remove window from remote registration list;
 */
void scif_recv_unreg(struct scif_dev *scifdev, struct scifmsg *msg)
{
        struct scif_rma_req req;
        struct scif_window *window = NULL;
        struct scif_window *recv_window =
                (struct scif_window *)msg->payload[0];
        struct scif_endpt *ep;
        int del_window = 0;

        ep = (struct scif_endpt *)recv_window->ep;
        req.out_window = &window;
        req.offset = recv_window->offset;
        req.prot = 0;
        req.nr_bytes = recv_window->nr_pages << PAGE_SHIFT;
        req.type = SCIF_WINDOW_FULL;
        req.head = &ep->rma_info.remote_reg_list;
        msg->payload[0] = ep->remote_ep;

        mutex_lock(&ep->rma_info.rma_lock);
        /* Does a valid window exist? */
        if (scif_query_window(&req)) {
                dev_err(&scifdev->sdev->dev,
                        "%s %d -ENXIO\n", __func__, __LINE__);
                msg->uop = SCIF_UNREGISTER_ACK;
                goto error;
        }
        if (window) {
                if (window->ref_count)
                        scif_put_window(window, window->nr_pages);
                else
                        dev_err(&scifdev->sdev->dev,
                                "%s %d ref count should be +ve\n",
                                __func__, __LINE__);
                window->unreg_state = OP_COMPLETED;
                if (!window->ref_count) {
                        msg->uop = SCIF_UNREGISTER_ACK;
                        atomic_inc(&ep->rma_info.tw_refcount);
                        ep->rma_info.async_list_del = 1;
                        list_del_init(&window->list);
                        del_window = 1;
                } else {
                        /* NACK! There are valid references to this window */
                        msg->uop = SCIF_UNREGISTER_NACK;
                }
        } else {
                /* The window did not make its way to the list at all. ACK */
                msg->uop = SCIF_UNREGISTER_ACK;
                scif_destroy_remote_window(recv_window);
        }
error:
        mutex_unlock(&ep->rma_info.rma_lock);
        if (del_window)
                scif_drain_dma_intr(ep->remote_dev->sdev,
                                    ep->rma_info.dma_chan);
        scif_nodeqp_send(ep->remote_dev, msg);
        if (del_window)
                scif_queue_for_cleanup(window, &scif_info.rma);
}

/**
 * scif_recv_reg_ack: Respond to SCIF_REGISTER_ACK interrupt message
 * @msg:        Interrupt message
 *
 * Wake up the window waiting to complete registration.
 */
void scif_recv_reg_ack(struct scif_dev *scifdev, struct scifmsg *msg)
{
        struct scif_window *window =
                (struct scif_window *)msg->payload[2];
        struct scif_endpt *ep = (struct scif_endpt *)window->ep;

        mutex_lock(&ep->rma_info.rma_lock);
        window->reg_state = OP_COMPLETED;
        wake_up(&window->regwq);
        mutex_unlock(&ep->rma_info.rma_lock);
}

/**
 * scif_recv_reg_nack: Respond to SCIF_REGISTER_NACK interrupt message
 * @msg:        Interrupt message
 *
 * Wake up the window waiting to inform it that registration
 * cannot be completed.
 */
void scif_recv_reg_nack(struct scif_dev *scifdev, struct scifmsg *msg)
{
        struct scif_window *window =
                (struct scif_window *)msg->payload[2];
        struct scif_endpt *ep = (struct scif_endpt *)window->ep;

        mutex_lock(&ep->rma_info.rma_lock);
        window->reg_state = OP_FAILED;
        wake_up(&window->regwq);
        mutex_unlock(&ep->rma_info.rma_lock);
}

/**
 * scif_recv_unreg_ack: Respond to SCIF_UNREGISTER_ACK interrupt message
 * @msg:        Interrupt message
 *
 * Wake up the window waiting to complete unregistration.
 */
void scif_recv_unreg_ack(struct scif_dev *scifdev, struct scifmsg *msg)
{
        struct scif_window *window =
                (struct scif_window *)msg->payload[1];
        struct scif_endpt *ep = (struct scif_endpt *)window->ep;

        mutex_lock(&ep->rma_info.rma_lock);
        window->unreg_state = OP_COMPLETED;
        wake_up(&window->unregwq);
        mutex_unlock(&ep->rma_info.rma_lock);
}

/**
 * scif_recv_unreg_nack: Respond to SCIF_UNREGISTER_NACK interrupt message
 * @msg:        Interrupt message
 *
 * Wake up the window waiting to inform it that unregistration
 * cannot be completed immediately.
 */
void scif_recv_unreg_nack(struct scif_dev *scifdev, struct scifmsg *msg)
{
        struct scif_window *window =
                (struct scif_window *)msg->payload[1];
        struct scif_endpt *ep = (struct scif_endpt *)window->ep;

        mutex_lock(&ep->rma_info.rma_lock);
        window->unreg_state = OP_FAILED;
        wake_up(&window->unregwq);
        mutex_unlock(&ep->rma_info.rma_lock);
}

int __scif_pin_pages(void *addr, size_t len, int *out_prot,
                     int map_flags, scif_pinned_pages_t *pages)
{
        struct scif_pinned_pages *pinned_pages;
        int nr_pages, err = 0, i;
        bool vmalloc_addr = false;
        bool try_upgrade = false;
        int prot = *out_prot;
        int ulimit = 0;
        struct mm_struct *mm = NULL;

        /* Unsupported flags */
        if (map_flags & ~(SCIF_MAP_KERNEL | SCIF_MAP_ULIMIT))
                return -EINVAL;
        ulimit = !!(map_flags & SCIF_MAP_ULIMIT);

        /* Unsupported protection requested */
        if (prot & ~(SCIF_PROT_READ | SCIF_PROT_WRITE))
                return -EINVAL;

        /* addr/len must be page aligned. len should be non zero */
        if (!len ||
            (ALIGN((u64)addr, PAGE_SIZE) != (u64)addr) ||
            (ALIGN((u64)len, PAGE_SIZE) != (u64)len))
                return -EINVAL;

        might_sleep();

        nr_pages = len >> PAGE_SHIFT;

        /* Allocate a set of pinned pages */
        pinned_pages = scif_create_pinned_pages(nr_pages, prot);
        if (!pinned_pages)
                return -ENOMEM;

        if (map_flags & SCIF_MAP_KERNEL) {
                if (is_vmalloc_addr(addr))
                        vmalloc_addr = true;

                for (i = 0; i < nr_pages; i++) {
                        if (vmalloc_addr)
                                pinned_pages->pages[i] =
                                        vmalloc_to_page(addr + (i * PAGE_SIZE));
                        else
                                pinned_pages->pages[i] =
                                        virt_to_page(addr + (i * PAGE_SIZE));
                }
                pinned_pages->nr_pages = nr_pages;
                pinned_pages->map_flags = SCIF_MAP_KERNEL;
        } else {
                /*
                 * SCIF supports registration caching. If a registration has
                 * been requested with read only permissions, then we try
                 * to pin the pages with RW permissions so that a subsequent
                 * transfer with RW permission can hit the cache instead of
                 * invalidating it. If the upgrade fails with RW then we
                 * revert back to R permission and retry
                 */
                if (prot == SCIF_PROT_READ)
                        try_upgrade = true;
                prot |= SCIF_PROT_WRITE;
retry:
                mm = current->mm;
                down_write(&mm->mmap_sem);
                if (ulimit) {
                        err = __scif_check_inc_pinned_vm(mm, nr_pages);
                        if (err) {
                                up_write(&mm->mmap_sem);
                                pinned_pages->nr_pages = 0;
                                goto error_unmap;
                        }
                }

                pinned_pages->nr_pages = get_user_pages(
                                (u64)addr,
                                nr_pages,
                                (prot & SCIF_PROT_WRITE) ? FOLL_WRITE : 0,
                                pinned_pages->pages,
                                NULL);
                up_write(&mm->mmap_sem);
                if (nr_pages != pinned_pages->nr_pages) {
                        if (try_upgrade) {
                                if (ulimit)
                                        __scif_dec_pinned_vm_lock(mm,
                                                                  nr_pages, 0);
                                /* Roll back any pinned pages */
                                for (i = 0; i < pinned_pages->nr_pages; i++) {
                                        if (pinned_pages->pages[i])
                                                put_page(
                                                pinned_pages->pages[i]);
                                }
                                prot &= ~SCIF_PROT_WRITE;
                                try_upgrade = false;
                                goto retry;
                        }
                }
                pinned_pages->map_flags = 0;
        }

        if (pinned_pages->nr_pages < nr_pages) {
                err = -EFAULT;
                pinned_pages->nr_pages = nr_pages;
                goto dec_pinned;
        }

        *out_prot = prot;
        atomic_set(&pinned_pages->ref_count, 1);
        *pages = pinned_pages;
        return err;
dec_pinned:
        if (ulimit)
                __scif_dec_pinned_vm_lock(mm, nr_pages, 0);
        /* Something went wrong! Rollback */
error_unmap:
        pinned_pages->nr_pages = nr_pages;
        scif_destroy_pinned_pages(pinned_pages);
        *pages = NULL;
        dev_dbg(scif_info.mdev.this_device,
                "%s %d err %d len 0x%lx\n", __func__, __LINE__, err, len);
        return err;
}

int scif_pin_pages(void *addr, size_t len, int prot,
                   int map_flags, scif_pinned_pages_t *pages)
{
        return __scif_pin_pages(addr, len, &prot, map_flags, pages);
}
EXPORT_SYMBOL_GPL(scif_pin_pages);

int scif_unpin_pages(scif_pinned_pages_t pinned_pages)
{
        int err = 0, ret;

        if (!pinned_pages || SCIFEP_MAGIC != pinned_pages->magic)
                return -EINVAL;

        ret = atomic_sub_return(1, &pinned_pages->ref_count);
        if (ret < 0) {
                dev_err(scif_info.mdev.this_device,
                        "%s %d scif_unpin_pages called without pinning? rc %d\n",
                        __func__, __LINE__, ret);
                return -EINVAL;
        }
        /*
         * Destroy the window if the ref count for this set of pinned
         * pages has dropped to zero. If it is positive then there is
         * a valid registered window which is backed by these pages and
         * it will be destroyed once all such windows are unregistered.
         */
        if (!ret)
                err = scif_destroy_pinned_pages(pinned_pages);

        return err;
}
EXPORT_SYMBOL_GPL(scif_unpin_pages);

static inline void
scif_insert_local_window(struct scif_window *window, struct scif_endpt *ep)
{
        mutex_lock(&ep->rma_info.rma_lock);
        scif_insert_window(window, &ep->rma_info.reg_list);
        mutex_unlock(&ep->rma_info.rma_lock);
}

off_t scif_register_pinned_pages(scif_epd_t epd,
                                 scif_pinned_pages_t pinned_pages,
                                 off_t offset, int map_flags)
{
        struct scif_endpt *ep = (struct scif_endpt *)epd;
        s64 computed_offset;
        struct scif_window *window;
        int err;
        size_t len;
        struct device *spdev;

        /* Unsupported flags */
        if (map_flags & ~SCIF_MAP_FIXED)
                return -EINVAL;

        len = pinned_pages->nr_pages << PAGE_SHIFT;

        /*
         * Offset is not page aligned/negative or offset+len
         * wraps around with SCIF_MAP_FIXED.
         */
        if ((map_flags & SCIF_MAP_FIXED) &&
            ((ALIGN(offset, PAGE_SIZE) != offset) ||
            (offset < 0) ||
            (len > LONG_MAX - offset)))
                return -EINVAL;

        might_sleep();

        err = scif_verify_epd(ep);
        if (err)
                return err;
        /*
         * It is an error to pass pinned_pages to scif_register_pinned_pages()
         * after calling scif_unpin_pages().
         */
        if (!atomic_add_unless(&pinned_pages->ref_count, 1, 0))
                return -EINVAL;

        /* Compute the offset for this registration */
        err = scif_get_window_offset(ep, map_flags, offset,
                                     len, &computed_offset);
        if (err) {
                atomic_sub(1, &pinned_pages->ref_count);
                return err;
        }

        /* Allocate and prepare self registration window */
        window = scif_create_window(ep, pinned_pages->nr_pages,
                                    computed_offset, false);
        if (!window) {
                atomic_sub(1, &pinned_pages->ref_count);
                scif_free_window_offset(ep, NULL, computed_offset);
                return -ENOMEM;
        }

        window->pinned_pages = pinned_pages;
        window->nr_pages = pinned_pages->nr_pages;
        window->prot = pinned_pages->prot;

        spdev = scif_get_peer_dev(ep->remote_dev);
        if (IS_ERR(spdev)) {
                err = PTR_ERR(spdev);
                scif_destroy_window(ep, window);
                return err;
        }
        err = scif_send_alloc_request(ep, window);
        if (err) {
                dev_err(&ep->remote_dev->sdev->dev,
                        "%s %d err %d\n", __func__, __LINE__, err);
                goto error_unmap;
        }

        /* Prepare the remote registration window */
        err = scif_prep_remote_window(ep, window);
        if (err) {
                dev_err(&ep->remote_dev->sdev->dev,
                        "%s %d err %d\n", __func__, __LINE__, err);
                goto error_unmap;
        }

        /* Tell the peer about the new window */
        err = scif_send_scif_register(ep, window);
        if (err) {
                dev_err(&ep->remote_dev->sdev->dev,
                        "%s %d err %d\n", __func__, __LINE__, err);
                goto error_unmap;
        }

        scif_put_peer_dev(spdev);
        /* No further failures expected. Insert new window */
        scif_insert_local_window(window, ep);
        return computed_offset;
error_unmap:
        scif_destroy_window(ep, window);
        scif_put_peer_dev(spdev);
        dev_err(&ep->remote_dev->sdev->dev,
                "%s %d err %d\n", __func__, __LINE__, err);
        return err;
}
EXPORT_SYMBOL_GPL(scif_register_pinned_pages);

off_t scif_register(scif_epd_t epd, void *addr, size_t len, off_t offset,
                    int prot, int map_flags)
{
        scif_pinned_pages_t pinned_pages;
        off_t err;
        struct scif_endpt *ep = (struct scif_endpt *)epd;
        s64 computed_offset;
        struct scif_window *window;
        struct mm_struct *mm = NULL;
        struct device *spdev;

        dev_dbg(scif_info.mdev.this_device,
                "SCIFAPI register: ep %p addr %p len 0x%lx offset 0x%lx prot 0x%x map_flags 0x%x\n",
                epd, addr, len, offset, prot, map_flags);
        /* Unsupported flags */
        if (map_flags & ~(SCIF_MAP_FIXED | SCIF_MAP_KERNEL))
                return -EINVAL;

        /*
         * Offset is not page aligned/negative or offset+len
         * wraps around with SCIF_MAP_FIXED.
         */
        if ((map_flags & SCIF_MAP_FIXED) &&
            ((ALIGN(offset, PAGE_SIZE) != offset) ||
            (offset < 0) ||
            (len > LONG_MAX - offset)))
                return -EINVAL;

        /* Unsupported protection requested */
        if (prot & ~(SCIF_PROT_READ | SCIF_PROT_WRITE))
                return -EINVAL;

        /* addr/len must be page aligned. len should be non zero */
        if (!len || (ALIGN((u64)addr, PAGE_SIZE) != (u64)addr) ||
            (ALIGN(len, PAGE_SIZE) != len))
                return -EINVAL;

        might_sleep();

        err = scif_verify_epd(ep);
        if (err)
                return err;

        /* Compute the offset for this registration */
        err = scif_get_window_offset(ep, map_flags, offset,
                                     len >> PAGE_SHIFT, &computed_offset);
        if (err)
                return err;

        spdev = scif_get_peer_dev(ep->remote_dev);
        if (IS_ERR(spdev)) {
                err = PTR_ERR(spdev);
                scif_free_window_offset(ep, NULL, computed_offset);
                return err;
        }
        /* Allocate and prepare self registration window */
        window = scif_create_window(ep, len >> PAGE_SHIFT,
                                    computed_offset, false);
        if (!window) {
                scif_free_window_offset(ep, NULL, computed_offset);
                scif_put_peer_dev(spdev);
                return -ENOMEM;
        }

        window->nr_pages = len >> PAGE_SHIFT;

        err = scif_send_alloc_request(ep, window);
        if (err) {
                scif_destroy_incomplete_window(ep, window);
                scif_put_peer_dev(spdev);
                return err;
        }

        if (!(map_flags & SCIF_MAP_KERNEL)) {
                mm = __scif_acquire_mm();
                map_flags |= SCIF_MAP_ULIMIT;
        }
        /* Pin down the pages */
        err = __scif_pin_pages(addr, len, &prot,
                               map_flags & (SCIF_MAP_KERNEL | SCIF_MAP_ULIMIT),
                               &pinned_pages);
        if (err) {
                scif_destroy_incomplete_window(ep, window);
                __scif_release_mm(mm);
                goto error;
        }

        window->pinned_pages = pinned_pages;
        window->prot = pinned_pages->prot;
        window->mm = mm;

        /* Prepare the remote registration window */
        err = scif_prep_remote_window(ep, window);
        if (err) {
                dev_err(&ep->remote_dev->sdev->dev,
                        "%s %d err %ld\n", __func__, __LINE__, err);
                goto error_unmap;
        }

        /* Tell the peer about the new window */
        err = scif_send_scif_register(ep, window);
        if (err) {
                dev_err(&ep->remote_dev->sdev->dev,
                        "%s %d err %ld\n", __func__, __LINE__, err);
                goto error_unmap;
        }

        scif_put_peer_dev(spdev);
        /* No further failures expected. Insert new window */
        scif_insert_local_window(window, ep);
        dev_dbg(&ep->remote_dev->sdev->dev,
                "SCIFAPI register: ep %p addr %p len 0x%lx computed_offset 0x%llx\n",
                epd, addr, len, computed_offset);
        return computed_offset;
error_unmap:
        scif_destroy_window(ep, window);
error:
        scif_put_peer_dev(spdev);
        dev_err(&ep->remote_dev->sdev->dev,
                "%s %d err %ld\n", __func__, __LINE__, err);
        return err;
}
EXPORT_SYMBOL_GPL(scif_register);

int
scif_unregister(scif_epd_t epd, off_t offset, size_t len)
{
        struct scif_endpt *ep = (struct scif_endpt *)epd;
        struct scif_window *window = NULL;
        struct scif_rma_req req;
        int nr_pages, err;
        struct device *spdev;

        dev_dbg(scif_info.mdev.this_device,
                "SCIFAPI unregister: ep %p offset 0x%lx len 0x%lx\n",
                ep, offset, len);
        /* len must be page aligned. len should be non zero */
        if (!len ||
            (ALIGN((u64)len, PAGE_SIZE) != (u64)len))
                return -EINVAL;

        /* Offset is not page aligned or offset+len wraps around */
        if ((ALIGN(offset, PAGE_SIZE) != offset) ||
            (offset < 0) ||
            (len > LONG_MAX - offset))
                return -EINVAL;

        err = scif_verify_epd(ep);
        if (err)
                return err;

        might_sleep();
        nr_pages = len >> PAGE_SHIFT;

        req.out_window = &window;
        req.offset = offset;
        req.prot = 0;
        req.nr_bytes = len;
        req.type = SCIF_WINDOW_FULL;
        req.head = &ep->rma_info.reg_list;

        spdev = scif_get_peer_dev(ep->remote_dev);
        if (IS_ERR(spdev)) {
                err = PTR_ERR(spdev);
                return err;
        }
        mutex_lock(&ep->rma_info.rma_lock);
        /* Does a valid window exist? */
        err = scif_query_window(&req);
        if (err) {
                dev_err(&ep->remote_dev->sdev->dev,
                        "%s %d err %d\n", __func__, __LINE__, err);
                goto error;
        }
        /* Unregister all the windows in this range */
        err = scif_rma_list_unregister(window, offset, nr_pages);
        if (err)
                dev_err(&ep->remote_dev->sdev->dev,
                        "%s %d err %d\n", __func__, __LINE__, err);
error:
        mutex_unlock(&ep->rma_info.rma_lock);
        scif_put_peer_dev(spdev);
        return err;
}
EXPORT_SYMBOL_GPL(scif_unregister);