LXR linux/include/linux/aio.h

   1#ifndef __LINUX__AIO_H
   2#define __LINUX__AIO_H
   3
   4#include <linux/list.h>
   5#include <linux/workqueue.h>
   6#include <linux/aio_abi.h>
   7#include <linux/uio.h>
   8#include <linux/rcupdate.h>
   9
  10#include <linux/atomic.h>
  11
  12struct kioctx;
  13struct kiocb;
  14
  15#define KIOCB_KEY               0
  16
  17/*
  18 * We use ki_cancel == KIOCB_CANCELLED to indicate that a kiocb has been either
  19 * cancelled or completed (this makes a certain amount of sense because
  20 * successful cancellation - io_cancel() - does deliver the completion to
  21 * userspace).
  22 *
  23 * And since most things don't implement kiocb cancellation and we'd really like
  24 * kiocb completion to be lockless when possible, we use ki_cancel to
  25 * synchronize cancellation and completion - we only set it to KIOCB_CANCELLED
  26 * with xchg() or cmpxchg(), see batch_complete_aio() and kiocb_cancel().
  27 */
  28#define KIOCB_CANCELLED         ((void *) (~0ULL))
  29
  30typedef int (kiocb_cancel_fn)(struct kiocb *, struct io_event *);
  31
  32struct kiocb {
  33        atomic_t                ki_users;
  34
  35        struct file             *ki_filp;
  36        struct kioctx           *ki_ctx;        /* NULL for sync ops */
  37        kiocb_cancel_fn         *ki_cancel;
  38        void                    (*ki_dtor)(struct kiocb *);
  39
  40        union {
  41                void __user             *user;
  42                struct task_struct      *tsk;
  43        } ki_obj;
  44
  45        __u64                   ki_user_data;   /* user's data for completion */
  46        loff_t                  ki_pos;
  47
  48        void                    *private;
  49        /* State that we remember to be able to restart/retry  */
  50        unsigned short          ki_opcode;
  51        size_t                  ki_nbytes;      /* copy of iocb->aio_nbytes */
  52        char                    __user *ki_buf; /* remaining iocb->aio_buf */
  53        size_t                  ki_left;        /* remaining bytes */
  54        struct iovec            ki_inline_vec;  /* inline vector */
  55        struct iovec            *ki_iovec;
  56        unsigned long           ki_nr_segs;
  57        unsigned long           ki_cur_seg;
  58
  59        struct list_head        ki_list;        /* the aio core uses this
  60                                                 * for cancellation */
  61
  62        /*
  63         * If the aio_resfd field of the userspace iocb is not zero,
  64         * this is the underlying eventfd context to deliver events to.
  65         */
  66        struct eventfd_ctx      *ki_eventfd;
  67};
  68
  69static inline bool is_sync_kiocb(struct kiocb *kiocb)
  70{
  71        return kiocb->ki_ctx == NULL;
  72}
  73
  74static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
  75{
  76        *kiocb = (struct kiocb) {
  77                        .ki_users = ATOMIC_INIT(1),
  78                        .ki_ctx = NULL,
  79                        .ki_filp = filp,
  80                        .ki_obj.tsk = current,
  81                };
  82}
  83
  84/* prototypes */
  85#ifdef CONFIG_AIO
  86extern ssize_t wait_on_sync_kiocb(struct kiocb *iocb);
  87extern void aio_put_req(struct kiocb *iocb);
  88extern void aio_complete(struct kiocb *iocb, long res, long res2);
  89struct mm_struct;
  90extern void exit_aio(struct mm_struct *mm);
  91extern long do_io_submit(aio_context_t ctx_id, long nr,
  92                         struct iocb __user *__user *iocbpp, bool compat);
  93void kiocb_set_cancel_fn(struct kiocb *req, kiocb_cancel_fn *cancel);
  94#else
  95static inline ssize_t wait_on_sync_kiocb(struct kiocb *iocb) { return 0; }
  96static inline void aio_put_req(struct kiocb *iocb) { }
  97static inline void aio_complete(struct kiocb *iocb, long res, long res2) { }
  98struct mm_struct;
  99static inline void exit_aio(struct mm_struct *mm) { }
 100static inline long do_io_submit(aio_context_t ctx_id, long nr,
 101                                struct iocb __user * __user *iocbpp,
 102                                bool compat) { return 0; }
 103static inline void kiocb_set_cancel_fn(struct kiocb *req,
 104                                       kiocb_cancel_fn *cancel) { }
 105#endif /* CONFIG_AIO */
 106
 107static inline struct kiocb *list_kiocb(struct list_head *h)
 108{
 109        return list_entry(h, struct kiocb, ki_list);
 110}
 111
 112/* for sysctl: */
 113extern unsigned long aio_nr;
 114extern unsigned long aio_max_nr;
 115
 116#endif /* __LINUX__AIO_H */
 117