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 *);
  31
  32struct kiocb {
  33        struct file             *ki_filp;
  34        struct kioctx           *ki_ctx;        /* NULL for sync ops */
  35        kiocb_cancel_fn         *ki_cancel;
  36        void                    *private;
  37
  38        union {
  39                void __user             *user;
  40                struct task_struct      *tsk;
  41        } ki_obj;
  42
  43        __u64                   ki_user_data;   /* user's data for completion */
  44        loff_t                  ki_pos;
  45        size_t                  ki_nbytes;      /* copy of iocb->aio_nbytes */
  46
  47        struct list_head        ki_list;        /* the aio core uses this
  48                                                 * for cancellation */
  49
  50        /*
  51         * If the aio_resfd field of the userspace iocb is not zero,
  52         * this is the underlying eventfd context to deliver events to.
  53         */
  54        struct eventfd_ctx      *ki_eventfd;
  55};
  56
  57static inline bool is_sync_kiocb(struct kiocb *kiocb)
  58{
  59        return kiocb->ki_ctx == NULL;
  60}
  61
  62static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
  63{
  64        *kiocb = (struct kiocb) {
  65                        .ki_ctx = NULL,
  66                        .ki_filp = filp,
  67                        .ki_obj.tsk = current,
  68                };
  69}
  70
  71/* prototypes */
  72#ifdef CONFIG_AIO
  73extern ssize_t wait_on_sync_kiocb(struct kiocb *iocb);
  74extern void aio_complete(struct kiocb *iocb, long res, long res2);
  75struct mm_struct;
  76extern void exit_aio(struct mm_struct *mm);
  77extern long do_io_submit(aio_context_t ctx_id, long nr,
  78                         struct iocb __user *__user *iocbpp, bool compat);
  79void kiocb_set_cancel_fn(struct kiocb *req, kiocb_cancel_fn *cancel);
  80#else
  81static inline ssize_t wait_on_sync_kiocb(struct kiocb *iocb) { return 0; }
  82static inline void aio_complete(struct kiocb *iocb, long res, long res2) { }
  83struct mm_struct;
  84static inline void exit_aio(struct mm_struct *mm) { }
  85static inline long do_io_submit(aio_context_t ctx_id, long nr,
  86                                struct iocb __user * __user *iocbpp,
  87                                bool compat) { return 0; }
  88static inline void kiocb_set_cancel_fn(struct kiocb *req,
  89                                       kiocb_cancel_fn *cancel) { }
  90#endif /* CONFIG_AIO */
  91
  92static inline struct kiocb *list_kiocb(struct list_head *h)
  93{
  94        return list_entry(h, struct kiocb, ki_list);
  95}
  96
  97/* for sysctl: */
  98extern unsigned long aio_nr;
  99extern unsigned long aio_max_nr;
 100
 101#endif /* __LINUX__AIO_H */
 102