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
  12 struct kioctx;
  13 struct 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
  30 typedef int (kiocb_cancel_fn)(struct kiocb *, struct io_event *);
  31
  32 struct 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
  69 static inline bool is_sync_kiocb(struct kiocb *kiocb)
  70 {
  71         return kiocb->ki_ctx == NULL;
  72 }
  73
  74 static 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
  86 extern ssize_t wait_on_sync_kiocb(struct kiocb *iocb);
  87 extern void aio_put_req(struct kiocb *iocb);
  88 extern void aio_complete(struct kiocb *iocb, long res, long res2);
  89 struct mm_struct;
  90 extern void exit_aio(struct mm_struct *mm);
  91 extern long do_io_submit(aio_context_t ctx_id, long nr,
  92                          struct iocb __user *__user *iocbpp, bool compat);
  93 void kiocb_set_cancel_fn(struct kiocb *req, kiocb_cancel_fn *cancel);
  94 #else
  95 static inline ssize_t wait_on_sync_kiocb(struct kiocb *iocb) { return 0; }
  96 static inline void aio_put_req(struct kiocb *iocb) { }
  97 static inline void aio_complete(struct kiocb *iocb, long res, long res2) { }
  98 struct mm_struct;
  99 static inline void exit_aio(struct mm_struct *mm) { }
 100 static inline long do_io_submit(aio_context_t ctx_id, long nr,
 101                                 struct iocb __user * __user *iocbpp,
 102                                 bool compat) { return 0; }
 103 static inline void kiocb_set_cancel_fn(struct kiocb *req,
 104                                        kiocb_cancel_fn *cancel) { }
 105 #endif /* CONFIG_AIO */
 106
 107 static inline struct kiocb *list_kiocb(struct list_head *h)
 108 {
 109         return list_entry(h, struct kiocb, ki_list);
 110 }
 111
 112 /* for sysctl: */
 113 extern unsigned long aio_nr;
 114 extern unsigned long aio_max_nr;
 115
 116 #endif /* __LINUX__AIO_H */