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
   8 #include <asm/atomic.h>
   9
  10 #define AIO_MAXSEGS             4
  11 #define AIO_KIOGRP_NR_ATOMIC    8
  12
  13 struct kioctx;
  14
  15 /* Notes on cancelling a kiocb:
  16  *      If a kiocb is cancelled, aio_complete may return 0 to indicate
  17  *      that cancel has not yet disposed of the kiocb.  All cancel
  18  *      operations *must* call aio_put_req to dispose of the kiocb
  19  *      to guard against races with the completion code.
  20  */
  21 #define KIOCB_C_CANCELLED       0x01
  22 #define KIOCB_C_COMPLETE        0x02
  23
  24 #define KIOCB_SYNC_KEY          (~0U)
  25
  26 #define KIOCB_PRIVATE_SIZE      (24 * sizeof(long))
  27
  28 /* ki_flags bits */
  29 #define KIF_LOCKED              0
  30 #define KIF_KICKED              1
  31 #define KIF_CANCELLED           2
  32
  33 #define kiocbTryLock(iocb)      test_and_set_bit(KIF_LOCKED, &(iocb)->ki_flags)
  34 #define kiocbTryKick(iocb)      test_and_set_bit(KIF_KICKED, &(iocb)->ki_flags)
  35
  36 #define kiocbSetLocked(iocb)    set_bit(KIF_LOCKED, &(iocb)->ki_flags)
  37 #define kiocbSetKicked(iocb)    set_bit(KIF_KICKED, &(iocb)->ki_flags)
  38 #define kiocbSetCancelled(iocb) set_bit(KIF_CANCELLED, &(iocb)->ki_flags)
  39
  40 #define kiocbClearLocked(iocb)  clear_bit(KIF_LOCKED, &(iocb)->ki_flags)
  41 #define kiocbClearKicked(iocb)  clear_bit(KIF_KICKED, &(iocb)->ki_flags)
  42 #define kiocbClearCancelled(iocb)       clear_bit(KIF_CANCELLED, &(iocb)->ki_flags)
  43
  44 #define kiocbIsLocked(iocb)     test_bit(KIF_LOCKED, &(iocb)->ki_flags)
  45 #define kiocbIsKicked(iocb)     test_bit(KIF_KICKED, &(iocb)->ki_flags)
  46 #define kiocbIsCancelled(iocb)  test_bit(KIF_CANCELLED, &(iocb)->ki_flags)
  47
  48 struct kiocb {
  49         struct list_head        ki_run_list;
  50         long                    ki_flags;
  51         int                     ki_users;
  52         unsigned                ki_key;         /* id of this request */
  53
  54         struct file             *ki_filp;
  55         struct kioctx           *ki_ctx;        /* may be NULL for sync ops */
  56         int                     (*ki_cancel)(struct kiocb *, struct io_event *);
  57         ssize_t                 (*ki_retry)(struct kiocb *);
  58
  59         struct list_head        ki_list;        /* the aio core uses this
  60                                                  * for cancellation */
  61
  62         void                    *ki_user_obj;   /* pointer to userland's iocb */
  63         __u64                   ki_user_data;   /* user's data for completion */
  64         loff_t                  ki_pos;
  65
  66         /* State that we remember to be able to restart/retry  */
  67         unsigned short          ki_opcode;
  68         size_t                  ki_nbytes;      /* copy of iocb->aio_nbytes */
  69         char                    *ki_buf;        /* remaining iocb->aio_buf */
  70         size_t                  ki_left;        /* remaining bytes */
  71         wait_queue_t            ki_wait;
  72         long                    ki_retried;     /* just for testing */
  73         long                    ki_kicked;      /* just for testing */
  74         long                    ki_queued;      /* just for testing */
  75
  76         char                    private[KIOCB_PRIVATE_SIZE];
  77 };
  78
  79 #define is_sync_kiocb(iocb)     ((iocb)->ki_key == KIOCB_SYNC_KEY)
  80 #define init_sync_kiocb(x, filp)                        \
  81         do {                                            \
  82                 struct task_struct *tsk = current;      \
  83                 (x)->ki_flags = 0;                      \
  84                 (x)->ki_users = 1;                      \
  85                 (x)->ki_key = KIOCB_SYNC_KEY;           \
  86                 (x)->ki_filp = (filp);                  \
  87                 (x)->ki_ctx = &tsk->active_mm->default_kioctx;  \
  88                 (x)->ki_cancel = NULL;                  \
  89                 (x)->ki_user_obj = tsk;                 \
  90                 (x)->ki_user_data = 0;                  \
  91                 init_wait((&(x)->ki_wait));             \
  92         } while (0)
  93
  94 #define AIO_RING_MAGIC                  0xa10a10a1
  95 #define AIO_RING_COMPAT_FEATURES        1
  96 #define AIO_RING_INCOMPAT_FEATURES      0
  97 struct aio_ring {
  98         unsigned        id;     /* kernel internal index number */
  99         unsigned        nr;     /* number of io_events */
 100         unsigned        head;
 101         unsigned        tail;
 102
 103         unsigned        magic;
 104         unsigned        compat_features;
 105         unsigned        incompat_features;
 106         unsigned        header_length;  /* size of aio_ring */
 107
 108
 109         struct io_event         io_events[0];
 110 }; /* 128 bytes + ring size */
 111
 112 #define aio_ring_avail(info, ring)      (((ring)->head + (info)->nr - 1 - (ring)->tail) % (info)->nr)
 113
 114 #define AIO_RING_PAGES  8
 115 struct aio_ring_info {
 116         unsigned long           mmap_base;
 117         unsigned long           mmap_size;
 118
 119         struct page             **ring_pages;
 120         spinlock_t              ring_lock;
 121         long                    nr_pages;
 122
 123         unsigned                nr, tail;
 124
 125         struct page             *internal_pages[AIO_RING_PAGES];
 126 };
 127
 128 struct kioctx {
 129         atomic_t                users;
 130         int                     dead;
 131         struct mm_struct        *mm;
 132
 133         /* This needs improving */
 134         unsigned long           user_id;
 135         struct kioctx           *next;
 136
 137         wait_queue_head_t       wait;
 138
 139         spinlock_t              ctx_lock;
 140
 141         int                     reqs_active;
 142         struct list_head        active_reqs;    /* used for cancellation */
 143         struct list_head        run_list;       /* used for kicked reqs */
 144
 145         unsigned                max_reqs;
 146
 147         struct aio_ring_info    ring_info;
 148
 149         struct work_struct      wq;
 150 };
 151
 152 /* prototypes */
 153 extern unsigned aio_max_size;
 154
 155 extern ssize_t FASTCALL(wait_on_sync_kiocb(struct kiocb *iocb));
 156 extern int FASTCALL(aio_put_req(struct kiocb *iocb));
 157 extern void FASTCALL(kick_iocb(struct kiocb *iocb));
 158 extern int FASTCALL(aio_complete(struct kiocb *iocb, long res, long res2));
 159 extern void FASTCALL(__put_ioctx(struct kioctx *ctx));
 160 struct mm_struct;
 161 extern void FASTCALL(exit_aio(struct mm_struct *mm));
 162 extern struct kioctx *lookup_ioctx(unsigned long ctx_id);
 163 extern int FASTCALL(io_submit_one(struct kioctx *ctx,
 164                         struct iocb *user_iocb, struct iocb *iocb));
 165
 166 /* semi private, but used by the 32bit emulations: */
 167 struct kioctx *lookup_ioctx(unsigned long ctx_id);
 168 int FASTCALL(io_submit_one(struct kioctx *ctx, struct iocb *user_iocb,
 169                                   struct iocb *iocb));
 170
 171 #define get_ioctx(kioctx)       do { if (unlikely(atomic_read(&(kioctx)->users) <= 0)) BUG(); atomic_inc(&(kioctx)->users); } while (0)
 172 #define put_ioctx(kioctx)       do { if (unlikely(atomic_dec_and_test(&(kioctx)->users))) __put_ioctx(kioctx); else if (unlikely(atomic_read(&(kioctx)->users) < 0)) BUG(); } while (0)
 173
 174 #define in_aio() !is_sync_wait(current->io_wait)
 175 /* may be used for debugging */
 176 #define warn_if_async() if (in_aio()) {\
 177         printk(KERN_ERR "%s(%s:%d) called in async context!\n", \
 178         __FUNCTION__, __FILE__, __LINE__); \
 179         dump_stack(); \
 180         }
 181
 182 #define io_wait_to_kiocb(wait) container_of(wait, struct kiocb, ki_wait)
 183 #define is_retried_kiocb(iocb) ((iocb)->ki_retried > 1)
 184
 185 #include <linux/aio_abi.h>
 186
 187 static inline struct kiocb *list_kiocb(struct list_head *h)
 188 {
 189         return list_entry(h, struct kiocb, ki_list);
 190 }
 191
 192 /* for sysctl: */
 193 extern unsigned aio_max_nr, aio_max_size, aio_max_pinned;
 194
 195 #endif /* __LINUX__AIO_H */