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 /* ki_flags bits */
  27 #define KIF_LOCKED              0
  28 #define KIF_KICKED              1
  29 #define KIF_CANCELLED           2
  30
  31 #define kiocbTryLock(iocb)      test_and_set_bit(KIF_LOCKED, &(iocb)->ki_flags)
  32 #define kiocbTryKick(iocb)      test_and_set_bit(KIF_KICKED, &(iocb)->ki_flags)
  33
  34 #define kiocbSetLocked(iocb)    set_bit(KIF_LOCKED, &(iocb)->ki_flags)
  35 #define kiocbSetKicked(iocb)    set_bit(KIF_KICKED, &(iocb)->ki_flags)
  36 #define kiocbSetCancelled(iocb) set_bit(KIF_CANCELLED, &(iocb)->ki_flags)
  37
  38 #define kiocbClearLocked(iocb)  clear_bit(KIF_LOCKED, &(iocb)->ki_flags)
  39 #define kiocbClearKicked(iocb)  clear_bit(KIF_KICKED, &(iocb)->ki_flags)
  40 #define kiocbClearCancelled(iocb)       clear_bit(KIF_CANCELLED, &(iocb)->ki_flags)
  41
  42 #define kiocbIsLocked(iocb)     test_bit(KIF_LOCKED, &(iocb)->ki_flags)
  43 #define kiocbIsKicked(iocb)     test_bit(KIF_KICKED, &(iocb)->ki_flags)
  44 #define kiocbIsCancelled(iocb)  test_bit(KIF_CANCELLED, &(iocb)->ki_flags)
  45
  46 struct kiocb {
  47         struct list_head        ki_run_list;
  48         long                    ki_flags;
  49         int                     ki_users;
  50         unsigned                ki_key;         /* id of this request */
  51
  52         struct file             *ki_filp;
  53         struct kioctx           *ki_ctx;        /* may be NULL for sync ops */
  54         int                     (*ki_cancel)(struct kiocb *, struct io_event *);
  55         ssize_t                 (*ki_retry)(struct kiocb *);
  56         void                    (*ki_dtor)(struct kiocb *);
  57
  58         struct list_head        ki_list;        /* the aio core uses this
  59                                                  * for cancellation */
  60
  61         union {
  62                 void __user             *user;
  63                 struct task_struct      *tsk;
  64         } ki_obj;
  65         __u64                   ki_user_data;   /* user's data for completion */
  66         loff_t                  ki_pos;
  67         /* State that we remember to be able to restart/retry  */
  68         unsigned short          ki_opcode;
  69         size_t                  ki_nbytes;      /* copy of iocb->aio_nbytes */
  70         char                    __user *ki_buf; /* remaining iocb->aio_buf */
  71         size_t                  ki_left;        /* remaining bytes */
  72         wait_queue_t            ki_wait;
  73         long                    ki_retried;     /* just for testing */
  74         long                    ki_kicked;      /* just for testing */
  75         long                    ki_queued;      /* just for testing */
  76
  77         void                    *private;
  78 };
  79
  80 #define is_sync_kiocb(iocb)     ((iocb)->ki_key == KIOCB_SYNC_KEY)
  81 #define init_sync_kiocb(x, filp)                        \
  82         do {                                            \
  83                 struct task_struct *tsk = current;      \
  84                 (x)->ki_flags = 0;                      \
  85                 (x)->ki_users = 1;                      \
  86                 (x)->ki_key = KIOCB_SYNC_KEY;           \
  87                 (x)->ki_filp = (filp);                  \
  88                 (x)->ki_ctx = &tsk->active_mm->default_kioctx;  \
  89                 (x)->ki_cancel = NULL;                  \
  90                 (x)->ki_dtor = NULL;                    \
  91                 (x)->ki_obj.tsk = tsk;                  \
  92                 (x)->ki_user_data = 0;                  \
  93                 init_wait((&(x)->ki_wait));             \
  94         } while (0)
  95
  96 #define AIO_RING_MAGIC                  0xa10a10a1
  97 #define AIO_RING_COMPAT_FEATURES        1
  98 #define AIO_RING_INCOMPAT_FEATURES      0
  99 struct aio_ring {
 100         unsigned        id;     /* kernel internal index number */
 101         unsigned        nr;     /* number of io_events */
 102         unsigned        head;
 103         unsigned        tail;
 104
 105         unsigned        magic;
 106         unsigned        compat_features;
 107         unsigned        incompat_features;
 108         unsigned        header_length;  /* size of aio_ring */
 109
 110
 111         struct io_event         io_events[0];
 112 }; /* 128 bytes + ring size */
 113
 114 #define aio_ring_avail(info, ring)      (((ring)->head + (info)->nr - 1 - (ring)->tail) % (info)->nr)
 115
 116 #define AIO_RING_PAGES  8
 117 struct aio_ring_info {
 118         unsigned long           mmap_base;
 119         unsigned long           mmap_size;
 120
 121         struct page             **ring_pages;
 122         spinlock_t              ring_lock;
 123         long                    nr_pages;
 124
 125         unsigned                nr, tail;
 126
 127         struct page             *internal_pages[AIO_RING_PAGES];
 128 };
 129
 130 struct kioctx {
 131         atomic_t                users;
 132         int                     dead;
 133         struct mm_struct        *mm;
 134
 135         /* This needs improving */
 136         unsigned long           user_id;
 137         struct kioctx           *next;
 138
 139         wait_queue_head_t       wait;
 140
 141         spinlock_t              ctx_lock;
 142
 143         int                     reqs_active;
 144         struct list_head        active_reqs;    /* used for cancellation */
 145         struct list_head        run_list;       /* used for kicked reqs */
 146
 147         unsigned                max_reqs;
 148
 149         struct aio_ring_info    ring_info;
 150
 151         struct work_struct      wq;
 152 };
 153
 154 /* prototypes */
 155 extern unsigned aio_max_size;
 156
 157 extern ssize_t FASTCALL(wait_on_sync_kiocb(struct kiocb *iocb));
 158 extern int FASTCALL(aio_put_req(struct kiocb *iocb));
 159 extern void FASTCALL(kick_iocb(struct kiocb *iocb));
 160 extern int FASTCALL(aio_complete(struct kiocb *iocb, long res, long res2));
 161 extern void FASTCALL(__put_ioctx(struct kioctx *ctx));
 162 struct mm_struct;
 163 extern void FASTCALL(exit_aio(struct mm_struct *mm));
 164 extern struct kioctx *lookup_ioctx(unsigned long ctx_id);
 165 extern int FASTCALL(io_submit_one(struct kioctx *ctx,
 166                         struct iocb __user *user_iocb, struct iocb *iocb));
 167
 168 /* semi private, but used by the 32bit emulations: */
 169 struct kioctx *lookup_ioctx(unsigned long ctx_id);
 170 int FASTCALL(io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
 171                                   struct iocb *iocb));
 172
 173 #define get_ioctx(kioctx)       do { if (unlikely(atomic_read(&(kioctx)->users) <= 0)) BUG(); atomic_inc(&(kioctx)->users); } while (0)
 174 #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)
 175
 176 #define in_aio() !is_sync_wait(current->io_wait)
 177 /* may be used for debugging */
 178 #define warn_if_async()                                                 \
 179 do {                                                                    \
 180         if (in_aio()) {                                                 \
 181                 printk(KERN_ERR "%s(%s:%d) called in async context!\n", \
 182                         __FUNCTION__, __FILE__, __LINE__);              \
 183                 dump_stack();                                           \
 184         }                                                               \
 185 } while (0)
 186
 187 #define io_wait_to_kiocb(wait) container_of(wait, struct kiocb, ki_wait)
 188 #define is_retried_kiocb(iocb) ((iocb)->ki_retried > 1)
 189
 190 #include <linux/aio_abi.h>
 191
 192 static inline struct kiocb *list_kiocb(struct list_head *h)
 193 {
 194         return list_entry(h, struct kiocb, ki_list);
 195 }
 196
 197 /* for sysctl: */
 198 extern atomic_t aio_nr;
 199 extern unsigned aio_max_nr;
 200
 201 #endif /* __LINUX__AIO_H */