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         long                    (*ki_retry)(struct kiocb *);
  58
  59         struct list_head        ki_list;        /* the aio core uses this
  60                                                  * for cancellation */
  61
  62         void __user             *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         char                    private[KIOCB_PRIVATE_SIZE];
  67 };
  68
  69 #define is_sync_kiocb(iocb)     ((iocb)->ki_key == KIOCB_SYNC_KEY)
  70 #define init_sync_kiocb(x, filp)                        \
  71         do {                                            \
  72                 struct task_struct *tsk = current;      \
  73                 (x)->ki_flags = 0;                      \
  74                 (x)->ki_users = 1;                      \
  75                 (x)->ki_key = KIOCB_SYNC_KEY;           \
  76                 (x)->ki_filp = (filp);                  \
  77                 (x)->ki_ctx = &tsk->active_mm->default_kioctx;  \
  78                 (x)->ki_cancel = NULL;                  \
  79                 (x)->ki_user_obj = tsk;                 \
  80         } while (0)
  81
  82 #define AIO_RING_MAGIC                  0xa10a10a1
  83 #define AIO_RING_COMPAT_FEATURES        1
  84 #define AIO_RING_INCOMPAT_FEATURES      0
  85 struct aio_ring {
  86         unsigned        id;     /* kernel internal index number */
  87         unsigned        nr;     /* number of io_events */
  88         unsigned        head;
  89         unsigned        tail;
  90
  91         unsigned        magic;
  92         unsigned        compat_features;
  93         unsigned        incompat_features;
  94         unsigned        header_length;  /* size of aio_ring */
  95
  96
  97         struct io_event         io_events[0];
  98 }; /* 128 bytes + ring size */
  99
 100 #define aio_ring_avail(info, ring)      (((ring)->head + (info)->nr - 1 - (ring)->tail) % (info)->nr)
 101
 102 #define AIO_RING_PAGES  8
 103 struct aio_ring_info {
 104         unsigned long           mmap_base;
 105         unsigned long           mmap_size;
 106
 107         struct page             **ring_pages;
 108         spinlock_t              ring_lock;
 109         long                    nr_pages;
 110
 111         unsigned                nr, tail;
 112
 113         struct page             *internal_pages[AIO_RING_PAGES];
 114 };
 115
 116 struct kioctx {
 117         atomic_t                users;
 118         int                     dead;
 119         struct mm_struct        *mm;
 120
 121         /* This needs improving */
 122         unsigned long           user_id;
 123         struct kioctx           *next;
 124
 125         wait_queue_head_t       wait;
 126
 127         spinlock_t              ctx_lock;
 128
 129         int                     reqs_active;
 130         struct list_head        active_reqs;    /* used for cancellation */
 131         struct list_head        run_list;       /* used for kicked reqs */
 132
 133         unsigned                max_reqs;
 134
 135         struct aio_ring_info    ring_info;
 136
 137         struct work_struct      wq;
 138 };
 139
 140 /* prototypes */
 141 extern unsigned aio_max_size;
 142
 143 extern ssize_t FASTCALL(wait_on_sync_kiocb(struct kiocb *iocb));
 144 extern int FASTCALL(aio_put_req(struct kiocb *iocb));
 145 extern void FASTCALL(kick_iocb(struct kiocb *iocb));
 146 extern int FASTCALL(aio_complete(struct kiocb *iocb, long res, long res2));
 147 extern void FASTCALL(__put_ioctx(struct kioctx *ctx));
 148 struct mm_struct;
 149 extern void FASTCALL(exit_aio(struct mm_struct *mm));
 150 extern struct kioctx *lookup_ioctx(unsigned long ctx_id);
 151 extern int FASTCALL(io_submit_one(struct kioctx *ctx,
 152                         struct iocb *user_iocb, struct iocb *iocb));
 153
 154 /* semi private, but used by the 32bit emulations: */
 155 struct kioctx *lookup_ioctx(unsigned long ctx_id);
 156 int FASTCALL(io_submit_one(struct kioctx *ctx, struct iocb *user_iocb,
 157                                   struct iocb *iocb));
 158
 159 #define get_ioctx(kioctx)       do { if (unlikely(atomic_read(&(kioctx)->users) <= 0)) BUG(); atomic_inc(&(kioctx)->users); } while (0)
 160 #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)
 161
 162 #include <linux/aio_abi.h>
 163
 164 static inline struct kiocb *list_kiocb(struct list_head *h)
 165 {
 166         return list_entry(h, struct kiocb, ki_list);
 167 }
 168
 169 /* for sysctl: */
 170 extern atomic_t aio_nr;
 171 extern unsigned aio_max_nr;
 172
 173 #endif /* __LINUX__AIO_H */