LXR linux-bk/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
  13struct 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
  46struct 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
  99struct 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
 117struct 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
 130struct 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 */
 155extern unsigned aio_max_size;
 156
 157extern ssize_t FASTCALL(wait_on_sync_kiocb(struct kiocb *iocb));
 158extern int FASTCALL(aio_put_req(struct kiocb *iocb));
 159extern void FASTCALL(kick_iocb(struct kiocb *iocb));
 160extern int FASTCALL(aio_complete(struct kiocb *iocb, long res, long res2));
 161extern void FASTCALL(__put_ioctx(struct kioctx *ctx));
 162struct mm_struct;
 163extern void FASTCALL(exit_aio(struct mm_struct *mm));
 164extern struct kioctx *lookup_ioctx(unsigned long ctx_id);
 165extern 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: */
 169struct kioctx *lookup_ioctx(unsigned long ctx_id);
 170int 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()                                                 \
 179do {                                                                    \
 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
 192static inline struct kiocb *list_kiocb(struct list_head *h)
 193{
 194        return list_entry(h, struct kiocb, ki_list);
 195}
 196
 197/* for sysctl: */
 198extern atomic_t aio_nr;
 199extern unsigned aio_max_nr;
 200
 201#endif /* __LINUX__AIO_H */
 202