#define KIOCB_SYNC_KEY (~0U)
/* ki_flags bits */
-#define KIF_LOCKED 0
+/*
+ * This may be used for cancel/retry serialization in the future, but
+ * for now it's unused and we probably don't want modules to even
+ * think they can use it.
+ */
+/* #define KIF_LOCKED 0 */
#define KIF_KICKED 1
#define KIF_CANCELLED 2
#define kiocbIsKicked(iocb) test_bit(KIF_KICKED, &(iocb)->ki_flags)
#define kiocbIsCancelled(iocb) test_bit(KIF_CANCELLED, &(iocb)->ki_flags)
+/* is there a better place to document function pointer methods? */
+/**
+ * ki_retry - iocb forward progress callback
+ * @kiocb: The kiocb struct to advance by performing an operation.
+ *
+ * This callback is called when the AIO core wants a given AIO operation
+ * to make forward progress. The kiocb argument describes the operation
+ * that is to be performed. As the operation proceeds, perhaps partially,
+ * ki_retry is expected to update the kiocb with progress made. Typically
+ * ki_retry is set in the AIO core and it itself calls file_operations
+ * helpers.
+ *
+ * ki_retry's return value determines when the AIO operation is completed
+ * and an event is generated in the AIO event ring. Except the special
+ * return values described below, the value that is returned from ki_retry
+ * is transferred directly into the completion ring as the operation's
+ * resulting status. Once this has happened ki_retry *MUST NOT* reference
+ * the kiocb pointer again.
+ *
+ * If ki_retry returns -EIOCBQUEUED it has made a promise that aio_complete()
+ * will be called on the kiocb pointer in the future. The AIO core will
+ * not ask the method again -- ki_retry must ensure forward progress.
+ * aio_complete() must be called once and only once in the future, multiple
+ * calls may result in undefined behaviour.
+ *
+ * If ki_retry returns -EIOCBRETRY it has made a promise that kick_iocb()
+ * will be called on the kiocb pointer in the future. This may happen
+ * through generic helpers that associate kiocb->ki_wait with a wait
+ * queue head that ki_retry uses via current->io_wait. It can also happen
+ * with custom tracking and manual calls to kick_iocb(), though that is
+ * discouraged. In either case, kick_iocb() must be called once and only
+ * once. ki_retry must ensure forward progress, the AIO core will wait
+ * indefinitely for kick_iocb() to be called.
+ */
struct kiocb {
struct list_head ki_run_list;
long ki_flags;
ssize_t (*ki_retry)(struct kiocb *);
void (*ki_dtor)(struct kiocb *);
- struct list_head ki_list; /* the aio core uses this
- * for cancellation */
-
union {
void __user *user;
struct task_struct *tsk;
} ki_obj;
+
__u64 ki_user_data; /* user's data for completion */
+ wait_queue_t ki_wait;
loff_t ki_pos;
+
+ void *private;
/* State that we remember to be able to restart/retry */
unsigned short ki_opcode;
size_t ki_nbytes; /* copy of iocb->aio_nbytes */
char __user *ki_buf; /* remaining iocb->aio_buf */
size_t ki_left; /* remaining bytes */
- wait_queue_t ki_wait;
long ki_retried; /* just for testing */
long ki_kicked; /* just for testing */
long ki_queued; /* just for testing */
- void *private;
+ struct list_head ki_list; /* the aio core uses this
+ * for cancellation */
};
#define is_sync_kiocb(iocb) ((iocb)->ki_key == KIOCB_SYNC_KEY)
(x)->ki_users = 1; \
(x)->ki_key = KIOCB_SYNC_KEY; \
(x)->ki_filp = (filp); \
- (x)->ki_ctx = &tsk->active_mm->default_kioctx; \
+ (x)->ki_ctx = NULL; \
(x)->ki_cancel = NULL; \
+ (x)->ki_retry = NULL; \
(x)->ki_dtor = NULL; \
(x)->ki_obj.tsk = tsk; \
(x)->ki_user_data = 0; \
struct list_head active_reqs; /* used for cancellation */
struct list_head run_list; /* used for kicked reqs */
+ /* sys_io_setup currently limits this to an unsigned int */
unsigned max_reqs;
struct aio_ring_info ring_info;
int FASTCALL(io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
struct iocb *iocb));
-#define get_ioctx(kioctx) do { if (unlikely(atomic_read(&(kioctx)->users) <= 0)) BUG(); atomic_inc(&(kioctx)->users); } while (0)
-#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)
+#define get_ioctx(kioctx) do { \
+ BUG_ON(unlikely(atomic_read(&(kioctx)->users) <= 0)); \
+ atomic_inc(&(kioctx)->users); \
+} while (0)
+#define put_ioctx(kioctx) do { \
+ BUG_ON(unlikely(atomic_read(&(kioctx)->users) <= 0)); \
+ if (unlikely(atomic_dec_and_test(&(kioctx)->users))) \
+ __put_ioctx(kioctx); \
+} while (0)
#define in_aio() !is_sync_wait(current->io_wait)
/* may be used for debugging */
}
/* for sysctl: */
-extern atomic_t aio_nr;
-extern unsigned aio_max_nr;
+extern unsigned long aio_nr;
+extern unsigned long aio_max_nr;
#endif /* __LINUX__AIO_H */
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