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-rw-r--r--include/linux/aio.h178
1 files changed, 26 insertions, 152 deletions
diff --git a/include/linux/aio.h b/include/linux/aio.h
index 31ff6dba4872..1bdf965339f9 100644
--- a/include/linux/aio.h
+++ b/include/linux/aio.h
@@ -9,91 +9,32 @@
#include <linux/atomic.h>
-#define AIO_MAXSEGS 4
-#define AIO_KIOGRP_NR_ATOMIC 8
-
struct kioctx;
+struct kiocb;
-/* Notes on cancelling a kiocb:
- * If a kiocb is cancelled, aio_complete may return 0 to indicate
- * that cancel has not yet disposed of the kiocb. All cancel
- * operations *must* call aio_put_req to dispose of the kiocb
- * to guard against races with the completion code.
- */
-#define KIOCB_C_CANCELLED 0x01
-#define KIOCB_C_COMPLETE 0x02
-
-#define KIOCB_SYNC_KEY (~0U)
+#define KIOCB_KEY 0
-/* ki_flags bits */
/*
- * 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.
+ * We use ki_cancel == KIOCB_CANCELLED to indicate that a kiocb has been either
+ * cancelled or completed (this makes a certain amount of sense because
+ * successful cancellation - io_cancel() - does deliver the completion to
+ * userspace).
+ *
+ * And since most things don't implement kiocb cancellation and we'd really like
+ * kiocb completion to be lockless when possible, we use ki_cancel to
+ * synchronize cancellation and completion - we only set it to KIOCB_CANCELLED
+ * with xchg() or cmpxchg(), see batch_complete_aio() and kiocb_cancel().
*/
-/* #define KIF_LOCKED 0 */
-#define KIF_KICKED 1
-#define KIF_CANCELLED 2
-
-#define kiocbTryLock(iocb) test_and_set_bit(KIF_LOCKED, &(iocb)->ki_flags)
-#define kiocbTryKick(iocb) test_and_set_bit(KIF_KICKED, &(iocb)->ki_flags)
+#define KIOCB_CANCELLED ((void *) (~0ULL))
-#define kiocbSetLocked(iocb) set_bit(KIF_LOCKED, &(iocb)->ki_flags)
-#define kiocbSetKicked(iocb) set_bit(KIF_KICKED, &(iocb)->ki_flags)
-#define kiocbSetCancelled(iocb) set_bit(KIF_CANCELLED, &(iocb)->ki_flags)
+typedef int (kiocb_cancel_fn)(struct kiocb *, struct io_event *);
-#define kiocbClearLocked(iocb) clear_bit(KIF_LOCKED, &(iocb)->ki_flags)
-#define kiocbClearKicked(iocb) clear_bit(KIF_KICKED, &(iocb)->ki_flags)
-#define kiocbClearCancelled(iocb) clear_bit(KIF_CANCELLED, &(iocb)->ki_flags)
-
-#define kiocbIsLocked(iocb) test_bit(KIF_LOCKED, &(iocb)->ki_flags)
-#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;
- unsigned long ki_flags;
- int ki_users;
- unsigned ki_key; /* id of this request */
+ atomic_t ki_users;
struct file *ki_filp;
- struct kioctx *ki_ctx; /* may be NULL for sync ops */
- int (*ki_cancel)(struct kiocb *, struct io_event *);
- ssize_t (*ki_retry)(struct kiocb *);
+ struct kioctx *ki_ctx; /* NULL for sync ops */
+ kiocb_cancel_fn *ki_cancel;
void (*ki_dtor)(struct kiocb *);
union {
@@ -117,7 +58,6 @@ struct kiocb {
struct list_head ki_list; /* the aio core uses this
* for cancellation */
- struct list_head ki_batch; /* batch allocation */
/*
* If the aio_resfd field of the userspace iocb is not zero,
@@ -128,106 +68,40 @@ struct kiocb {
static inline bool is_sync_kiocb(struct kiocb *kiocb)
{
- return kiocb->ki_key == KIOCB_SYNC_KEY;
+ return kiocb->ki_ctx == NULL;
}
static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
{
*kiocb = (struct kiocb) {
- .ki_users = 1,
- .ki_key = KIOCB_SYNC_KEY,
+ .ki_users = ATOMIC_INIT(1),
+ .ki_ctx = NULL,
.ki_filp = filp,
.ki_obj.tsk = current,
};
}
-#define AIO_RING_MAGIC 0xa10a10a1
-#define AIO_RING_COMPAT_FEATURES 1
-#define AIO_RING_INCOMPAT_FEATURES 0
-struct aio_ring {
- unsigned id; /* kernel internal index number */
- unsigned nr; /* number of io_events */
- unsigned head;
- unsigned tail;
-
- unsigned magic;
- unsigned compat_features;
- unsigned incompat_features;
- unsigned header_length; /* size of aio_ring */
-
-
- struct io_event io_events[0];
-}; /* 128 bytes + ring size */
-
-#define AIO_RING_PAGES 8
-struct aio_ring_info {
- unsigned long mmap_base;
- unsigned long mmap_size;
-
- struct page **ring_pages;
- spinlock_t ring_lock;
- long nr_pages;
-
- unsigned nr, tail;
-
- struct page *internal_pages[AIO_RING_PAGES];
-};
-
-static inline unsigned aio_ring_avail(struct aio_ring_info *info,
- struct aio_ring *ring)
-{
- return (ring->head + info->nr - 1 - ring->tail) % info->nr;
-}
-
-struct kioctx {
- atomic_t users;
- int dead;
- struct mm_struct *mm;
-
- /* This needs improving */
- unsigned long user_id;
- struct hlist_node list;
-
- wait_queue_head_t wait;
-
- spinlock_t ctx_lock;
-
- int reqs_active;
- 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;
-
- struct delayed_work wq;
-
- struct rcu_head rcu_head;
-};
-
/* prototypes */
-extern unsigned aio_max_size;
-
#ifdef CONFIG_AIO
extern ssize_t wait_on_sync_kiocb(struct kiocb *iocb);
-extern int aio_put_req(struct kiocb *iocb);
-extern void kick_iocb(struct kiocb *iocb);
-extern int aio_complete(struct kiocb *iocb, long res, long res2);
+extern void aio_put_req(struct kiocb *iocb);
+extern void aio_complete(struct kiocb *iocb, long res, long res2);
struct mm_struct;
extern void exit_aio(struct mm_struct *mm);
extern long do_io_submit(aio_context_t ctx_id, long nr,
struct iocb __user *__user *iocbpp, bool compat);
+void kiocb_set_cancel_fn(struct kiocb *req, kiocb_cancel_fn *cancel);
#else
static inline ssize_t wait_on_sync_kiocb(struct kiocb *iocb) { return 0; }
-static inline int aio_put_req(struct kiocb *iocb) { return 0; }
-static inline void kick_iocb(struct kiocb *iocb) { }
-static inline int aio_complete(struct kiocb *iocb, long res, long res2) { return 0; }
+static inline void aio_put_req(struct kiocb *iocb) { }
+static inline void aio_complete(struct kiocb *iocb, long res, long res2) { }
struct mm_struct;
static inline void exit_aio(struct mm_struct *mm) { }
static inline long do_io_submit(aio_context_t ctx_id, long nr,
struct iocb __user * __user *iocbpp,
bool compat) { return 0; }
+static inline void kiocb_set_cancel_fn(struct kiocb *req,
+ kiocb_cancel_fn *cancel) { }
#endif /* CONFIG_AIO */
static inline struct kiocb *list_kiocb(struct list_head *h)