[PATCH] aio: revert lock_kiocb()
lock_kiocb() was introduced to serialize retrying and cancellation. In the
process of doing so it tried to sleep waiting for KIF_LOCKED while holding
the ctx_lock spinlock. Recent fixes have ensured that multiple concurrent
retries won't be attempted for a given iocb. Cancel has other problems and
has no significant in-tree users that have been complaining about it. So
for the immediate future we'll revert sleeping with the lock held and will
address proper cancellation and retry serialization in the future.
Signed-off-by: Zach Brown <zach.brown@oracle.com>
Acked-by: Benjamin LaHaise <bcrl@kvack.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/aio.c b/fs/aio.c
index d6b1551..9fe7216 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -398,7 +398,7 @@
if (unlikely(!req))
return NULL;
- req->ki_flags = 1 << KIF_LOCKED;
+ req->ki_flags = 0;
req->ki_users = 2;
req->ki_key = 0;
req->ki_ctx = ctx;
@@ -547,25 +547,6 @@
return ioctx;
}
-static int lock_kiocb_action(void *param)
-{
- schedule();
- return 0;
-}
-
-static inline void lock_kiocb(struct kiocb *iocb)
-{
- wait_on_bit_lock(&iocb->ki_flags, KIF_LOCKED, lock_kiocb_action,
- TASK_UNINTERRUPTIBLE);
-}
-
-static inline void unlock_kiocb(struct kiocb *iocb)
-{
- kiocbClearLocked(iocb);
- smp_mb__after_clear_bit();
- wake_up_bit(&iocb->ki_flags, KIF_LOCKED);
-}
-
/*
* use_mm
* Makes the calling kernel thread take on the specified
@@ -796,9 +777,7 @@
* Hold an extra reference while retrying i/o.
*/
iocb->ki_users++; /* grab extra reference */
- lock_kiocb(iocb);
aio_run_iocb(iocb);
- unlock_kiocb(iocb);
if (__aio_put_req(ctx, iocb)) /* drop extra ref */
put_ioctx(ctx);
}
@@ -1542,7 +1521,6 @@
spin_lock_irq(&ctx->ctx_lock);
aio_run_iocb(req);
- unlock_kiocb(req);
if (!list_empty(&ctx->run_list)) {
/* drain the run list */
while (__aio_run_iocbs(ctx))
@@ -1674,7 +1652,6 @@
if (NULL != cancel) {
struct io_event tmp;
pr_debug("calling cancel\n");
- lock_kiocb(kiocb);
memset(&tmp, 0, sizeof(tmp));
tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user;
tmp.data = kiocb->ki_user_data;
@@ -1686,7 +1663,6 @@
if (copy_to_user(result, &tmp, sizeof(tmp)))
ret = -EFAULT;
}
- unlock_kiocb(kiocb);
} else
ret = -EINVAL;