[PATCH] aio: ring wrapping simplification
Since the tail pointer in aio_ring structure never wrap ring size more than
once, so a simple compare is sufficient to wrap the index around. This avoid
a more expensive mod operation.
Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Suparna Bhattacharya <suparna@in.ibm.com>
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 9f807a5..40517f3 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -978,7 +978,8 @@
tail = info->tail;
event = aio_ring_event(info, tail, KM_IRQ0);
- tail = (tail + 1) % info->nr;
+ if (++tail >= info->nr)
+ tail = 0;
event->obj = (u64)(unsigned long)iocb->ki_obj.user;
event->data = iocb->ki_user_data;