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Commit 982fb490 authored by Jason Wang's avatar Jason Wang Committed by David S. Miller
Browse files

ptr_ring: support zero length ring 



Sometimes, we need zero length ring. But current code will crash since
we don't do any check before accessing the ring. This patch fixes this.

Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 8dc7243a

include/linux/ptr_ring.h

+4 −2
Original line number Diff line number Diff line
@@ -102,7 +102,7 @@ static inline bool ptr_ring_full_bh(struct ptr_ring *r) 
 */

static inline int __ptr_ring_produce(struct ptr_ring *r, void *ptr)

{

	if (r->queue[r->producer])

	if (unlikely(!r->size) || r->queue[r->producer])

		return -ENOSPC;



	r->queue[r->producer++] = ptr;
@@ -164,7 +164,9 @@ static inline int ptr_ring_produce_bh(struct ptr_ring *r, void *ptr) 
 */

static inline void *__ptr_ring_peek(struct ptr_ring *r)

{

	if (likely(r->size))

		return r->queue[r->consumer];

	return NULL;

}



/* Note: callers invoking this in a loop must use a compiler barrier,