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

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
......@@ -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)
{
return r->queue[r->consumer];
if (likely(r->size))
return r->queue[r->consumer];
return NULL;
}
/* Note: callers invoking this in a loop must use a compiler barrier,
......
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