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authorJason Wang <jasowang@redhat.com>2016-06-30 09:45:31 +0300
committerDavid S. Miller <davem@davemloft.net>2016-07-01 12:32:16 +0300
commit982fb490c298896d15e9323a882f34a57c11ff56 (patch)
tree453a3c8afc504c726462412c5b61cb90785c1069 /include/linux/ptr_ring.h
parent8dc7243abbf514e208aee1c0b430f35b866f8cc4 (diff)
downloadlinux-982fb490c298896d15e9323a882f34a57c11ff56.tar.xz
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: Jason Wang <jasowang@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/ptr_ring.h')
-rw-r--r--include/linux/ptr_ring.h6
1 files changed, 4 insertions, 2 deletions
diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h
index 562a65e8bcc0..d78b8b89c707 100644
--- a/include/linux/ptr_ring.h
+++ b/include/linux/ptr_ring.h
@@ -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,