lkml.org 
[lkml]   [2016]   [Jun]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH net-next V4 1/6] ptr_ring: support zero length ring
Date
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>
---
include/linux/ptr_ring.h | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h
index 562a65e..d78b8b8 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,
--
2.7.4
\
 
 \ /
  Last update: 2016-06-30 09:41    [W:0.055 / U:0.328 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site