From: Jason Wang <jasowang@redhat.com>
To: mst@redhat.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, davem@davemloft.net
Cc: kvm@vger.kernel.org, virtualization@lists.linux-foundation.org,
eric.dumazet@gmail.com, brouer@redhat.com,
Jason Wang <jasowang@redhat.com>
Subject: [PATCH net-next V4 1/6] ptr_ring: support zero length ring
Date: Thu, 30 Jun 2016 14:45:31 +0800 [thread overview]
Message-ID: <1467269136-8082-2-git-send-email-jasowang@redhat.com> (raw)
In-Reply-To: <1467269136-8082-1-git-send-email-jasowang@redhat.com>
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
next prev parent reply other threads:[~2016-06-30 6:45 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-30 6:45 [PATCH net-next V4 0/6] switch to use tx skb array in tun Jason Wang
2016-06-30 6:45 ` Jason Wang [this message]
2016-06-30 6:45 ` [PATCH net-next V4 2/6] skb_array: minor tweak Jason Wang
2016-06-30 6:45 ` [PATCH net-next V4 3/6] ptr_ring: support resizing multiple queues Jason Wang
2016-06-30 6:45 ` [PATCH net-next V4 4/6] skb_array: add wrappers for resizing Jason Wang
2016-06-30 6:45 ` [PATCH net-next V4 5/6] net: introduce NETDEV_CHANGE_TX_QUEUE_LEN Jason Wang
2016-06-30 16:33 ` John Fastabend
2016-06-30 6:45 ` [PATCH net-next V4 6/6] tun: switch to use skb array for tx Jason Wang
2016-06-30 15:45 ` [PATCH net-next V4 0/6] switch to use tx skb array in tun Michael S. Tsirkin
2016-07-01 6:04 ` Jason Wang
2016-07-01 9:40 ` David Miller
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