Re: [PATCH net] virtio_net: fix return value check in receive_mergeable()

[Jason Wang]

On 2017年12月04日 19:25, wangyunjian wrote:

-----Original Message-----
From: Jason Wang [mailto:jasow...@redhat.com]
Sent: Monday, December 04, 2017 3:10 PM
To: wangyunjian <wangyunj...@huawei.com>; linux-
ker...@vger.kernel.org
Cc: m...@redhat.com; caihe <ca...@huawei.com>
Subject: Re: [PATCH net] virtio_net: fix return value check in
receive_mergeable()



On 2017年12月04日 14:02, wangyunjian wrote:

From: Yunjian Wang <wangyunj...@huawei.com>

The function virtqueue_get_buf_ctx() could return NULL, the return
value 'buf' need to be checked with NULL, not value 'ctx'.

Signed-off-by: Yunjian Wang <wangyunj...@huawei.com>
---
   drivers/net/virtio_net.c | 2 +-
   1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 19a985e..559b215 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -756,7 +756,7 @@ static struct sk_buff *receive_mergeable(struct

net_device *dev,

                int num_skb_frags;

                buf = virtqueue_get_buf_ctx(rq->vq, &len, &ctx);
-               if (unlikely(!ctx)) {
+               if (unlikely(!buf)) {
                        pr_debug("%s: rx error: %d buffers out of %d

missing\n",

                                 dev->name, num_buf,
                                 virtio16_to_cpu(vi->vdev,

Hi:

The path looks good but I'm not sure this is a real fix since we add
data and ctx simultaneously in virtqueue_add_inbuf_ctx().

Any bad result you see without this patch?

Now no problem has been found yet, and I found it when reviewing the code.

Thanks

Then I think it's better to go net-next. Michael, any idea on this?

Thanks

Thanks