[PATCH net 2/2] virtio_net: fix missing lock protection on control_buf access

[Heng Qi]

Refactored the handling of control_buf to be within the cvq_lock
critical section, mitigating race conditions between reading device
responses and new command submissions.

Fixes: 6f45ab3e0409 ("virtio_net: Add a lock for the command VQ.")
Signed-off-by: Heng Qi <hen...@linux.alibaba.com>
---
 drivers/net/virtio_net.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 6b0512a628e0..3d8407d9e3d2 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -2686,6 +2686,7 @@ static bool virtnet_send_command_reply(struct 
virtnet_info *vi, u8 class, u8 cmd
 {
        struct scatterlist *sgs[5], hdr, stat;
        u32 out_num = 0, tmp, in_num = 0;
+       bool ret;
        int err;
 
        /* Caller should know better */
@@ -2731,8 +2732,9 @@ static bool virtnet_send_command_reply(struct 
virtnet_info *vi, u8 class, u8 cmd
        }
 
 unlock:
+       ret = vi->ctrl->status == VIRTIO_NET_OK;
        mutex_unlock(&vi->cvq_lock);
-       return vi->ctrl->status == VIRTIO_NET_OK;
+       return ret;
 }
 
 static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
-- 
2.32.0.3.g01195cf9f