On Wed, Sep 17, 2025 at 8:31 AM Jason Wang jasowang@redhat.com wrote:
Commit 67a873df0c41 ("vhost: basic in order support") pass the number of used elem to vhost_net_rx_peek_head_len() to make sure it can signal the used correctly before trying to do busy polling. But it forgets to clear the count, this would cause the count run out of sync with handle_rx() and break the busy polling.
Fixing this by passing the pointer of the count and clearing it after the signaling the used.
Acked-by: Michael S. Tsirkin mst@redhat.com
Acked-by: Eugenio Pérez eperezma@redhat.com
Cc: stable@vger.kernel.org Fixes: 67a873df0c41 ("vhost: basic in order support") Signed-off-by: Jason Wang jasowang@redhat.com
drivers/vhost/net.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index c6508fe0d5c8..16e39f3ab956 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -1014,7 +1014,7 @@ static int peek_head_len(struct vhost_net_virtqueue *rvq, struct sock *sk) }
static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk,
bool *busyloop_intr, unsigned int count)
bool *busyloop_intr, unsigned int *count){ struct vhost_net_virtqueue *rnvq = &net->vqs[VHOST_NET_VQ_RX]; struct vhost_net_virtqueue *tnvq = &net->vqs[VHOST_NET_VQ_TX]; @@ -1024,7 +1024,8 @@ static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk,
if (!len && rvq->busyloop_timeout) { /* Flush batched heads first */
vhost_net_signal_used(rnvq, count);
vhost_net_signal_used(rnvq, *count);*count = 0; /* Both tx vq and rx socket were polled here */ vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, true);@@ -1180,7 +1181,7 @@ static void handle_rx(struct vhost_net *net)
do { sock_len = vhost_net_rx_peek_head_len(net, sock->sk,
&busyloop_intr, count);
&busyloop_intr, &count); if (!sock_len) break; sock_len += sock_hlen;-- 2.34.1