vhost: break out of polling loop on error

When ring parsing fails, we currently handle this
as ring empty condition. This means that we enable
kicks and recheck ring empty: if this not empty,
we re-start polling which of course will fail again.

Instead, let's return a negative error code and stop polling.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 10 insertions, 2 deletions

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 0f41c9195e9b..54096eef4840 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -98,7 +98,8 @@ static void tx_poll_start(struct vhost_net *net, struct socket *sock)
 static void handle_tx(struct vhost_net *net)
 {
         struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_TX];
-        unsigned head, out, in, s;
+        unsigned out, in, s;
+        int head;
         struct msghdr msg = {
                 .msg_name = NULL,
                 .msg_namelen = 0,
@@ -135,6 +136,9 @@ static void handle_tx(struct vhost_net *net)
                                          ARRAY_SIZE(vq->iov),
                                          &out, &in,
                                          NULL, NULL);
+                /* On error, stop handling until the next kick. */
+                if (head < 0)
+                        break;
                 /* Nothing new?  Wait for eventfd to tell us they refilled. */
                 if (head == vq->num) {
                         wmem = atomic_read(&sock->sk->sk_wmem_alloc);
@@ -192,7 +196,8 @@ static void handle_tx(struct vhost_net *net)
 static void handle_rx(struct vhost_net *net)
 {
         struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX];
-        unsigned head, out, in, log, s;
+        unsigned out, in, log, s;
+        int head;
         struct vhost_log *vq_log;
         struct msghdr msg = {
                 .msg_name = NULL,
@@ -228,6 +233,9 @@ static void handle_rx(struct vhost_net *net)
                                          ARRAY_SIZE(vq->iov),
                                          &out, &in,
                                          vq_log, &log);
+                /* On error, stop handling until the next kick. */
+                if (head < 0)
+                        break;
                 /* OK, now we need to know about added descriptors. */
                 if (head == vq->num) {
                         if (unlikely(vhost_enable_notify(vq))) {