virtio-net: don't respond to cpu hotplug notifier if we're not ready

[ Upstream commit 3ab098df35f8b98b6553edc2e40234af512ba877 ]

We're trying to re-configure the affinity unconditionally in cpu hotplug
callback. This may lead the issue during resuming from s3/s4 since

- virt queues haven't been allocated at that time.
- it's unnecessary since thaw method will re-configure the affinity.

Fix this issue by checking the config_enable and do nothing is we're not ready.

The bug were introduced by commit 8de4b2f3ae90c8fc0f17eeaab87d5a951b66ee17
(virtio-net: reset virtqueue affinity when doing cpu hotplug).

Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Reviewed-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 42d670a468f8..542c3f2d8400 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1097,6 +1097,11 @@ static int virtnet_cpu_callback(struct notifier_block *nfb,
 {
         struct virtnet_info *vi = container_of(nfb, struct virtnet_info, nb);
 
+        mutex_lock(&vi->config_lock);
+
+        if (!vi->config_enable)
+                goto done;
+
         switch(action & ~CPU_TASKS_FROZEN) {
         case CPU_ONLINE:
         case CPU_DOWN_FAILED:
@@ -1109,6 +1114,9 @@ static int virtnet_cpu_callback(struct notifier_block *nfb,
         default:
                 break;
         }
+
+done:
+        mutex_unlock(&vi->config_lock);
         return NOTIFY_OK;
 }