[PATCH net 1/2] virtio-net: don't respond to cpu hotplug notifier if we're not ready

From: Jason Wang <jasowang@redhat.com>
To: virtualization@lists.linux-foundation.org,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	rusty@rustcorp.com.au, mst@redhat.com
Cc: Jason Wang <jasowang@redhat.com>,
	Wanlong Gao <gaowanlong@cn.fujitsu.com>
Subject: [PATCH net 1/2] virtio-net: don't respond to cpu hotplug notifier if we're not ready
Date: Mon, 14 Oct 2013 17:56:34 +0800	[thread overview]
Message-ID: <1381744595-26881-1-git-send-email-jasowang@redhat.com> (raw)

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).

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
The patch is need for 3.8 and above.
---
 drivers/net/virtio_net.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index defec2b..c4bc1cc 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1116,6 +1116,11 @@ 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:
@@ -1128,6 +1133,9 @@ static int virtnet_cpu_callback(struct notifier_block *nfb,
 	default:
 		break;
 	}
+
+done:
+	mutex_unlock(&vi->config_lock);
 	return NOTIFY_OK;
 }
 
-- 
1.8.1.2

