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authorMichael S. Tsirkin <mst@redhat.com>2010-07-15 14:19:12 +0200
committerMichael S. Tsirkin <mst@redhat.com>2010-07-15 14:26:12 +0200
commit1680e9063ea28099a1efa8ca11cee069cc7a9bc3 (patch)
tree92fda29b75a081151d6e460f7ae8ec874517b6e5 /drivers/vhost
parentvhost: add unlikely annotations to error path (diff)
downloadlinux-1680e9063ea28099a1efa8ca11cee069cc7a9bc3.tar.xz
linux-1680e9063ea28099a1efa8ca11cee069cc7a9bc3.zip
vhost-net: avoid flush under lock
We flush under vq mutex when changing backends. This creates a deadlock as workqueue being flushed needs this lock as well. https://bugzilla.redhat.com/show_bug.cgi?id=612421 Drop the vq mutex before flush: we have the device mutex which is sufficient to prevent another ioctl from touching the vq. Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'drivers/vhost')
-rw-r--r--drivers/vhost/net.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 2406377a6e5e..2764e0fbf29b 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -534,11 +534,16 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
rcu_assign_pointer(vq->private_data, sock);
vhost_net_enable_vq(n, vq);
done:
+ mutex_unlock(&vq->mutex);
+
if (oldsock) {
vhost_net_flush_vq(n, index);
fput(oldsock->file);
}
+ mutex_unlock(&n->dev.mutex);
+ return 0;
+
err_vq:
mutex_unlock(&vq->mutex);
err: