Commit 1680e906 authored Jul 15, 2010 by Michael S. Tsirkin

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>

parent 7b3384fc

drivers/vhost/net.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -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: