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authorJean-Philippe Brucker <jean-philippe.brucker@arm.com>2018-11-30 16:05:53 +0000
committerDavid S. Miller <davem@davemloft.net>2018-12-03 15:52:30 -0800
commite3f787189e10f5fafce77ba8aa948741ebb93c2b (patch)
tree44b0e172af8f8621f15351aa2307642ba6fe25cf /drivers/vhost
parent4763c9f926d8907beaacea4fd883c784696d84ef (diff)
vhost: fix IOTLB locking
Commit 78139c94dc8c ("net: vhost: lock the vqs one by one") moved the vq lock to improve scalability, but introduced a possible deadlock in vhost-iotlb. vhost_iotlb_notify_vq() now takes vq->mutex while holding the device's IOTLB spinlock. And on the vhost_iotlb_miss() path, the spinlock is taken while holding vq->mutex. Since calling vhost_poll_queue() doesn't require any lock, avoid the deadlock by not taking vq->mutex. Fixes: 78139c94dc8c ("net: vhost: lock the vqs one by one") Acked-by: Jason Wang <jasowang@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/vhost')
-rw-r--r--drivers/vhost/vhost.c3
1 files changed, 0 insertions, 3 deletions
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 3a5f81a66d34..6b98d8e3a5bf 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -944,10 +944,7 @@ static void vhost_iotlb_notify_vq(struct vhost_dev *d,
if (msg->iova <= vq_msg->iova &&
msg->iova + msg->size - 1 >= vq_msg->iova &&
vq_msg->type == VHOST_IOTLB_MISS) {
- mutex_lock(&node->vq->mutex);
vhost_poll_queue(&node->vq->poll);
- mutex_unlock(&node->vq->mutex);
-
list_del(&node->node);
kfree(node);
}