nvme: only call synchronize_srcu when clearing current path

The function nmve_mpath_clear_current_path returns true if the current
path has changed. In this case we have to wait for all concurrent
submissions to finish. But if we didn't change the current path, there
is no point in waiting for another RCU period to finish.

Signed-off-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 1c98a2f590ea8b51721c999d895e5ec77bfe3078..4a3a33f5f11c9b9498eca045adeabe0ddf594b96 100644 (file)
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -3838,9 +3838,12 @@ static void nvme_ns_remove(struct nvme_ns *ns)
        list_del_rcu(&ns->siblings);
        mutex_unlock(&ns->ctrl->subsys->lock);
 
-       synchronize_rcu(); /* guarantee not available in head->list */
-       nvme_mpath_clear_current_path(ns);
-       synchronize_srcu(&ns->head->srcu); /* wait for concurrent submissions */
+       /* guarantee not available in head->list */
+       synchronize_rcu();
+
+       /* wait for concurrent submissions */
+       if (nvme_mpath_clear_current_path(ns))
+               synchronize_srcu(&ns->head->srcu);
 
        if (!nvme_ns_head_multipath(ns->head))
                nvme_cdev_del(&ns->cdev, &ns->cdev_device);