From 041bd1a1fc737cd73b0b8a9f74909191a8acc9fe Mon Sep 17 00:00:00 2001 From: Daniel Wagner Date: Wed, 1 Sep 2021 11:25:24 +0200 Subject: [PATCH] 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 Signed-off-by: Christoph Hellwig --- drivers/nvme/host/core.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 1c98a2f590ea..4a3a33f5f11c 100644 --- 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); -- 2.34.1