[PATCH v4 6/6] nvme: multipath: pr_notice when iopolicy changes

[John Meneghini]

Send a pr_notice when ever the iopolicy on a subsystem
is changed. This is important for support reasons. It
is fully expected that users will be changing the iopolicy
with active IO in progress.

Signed-off-by: John Meneghini <jmeneghi at redhat.com>
---
 drivers/nvme/host/multipath.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index e9330bb1990b..0286e44a081f 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -67,6 +67,10 @@ static int nvme_activate_iopolicy(struct nvme_subsystem *subsys, int iopolicy)
 		}
 	}
 	mutex_unlock(&subsys->lock);
+
+	pr_notice("%s: %s enable %d status %d for subsysnqn %s\n", __func__,
+			nvme_iopolicy_names[iopolicy], enable, ret, subsys->subnqn);
+
 	return ret;
 }
 
@@ -890,6 +894,8 @@ void nvme_subsys_iopolicy_update(struct nvme_subsystem *subsys, int iopolicy)
 {
 	struct nvme_ctrl *ctrl;
 
+	int old_iopolicy = READ_ONCE(subsys->iopolicy);
+
 	WRITE_ONCE(subsys->iopolicy, iopolicy);
 
 	mutex_lock(&nvme_subsystems_lock);
@@ -898,6 +904,10 @@ void nvme_subsys_iopolicy_update(struct nvme_subsystem *subsys, int iopolicy)
 		nvme_mpath_clear_ctrl_paths(ctrl);
 	}
 	mutex_unlock(&nvme_subsystems_lock);
+
+	pr_notice("%s: changed from %s to %s for subsysnqn %s\n", __func__,
+			nvme_iopolicy_names[old_iopolicy], nvme_iopolicy_names[iopolicy],
+			subsys->subnqn);
 }
 
 static ssize_t nvme_subsys_iopolicy_store(struct device *dev,
-- 
2.39.3