[PATCH] nvme: send uevent once a multipath namespace is operational again

From: Hannes Reinecke <hare@suse.de>
To: Keith Busch <keith.busch@wdc.com>
Cc: Hannes Reinecke <hare@suse.de>, Sagi Grimberg <sagi@grimberg.me>,
	linux-nvme@lists.infradead.org, Christoph Hellwig <hch@lst.de>
Subject: [PATCH] nvme: send uevent once a multipath namespace is operational again
Date: Fri, 26 Feb 2021 09:05:38 +0100	[thread overview]
Message-ID: <20210226080538.108392-1-hare@suse.de> (raw)

In an all paths down scenario I/O will be requeued or aborted, and no
further I/O will be ongoing on this namespace.
This leaves the upper layers unable to determine if the namespace
becomes operational again eg. after a successful controller reset.
With this patch a 'change' uevent will be sent per multipathed namespace
once the underlying controller moved to LIVE and started I/O processing
by calling nvme_kick_requeue_lists().

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/nvme/host/multipath.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index 7d38f9272490..844d952bd86f 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -97,8 +97,12 @@ void nvme_kick_requeue_lists(struct nvme_ctrl *ctrl)
 
 	down_read(&ctrl->namespaces_rwsem);
 	list_for_each_entry(ns, &ctrl->namespaces, list) {
-		if (ns->head->disk)
-			kblockd_schedule_work(&ns->head->requeue_work);
+		if (!ns->head->disk)
+			continue;
+		kblockd_schedule_work(&ns->head->requeue_work);
+		if (ctrl->state == NVME_CTRL_LIVE)
+			kobject_uevent(&disk_to_dev(ns->head->disk)->kobj,
+				       KOBJ_CHANGE);
 	}
 	up_read(&ctrl->namespaces_rwsem);
 }
-- 
2.26.2


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