[PATCHv2] nvme: generate uevent once a multipath namespace is operational again

From: Hannes Reinecke <hare@suse.de>
To: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagi@grimberg.me>,
	Keith Busch <keith.busch@wdc.com>,
	linux-nvme@lists.infradead.org, Hannes Reinecke <hare@suse.de>
Subject: [PATCHv2] nvme: generate uevent once a multipath namespace is operational again
Date: Tue, 11 May 2021 10:03:08 +0200	[thread overview]
Message-ID: <20210511080308.6734-1-hare@suse.de> (raw)

In an all paths down scenario I/O will be requeued or aborted, so no
further I/O will be ongoing on this namespace.
This leaves upper layers like MD unable to determine if the namespace
becomes operational again after a successful controller reset.
This patch will send an uevent per multipathed namespace once the
underlying controller is LIVE, allowing MD to start resync.

Changes to v1:
- use disk_uevent() as suggested by hch

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/nvme/host/multipath.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index 0551796517e6..ecc99bd5f8ad 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -100,8 +100,11 @@ 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)
+			disk_uevent(ns->head->disk, KOBJ_CHANGE);
 	}
 	up_read(&ctrl->namespaces_rwsem);
 }
-- 
2.29.2


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