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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Hannes Reinecke <hare@suse.de>,
        Sagi Grimberg <sagi@grimberg.me>,
        Christoph Hellwig <hch@lst.de>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.8 073/464] nvme-multipath: fix logic for non-optimized paths
Date:   Mon, 17 Aug 2020 17:10:26 +0200
Message-Id: <20200817143837.268973244@linuxfoundation.org>
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From: Martin Wilck <mwilck@suse.com>

[ Upstream commit 3f6e3246db0e6f92e784965d9d0edb8abe6c6b74 ]

Handle the special case where we have exactly one optimized path,
which we should keep using in this case.

Fixes: 75c10e732724 ("nvme-multipath: round-robin I/O policy")
Signed off-by: Martin Wilck <mwilck@suse.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/nvme/host/multipath.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index 66509472fe06a..fe8f7f123fac7 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -246,6 +246,12 @@ static struct nvme_ns *nvme_round_robin_path(struct nvme_ns_head *head,
 			fallback = ns;
 	}
 
+	/* No optimized path found, re-check the current path */
+	if (!nvme_path_is_disabled(old) &&
+	    old->ana_state == NVME_ANA_OPTIMIZED) {
+		found = old;
+		goto out;
+	}
 	if (!fallback)
 		return NULL;
 	found = fallback;
-- 
2.25.1