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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, Chao Leng <lengchao@huawei.com>,
        Sagi Grimberg <sagi@grimberg.me>,
        Christoph Hellwig <hch@lst.de>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 33/60] nvme-rdma: fix possible hang when failing to set io queues
Date:   Mon, 22 Mar 2021 13:28:21 +0100
Message-Id: <20210322121923.477871583@linuxfoundation.org>
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From: Sagi Grimberg <sagi@grimberg.me>

[ Upstream commit c4c6df5fc84659690d4391d1fba155cd94185295 ]

We only setup io queues for nvme controllers, and it makes absolutely no
sense to allow a controller (re)connect without any I/O queues.  If we
happen to fail setting the queue count for any reason, we should not allow
this to be a successful reconnect as I/O has no chance in going through.
Instead just fail and schedule another reconnect.

Reported-by: Chao Leng <lengchao@huawei.com>
Fixes: 711023071960 ("nvme-rdma: add a NVMe over Fabrics RDMA host driver")
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chao Leng <lengchao@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/nvme/host/rdma.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
index da6030010432..b8c0f75bfb7b 100644
--- a/drivers/nvme/host/rdma.c
+++ b/drivers/nvme/host/rdma.c
@@ -666,8 +666,11 @@ static int nvme_rdma_alloc_io_queues(struct nvme_rdma_ctrl *ctrl)
 		return ret;
 
 	ctrl->ctrl.queue_count = nr_io_queues + 1;
-	if (ctrl->ctrl.queue_count < 2)
-		return 0;
+	if (ctrl->ctrl.queue_count < 2) {
+		dev_err(ctrl->ctrl.device,
+			"unable to set any I/O queues\n");
+		return -ENOMEM;
+	}
 
 	dev_info(ctrl->ctrl.device,
 		"creating %d I/O queues.\n", nr_io_queues);
-- 
2.30.1