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From: Max Gurtovoy <maxg@mellanox.com>
Date: Tue, 23 Jun 2020 17:55:25 +0300
Subject: [PATCH] nvme-rdma: assign completion vector correctly
Git-commit: 032a9966a22a3596addf81dacf0c1736dfedc32a
Patch-mainline: v5.8-rc3
References: jsc#SLE-15608

The completion vector index that is given during CQ creation can't
exceed the number of support vectors by the underlying RDMA device. This
violation currently can accure, for example, in case one will try to
connect with N regular read/write queues and M poll queues and the sum
of N + M > num_supported_vectors. This will lead to failure in establish
a connection to remote target. Instead, in that case, share a completion
vector between queues.

Signed-off-by: Max Gurtovoy <maxg@mellanox.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Hannes Reinecke <hare@suse.com>
---
 drivers/nvme/host/rdma.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
index f8f856dc0c67..13506a87a444 100644
--- a/drivers/nvme/host/rdma.c
+++ b/drivers/nvme/host/rdma.c
@@ -470,7 +470,7 @@ static int nvme_rdma_create_queue_ib(struct nvme_rdma_queue *queue)
 	 * Spread I/O queues completion vectors according their queue index.
 	 * Admin queues can always go on completion vector 0.
 	 */
-	comp_vector = idx == 0 ? idx : idx - 1;
+	comp_vector = (idx == 0 ? idx : idx - 1) % ibdev->num_comp_vectors;
 
 	/* Polling queues need direct cq polling context */
 	if (nvme_rdma_poll_queue(queue))
-- 
2.16.4