[PATCH AUTOSEL 4.14 15/17] nvme-rdma: assign completion vector correctly

[Sasha Levin]

From: Max Gurtovoy <maxg at mellanox.com>

[ Upstream commit 032a9966a22a3596addf81dacf0c1736dfedc32a ]

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 at mellanox.com>
Signed-off-by: Christoph Hellwig <hch at lst.de>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 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 9fffe41ead500..c91bfd839cabe 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;
 
 	/* +1 for ib_stop_cq */
 	queue->ib_cq = ib_alloc_cq(ibdev, queue,
-- 
2.25.1