nvme-rdma: limit the maximal queue size for RDMA controllers

Corrent limit of 1024 isn't valid for some of the RDMA based ctrls. In
case the target expose a cap of larger amount of entries (e.g. 1024),
the initiator may fail to create a QP with this size. Thus limit to a
value that works for all RDMA adapters.

Future general solution should use RDMA/core API to calculate this size
according to device capabilities and number of WRs needed per NVMe IO
request.

Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
index 1624da3..027ee57 100644
--- a/drivers/nvme/host/rdma.c
+++ b/drivers/nvme/host/rdma.c
@@ -1112,6 +1112,13 @@ static int nvme_rdma_setup_ctrl(struct nvme_rdma_ctrl *ctrl, bool new)
 			ctrl->ctrl.opts->queue_size, ctrl->ctrl.sqsize + 1);
 	}
 
+	if (ctrl->ctrl.sqsize + 1 > NVME_RDMA_MAX_QUEUE_SIZE) {
+		dev_warn(ctrl->ctrl.device,
+			"ctrl sqsize %u > max queue size %u, clamping down\n",
+			ctrl->ctrl.sqsize + 1, NVME_RDMA_MAX_QUEUE_SIZE);
+		ctrl->ctrl.sqsize = NVME_RDMA_MAX_QUEUE_SIZE - 1;
+	}
+
 	if (ctrl->ctrl.sqsize + 1 > ctrl->ctrl.maxcmd) {
 		dev_warn(ctrl->ctrl.device,
 			"sqsize %u > ctrl maxcmd %u, clamping down\n",