nvme-rdma: send cntlid in the RDMA_CM_REQUEST Private Data

When sending a RDMA_CM_REQUEST, the NVMe RDMA Transport Specification
allows you to populate the cntlid field in the RDMA_CM_REQUEST Private
Data.

The cntlid is returned by the target on completion of the first
RDMA_CM_REQUEST command (which creates the admin queue).

The cntlid field can then be populated by the host when the I/O queues
are created (using additional RDMA_CM_REQUEST commands), such that the
target can perform extra validation for additional RDMA_CM_REQUEST
commands.

This additional error code and error message is also added, such that
nvme_rdma_cm_msg() will display the proper error message if the target
fails the RDMA_CM_REQUEST command because of this extra validation.

Signed-off-by: Niklas Cassel <[e-mail]>
Reviewed-by: Sagi Grimberg <[e-mail]>
Reviewed-by: Christoph Hellwig <[e-mail]>
Signed-off-by: Keith Busch <[e-mail]>

drivers/nvme/host/rdma.c

···
 		 */
 		priv.hrqsize = cpu_to_le16(queue->queue_size);
 		priv.hsqsize = cpu_to_le16(queue->ctrl->ctrl.sqsize);
+		/* cntlid should only be set when creating an I/O queue */
+		priv.cntlid = cpu_to_le16(ctrl->ctrl.cntlid);
 	}
 
 	ret = rdma_connect_locked(queue->cm_id, &param);

include/linux/nvme-rdma.h

···
 	NVME_RDMA_CM_NO_RSC		= 0x06,
 	NVME_RDMA_CM_INVALID_IRD	= 0x07,
 	NVME_RDMA_CM_INVALID_ORD	= 0x08,
+	NVME_RDMA_CM_INVALID_CNTLID	= 0x09,
 };
 
 static inline const char *nvme_rdma_cm_msg(enum nvme_rdma_cm_status status)
···
 		return "invalid IRD";
 	case NVME_RDMA_CM_INVALID_ORD:
 		return "Invalid ORD";
+	case NVME_RDMA_CM_INVALID_CNTLID:
+		return "invalid controller ID";
 	default:
 		return "unrecognized reason";
 	}
···
 	__le16		qid;
 	__le16		hrqsize;
 	__le16		hsqsize;
-	u8		rsvd[24];
+	__le16		cntlid;
+	u8		rsvd[22];
 };
 
 /**