nvmet: add helpers to set the result field for connect commands

The code to set the result field for the admin and I/O connect commands
is not only verbose and duplicated, but also violates the aliasing
rules as it accesses both the u16 and u32 members in the union.

Add a little helper to sort all that out.

Fixes: db1312dd9548 ("nvmet: implement basic In-Band Authentication")
Signed-off-by: Christoph Hellwig <[e-mail]>
Reviewed-by: Sagi Grimberg <[e-mail]>
Reviewed-by: Hannes Reinecke <[e-mail]>

drivers/nvme/target/fabrics-cmd.c

···
 	return ret;
 }
 
+static u32 nvmet_connect_result(struct nvmet_ctrl *ctrl)
+{
+	return (u32)ctrl->cntlid |
+		(nvmet_has_auth(ctrl) ? NVME_CONNECT_AUTHREQ_ATR : 0);
+}
+
 static void nvmet_execute_admin_connect(struct nvmet_req *req)
 {
 	struct nvmf_connect_command *c = &req->cmd->connect;
···
 		ctrl->cntlid, ctrl->subsys->subsysnqn, ctrl->hostnqn,
 		ctrl->pi_support ? " T10-PI is enabled" : "",
 		nvmet_has_auth(ctrl) ? " with DH-HMAC-CHAP" : "");
-	req->cqe->result.u16 = cpu_to_le16(ctrl->cntlid);
-
-	if (nvmet_has_auth(ctrl))
-		req->cqe->result.u32 |= cpu_to_le32(NVME_CONNECT_AUTHREQ_ATR);
+	req->cqe->result.u32 = cpu_to_le32(nvmet_connect_result(ctrl));
 out:
 	kfree(d);
 complete:
···
 	if (status)
 		goto out_ctrl_put;
 
-	/* pass back cntlid for successful completion */
-	req->cqe->result.u16 = cpu_to_le16(ctrl->cntlid);
-
 	pr_debug("adding queue %d to ctrl %d.\n", qid, ctrl->cntlid);
-	if (nvmet_has_auth(ctrl))
-		req->cqe->result.u32 |= cpu_to_le32(NVME_CONNECT_AUTHREQ_ATR);
-
+	req->cqe->result.u32 = cpu_to_le32(nvmet_connect_result(ctrl));
 out:
 	kfree(d);
 complete: