nvme-auth: check chap ctrl_key once constructed

ctrl ctrl_key member may be overwritten from a sysfs context driven
by the user. Once a queue local copy was created, use that instead
to minimize checks on a shared resource.
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/nvme/host/auth.c

@@ -333,7 +333,7 @@ static int nvme_auth_process_dhchap_success1(struct nvme_ctrl *ctrl,
 	struct nvmf_auth_dhchap_success1_data *data = chap->buf;
 	size_t size = sizeof(*data);
 
-	if (ctrl->ctrl_key)
+	if (chap->ctrl_key)
 		size += chap->hash_len;
 
 	if (size > CHAP_BUF_SIZE) {
@@ -811,7 +811,7 @@ static void nvme_queue_auth_work(struct work_struct *work)
 		goto fail2;
 	}
 
-	if (ctrl->ctrl_key) {
+	if (chap->ctrl_key) {
 		/* DH-HMAC-CHAP Step 5: send success2 */
 		dev_dbg(ctrl->device, "%s: qid %d send success2\n",
 			__func__, chap->qid);