nvme-auth: add flag for bi-directional auth

Introduces an explicit variable for bi-directional auth.
The currently used variable chap->s2 is incorrectly zeroed for
uni-directional auth. That will be fixed in the next patch so this
needs to change to avoid sending unexpected success2 messages
Signed-off-by: Mark O'Donovan <shiftee@posteo.net>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>

drivers/nvme/host/auth.c

@@ -29,6 +29,7 @@ struct nvme_dhchap_queue_context {
 	int error;
 	u32 s1;
 	u32 s2;
+	bool bi_directional;
 	u16 transaction;
 	u8 status;
 	u8 dhgroup_id;
@@ -312,6 +313,7 @@ static int nvme_auth_set_dhchap_reply_data(struct nvme_ctrl *ctrl,
 	data->dhvlen = cpu_to_le16(chap->host_key_len);
 	memcpy(data->rval, chap->response, chap->hash_len);
 	if (ctrl->ctrl_key) {
+		chap->bi_directional = true;
 		get_random_bytes(chap->c2, chap->hash_len);
 		data->cvalid = 1;
 		chap->s2 = nvme_auth_get_seqnum();
@@ -660,6 +662,7 @@ static void nvme_auth_reset_dhchap(struct nvme_dhchap_queue_context *chap)
 	chap->error = 0;
 	chap->s1 = 0;
 	chap->s2 = 0;
+	chap->bi_directional = false;
 	chap->transaction = 0;
 	memset(chap->c1, 0, sizeof(chap->c1));
 	memset(chap->c2, 0, sizeof(chap->c2));
@@ -822,7 +825,7 @@ static void nvme_queue_auth_work(struct work_struct *work)
 		goto fail2;
 	}
 
-	if (chap->s2) {
+	if (chap->bi_directional) {
 		/* DH-HMAC-CHAP Step 5: send success2 */
 		dev_dbg(ctrl->device, "%s: qid %d send success2\n",
 			__func__, chap->qid);