ceph: fix get_ticket_handler() error handling

get_ticket_handler() returns a valid pointer or it returns
ERR_PTR(-ENOMEM) if kzalloc() fails.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Sage Weil <sage@newdream.net>

fs/ceph/auth_x.c

@@ -376,7 +376,7 @@ static void ceph_x_validate_tickets(struct ceph_auth_client *ac, int *pneed)
 
 		th = get_ticket_handler(ac, service);
 
-		if (!th) {
+		if (IS_ERR(th)) {
 			*pneed |= service;
 			continue;
 		}
@@ -399,6 +399,9 @@ static int ceph_x_build_request(struct ceph_auth_client *ac,
 	struct ceph_x_ticket_handler *th =
 		get_ticket_handler(ac, CEPH_ENTITY_TYPE_AUTH);
 
+	if (IS_ERR(th))
+		return PTR_ERR(th);
+
 	ceph_x_validate_tickets(ac, &need);
 
 	dout("build_request want %x have %x need %x\n",
@@ -450,7 +453,6 @@ static int ceph_x_build_request(struct ceph_auth_client *ac,
 			return -ERANGE;
 		head->op = cpu_to_le16(CEPHX_GET_PRINCIPAL_SESSION_KEY);
 
-		BUG_ON(!th);
 		ret = ceph_x_build_authorizer(ac, th, &xi->auth_authorizer);
 		if (ret)
 			return ret;
@@ -505,7 +507,8 @@ static int ceph_x_handle_reply(struct ceph_auth_client *ac, int result,
 
 	case CEPHX_GET_PRINCIPAL_SESSION_KEY:
 		th = get_ticket_handler(ac, CEPH_ENTITY_TYPE_AUTH);
-		BUG_ON(!th);
+		if (IS_ERR(th))
+			return PTR_ERR(th);
 		ret = ceph_x_proc_ticket_reply(ac, &th->session_key,
 					       buf + sizeof(*head), end);
 		break;
@@ -563,8 +566,8 @@ static int ceph_x_verify_authorizer_reply(struct ceph_auth_client *ac,
 	void *end = p + sizeof(au->reply_buf);
 
 	th = get_ticket_handler(ac, au->service);
-	if (!th)
-		return -EIO;  /* hrm! */
+	if (IS_ERR(th))
+		return PTR_ERR(th);
 	ret = ceph_x_decrypt(&th->session_key, &p, end, &reply, sizeof(reply));
 	if (ret < 0)
 		return ret;
@@ -626,7 +629,7 @@ static void ceph_x_invalidate_authorizer(struct ceph_auth_client *ac,
 	struct ceph_x_ticket_handler *th;
 
 	th = get_ticket_handler(ac, peer_type);
-	if (th && !IS_ERR(th))
+	if (!IS_ERR(th))
 		remove_ticket_handler(ac, th);
 }