dm raid: fix missing reconfig_mutex unlock in raid_ctr() error paths

In the error paths 'bad_stripe_cache' and 'bad_check_reshape',
'reconfig_mutex' is still held after raid_ctr() returns.

Fixes: 9dbd1aa3a81c ("dm raid: add reshaping support to the target")
Signed-off-by: Yu Kuai <[e-mail]>
Signed-off-by: Mike Snitzer <[e-mail]>

drivers/md/dm-raid.c

···
 	/* Try to adjust the raid4/5/6 stripe cache size to the stripe size */
 	if (rs_is_raid456(rs)) {
 		r = rs_set_raid456_stripe_cache(rs);
-		if (r)
+		if (r) {
+			mddev_unlock(&rs->md);
 			goto bad_stripe_cache;
+		}
 	}
 
 	/* Now do an early reshape check */
 	if (test_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags)) {
 		r = rs_check_reshape(rs);
-		if (r)
+		if (r) {
+			mddev_unlock(&rs->md);
 			goto bad_check_reshape;
+		}
 
 		/* Restore new, ctr requested layout to perform check */
 		rs_config_restore(rs, &rs_layout);
···
 			r = rs->md.pers->check_reshape(&rs->md);
 			if (r) {
 				ti->error = "Reshape check failed";
+				mddev_unlock(&rs->md);
 				goto bad_check_reshape;
 			}
 		}