block: Fix regression in sed-opal for a saved key.

The commit 3bfeb612
introduced the use of keyring for sed-opal.

Unfortunately, there is also a possibility to save
the Opal key used in opal_lock_unlock().

This patch switches the order of operation, so the cached
key is used instead of failure for opal_get_key.

The problem was found by the cryptsetup Opal test recently
added to the cryptsetup tree.

Fixes: 3bfeb612 ("block: sed-opal: keyring support for SED keys")
Tested-by: Ondrej Kozina <okozina@redhat.com>
Signed-off-by: Milan Broz <gmazyland@gmail.com>
Link: https://lore.kernel.org/r/20231003100209.380037-1-gmazyland@gmail.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

block/sed-opal.c

@@ -2888,12 +2888,11 @@ static int opal_lock_unlock(struct opal_dev *dev,
 	if (lk_unlk->session.who > OPAL_USER9)
 		return -EINVAL;
 
-	ret = opal_get_key(dev, &lk_unlk->session.opal_key);
-	if (ret)
-		return ret;
 	mutex_lock(&dev->dev_lock);
 	opal_lock_check_for_saved_key(dev, lk_unlk);
-	ret = __opal_lock_unlock(dev, lk_unlk);
+	ret = opal_get_key(dev, &lk_unlk->session.opal_key);
+	if (!ret)
+		ret = __opal_lock_unlock(dev, lk_unlk);
 	mutex_unlock(&dev->dev_lock);
 
 	return ret;