quota: Push dqio_sem down to ->get_next_id()

Push down acquisition of dqio_sem into ->get_next_id() callback. Mostly
for consistency with other operations.

Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 3b3c7f0..332f702 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -2067,16 +2067,12 @@
 int dquot_get_next_id(struct super_block *sb, struct kqid *qid)
 {
 	struct quota_info *dqopt = sb_dqopt(sb);
-	int err;
 
 	if (!sb_has_quota_active(sb, qid->type))
 		return -ESRCH;
 	if (!dqopt->ops[qid->type]->get_next_id)
 		return -ENOSYS;
-	down_read(&dqopt->dqio_sem);
-	err = dqopt->ops[qid->type]->get_next_id(sb, qid);
-	up_read(&dqopt->dqio_sem);
-	return err;
+	return dqopt->ops[qid->type]->get_next_id(sb, qid);
 }
 EXPORT_SYMBOL(dquot_get_next_id);