raid5: fix stripe release order

patch "make release_stripe lockless" changes the order stripes are released.
Originally I thought block layer can take care of request merge, but it appears
there are still some requests not merged. It's easy to fix the order.

Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 287cc3b..d87a2de 100644 (file)
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -239,6 +239,20 @@ static void __release_stripe(struct r5conf *conf, struct stripe_head *sh)
                do_release_stripe(conf, sh);
 }
 
+static struct llist_node *llist_reverse_order(struct llist_node *head)
+{
+       struct llist_node *new_head = NULL;
+
+       while (head) {
+               struct llist_node *tmp = head;
+               head = head->next;
+               tmp->next = new_head;
+               new_head = tmp;
+       }
+
+       return new_head;
+}
+
 /* should hold conf->device_lock already */
 static int release_stripe_list(struct r5conf *conf)
 {
@@ -247,6 +261,7 @@ static int release_stripe_list(struct r5conf *conf)
        struct llist_node *head;
 
        head = llist_del_all(&conf->released_stripes);
+       head = llist_reverse_order(head);
        while (head) {
                sh = llist_entry(head, struct stripe_head, release_list);
                head = llist_next(head);