block: stack unplug
MD raid1 prepares to dispatch request in unplug callback. If make_request in
low level queue also uses unplug callback to dispatch request, the low level
queue's unplug callback will not be called. Recheck the callback list helps
this case.
Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/blk-core.c b/block/blk-core.c
index 177ddcf..35bf4fe 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2913,17 +2913,16 @@
{
LIST_HEAD(callbacks);
- if (list_empty(&plug->cb_list))
- return;
+ while (!list_empty(&plug->cb_list)) {
+ list_splice_init(&plug->cb_list, &callbacks);
- list_splice_init(&plug->cb_list, &callbacks);
-
- while (!list_empty(&callbacks)) {
- struct blk_plug_cb *cb = list_first_entry(&callbacks,
+ while (!list_empty(&callbacks)) {
+ struct blk_plug_cb *cb = list_first_entry(&callbacks,
struct blk_plug_cb,
list);
- list_del(&cb->list);
- cb->callback(cb);
+ list_del(&cb->list);
+ cb->callback(cb);
+ }
}
}