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>
This commit is contained in:
Shaohua Li 2012-07-31 09:08:15 +02:00 committed by Jens Axboe
parent 9cbb175088
commit 2a7d5559b3
1 changed files with 7 additions and 8 deletions

View File

@ -2913,17 +2913,16 @@ static void flush_plug_callbacks(struct blk_plug *plug)
{
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);
}
}
}