block: Enhance new plugging support to support general callbacks

md/raid requires an unplug callback, but as it does not uses
requests the current code cannot provide one.

So allow arbitrary callbacks to be attached to the blk_plug.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
This commit is contained in:
NeilBrown
2011-04-18 09:52:22 +02:00
committed by Jens Axboe
parent a1b49cb7e2
commit 048c9374a7
2 changed files with 26 additions and 1 deletions
+20
View File
@@ -2638,6 +2638,7 @@ void blk_start_plug(struct blk_plug *plug)
plug->magic = PLUG_MAGIC;
INIT_LIST_HEAD(&plug->list);
INIT_LIST_HEAD(&plug->cb_list);
plug->should_sort = 0;
/*
@@ -2678,6 +2679,24 @@ static void queue_unplugged(struct request_queue *q, unsigned int depth,
q->unplugged_fn(q);
}
static void flush_plug_callbacks(struct blk_plug *plug)
{
LIST_HEAD(callbacks);
if (list_empty(&plug->cb_list))
return;
list_splice_init(&plug->cb_list, &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);
}
}
void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
{
struct request_queue *q;
@@ -2688,6 +2707,7 @@ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
BUG_ON(plug->magic != PLUG_MAGIC);
flush_plug_callbacks(plug);
if (list_empty(&plug->list))
return;