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umem: fix up unplugging

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Fix a regression introduced by 7eaceaccab ("block: remove per-queue
plugging").  In that patch, Jens removed the whole mm_unplug_device()
function, which used to be the trigger to make umem start to work.

We need to implement unplugging to make umem start to work, or I/O will
never be triggered.

Signed-off-by: Tao Guo <Tao.Guo@emc.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Shaohua Li <shli@kernel.org>
Cc: <stable@vger.kernel.org>
Acked-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Tao Guo 2012-06-13 21:17:21 +02:00 committed by Jens Axboe
parent 047fe36052
commit 32587371ad
1 changed files with 40 additions and 0 deletions
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40
drivers/block/umem.c
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@ -513,6 +513,44 @@ static void process_page(unsigned long data)
}
}
struct mm_plug_cb {
struct blk_plug_cb cb;
struct cardinfo *card;
};
static void mm_unplug(struct blk_plug_cb *cb)
{
struct mm_plug_cb *mmcb = container_of(cb, struct mm_plug_cb, cb);
spin_lock_irq(&mmcb->card->lock);
activate(mmcb->card);
spin_unlock_irq(&mmcb->card->lock);
kfree(mmcb);
}
static int mm_check_plugged(struct cardinfo *card)
{
struct blk_plug *plug = current->plug;
struct mm_plug_cb *mmcb;
if (!plug)
return 0;
list_for_each_entry(mmcb, &plug->cb_list, cb.list) {
if (mmcb->cb.callback == mm_unplug && mmcb->card == card)
return 1;
}
/* Not currently on the callback list */
mmcb = kmalloc(sizeof(*mmcb), GFP_ATOMIC);
if (!mmcb)
return 0;
mmcb->card = card;
mmcb->cb.callback = mm_unplug;
list_add(&mmcb->cb.list, &plug->cb_list);
return 1;
}
static void mm_make_request(struct request_queue *q, struct bio *bio)
{
struct cardinfo *card = q->queuedata;
@ -523,6 +561,8 @@ static void mm_make_request(struct request_queue *q, struct bio *bio)
*card->biotail = bio;
bio->bi_next = NULL;
card->biotail = &bio->bi_next;
if (bio->bi_rw & REQ_SYNC || !mm_check_plugged(card))
activate(card);
spin_unlock_irq(&card->lock);
return;