Messages in this thread | | | Date | Wed, 4 Apr 2012 14:46:56 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] umem: fix up unplugging. |
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On Fri, 30 Dec 2011 09:17:31 -0500
(Long delay...)
Tao Guo <glorioustao@gmail.com> wrote:
> We need to implement unplugging to make umem start to work, or I/O > will never be triggered. >
I take it from this that umem simply doesn't work at all?
If so, for how long has this been the case and should we just delete the thing?
> > --- a/drivers/block/umem.c > +++ b/drivers/block/umem.c > @@ -111,7 +111,8 @@ struct cardinfo { > int current_idx; > sector_t current_sector; > > - struct request_queue *queue; > + struct request_queue *queue; > + struct blk_plug_cb plug_cb; > > struct mm_page { > dma_addr_t page_dma; > @@ -513,6 +514,33 @@ static void process_page(unsigned long data) > } > } > > +static void mm_unplug(struct blk_plug_cb *cb) > +{ > + struct cardinfo *card = container_of(cb, struct cardinfo, plug_cb); > + > + spin_lock_irq(&card->lock); > + activate(card); > + spin_unlock_irq(&card->lock); > +} > + > +int mm_check_plugged(struct cardinfo *card) > +{ > + struct blk_plug *plug = current->plug; > + struct cardinfo *c; > + > + if (!plug) > + return 0; > + > + list_for_each_entry(c, &plug->cb_list, plug_cb.list) { > + if (c == card) > + return 1; > + } > + > + /* set up unplug callback */ > + list_add(&card->plug_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 +551,8 @@ 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; > @@ -884,6 +914,7 @@ static int __devinit mm_pci_probe(struct pci_dev *dev, > blk_queue_make_request(card->queue, mm_make_request); > card->queue->queue_lock = &card->lock; > card->queue->queuedata = card; > + card->plug_cb.callback = mm_unplug; > > tasklet_init(&card->tasklet, process_page, (unsigned long)card);
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