[PATCH] umem: fix up unplugging.

From: Tao Guo
Date: Fri Dec 30 2011 - 10:10:39 EST


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@xxxxxxx>
---
drivers/block/umem.c | 33 ++++++++++++++++++++++++++++++++-
1 files changed, 32 insertions(+), 1 deletions(-)

diff --git a/drivers/block/umem.c b/drivers/block/umem.c
index aa27120..c3bf98e 100644
--- 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);

--
1.7.7

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/