block: convert to dequeueing model (easy ones)

plat-omap/mailbox, floppy, viocd, mspro_block, i2o_block and
mmc/card/queue are already pretty close to dequeueing model and can be
converted with simple changes.  Convert them.

While at it,

* xen-blkfront: !fs check moved downwards to share dequeue call with
  normal path.

* mspro_block: __blk_end_request(..., blk_rq_cur_byte()) converted to
  __blk_end_request_cur()

* mmc/card/queue: loop of __blk_end_request() converted to
  __blk_end_request_all()

[ Impact: dequeue in-flight request ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Alex Dubov <oakad@yahoo.com>
Cc: Markus Lidel <Markus.Lidel@shadowconnect.com>
Cc: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
index 7a72e75..4b70f1e 100644
--- a/drivers/mmc/card/queue.c
+++ b/drivers/mmc/card/queue.c
@@ -54,8 +54,11 @@
 
 		spin_lock_irq(q->queue_lock);
 		set_current_state(TASK_INTERRUPTIBLE);
-		if (!blk_queue_plugged(q))
+		if (!blk_queue_plugged(q)) {
 			req = elv_next_request(q);
+			if (req)
+				blkdev_dequeue_request(req);
+		}
 		mq->req = req;
 		spin_unlock_irq(q->queue_lock);
 
@@ -88,15 +91,12 @@
 {
 	struct mmc_queue *mq = q->queuedata;
 	struct request *req;
-	int ret;
 
 	if (!mq) {
 		printk(KERN_ERR "MMC: killing requests for dead queue\n");
 		while ((req = elv_next_request(q)) != NULL) {
-			do {
-				ret = __blk_end_request(req, -EIO,
-							blk_rq_cur_bytes(req));
-			} while (ret);
+			blkdev_dequeue_request(req);
+			__blk_end_request_all(req, -EIO);
 		}
 		return;
 	}