blk_end_request: changing xen-blkfront (take 4)

This patch converts xen-blkfront to use blk_end_request interfaces.
Related 'uptodate' arguments are converted to 'error'.

Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

drivers/block/xen-blkfront.c

@@ -452,7 +452,7 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
 	RING_IDX i, rp;
 	unsigned long flags;
 	struct blkfront_info *info = (struct blkfront_info *)dev_id;
-	int uptodate;
+	int error;
 
 	spin_lock_irqsave(&blkif_io_lock, flags);
 
@@ -477,13 +477,13 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
 
 		add_id_to_freelist(info, id);
 
-		uptodate = (bret->status == BLKIF_RSP_OKAY);
+		error = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO;
 		switch (bret->operation) {
 		case BLKIF_OP_WRITE_BARRIER:
 			if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
 				printk(KERN_WARNING "blkfront: %s: write barrier op failed\n",
 				       info->gd->disk_name);
-				uptodate = -EOPNOTSUPP;
+				error = -EOPNOTSUPP;
 				info->feature_barrier = 0;
 				xlvbd_barrier(info);
 			}
@@ -494,10 +494,8 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
 				dev_dbg(&info->xbdev->dev, "Bad return from blkdev data "
 					"request: %x\n", bret->status);
 
-			ret = end_that_request_first(req, uptodate,
-				req->hard_nr_sectors);
+			ret = __blk_end_request(req, error, blk_rq_bytes(req));
 			BUG_ON(ret);
-			end_that_request_last(req, uptodate);
 			break;
 		default:
 			BUG();