ide-cd: fix missing residual count setting in DMA mode

This patch fixes the missing residual count setting in DMA mode,
which was introduced during the conversion to blk-end-request.
The residual count could be used by the request submitter.
So if it isn't set correctly, some upper layers does not work.
(e.g. wodim for CD burning.)

The bug is in only DMA mode.
In PIO mode, we are setting the residual count correctly,
so no need to fix.

Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Reported-by: Andreas Schwab <schwab@suse.de>
Tested-by: Andreas Schwab <schwab@suse.de>
Tested-by: Laura Garcia <nevola@gmail.com>
Tested-by: Borislav Petkov <petkovbb@googlemail.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/ide-cd.c

@@ -1207,9 +1207,13 @@ static ide_startstop_t cdrom_newpc_intr(ide_drive_t *drive)
 end_request:
 	if (blk_pc_request(rq)) {
 		unsigned long flags;
+		unsigned int dlen = rq->data_len;
+
+		if (dma)
+			rq->data_len = 0;
 
 		spin_lock_irqsave(&ide_lock, flags);
-		if (__blk_end_request(rq, 0, rq->data_len))
+		if (__blk_end_request(rq, 0, dlen))
 			BUG();
 		HWGROUP(drive)->rq = NULL;
 		spin_unlock_irqrestore(&ide_lock, flags);