ide: another possible ide panic fix for blk-end-request

I have reviewed all blk-end-request patches again to confirm whether
there are any similar problems with the last week's ide-cd panic:
    http://lkml.org/lkml/2008/1/29/140

And I found a possible similar bug in ide-io change:
ide_end_drive_cmd() could be called for blk_pc_request() which could
have bios.  To complete such requests correctly, we need to pass
the actual size of the request.
Otherwise, __blk_end_request() returns 1 because the request still has
bios, and the system will BUG() unnecessarily.

The following patch fixes the bug and should be applied on top of
Linus' git.
Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: Borislav Petkov <petkovbb@googlemail.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/ide-io.c

@@ -388,7 +388,8 @@ void ide_end_drive_cmd (ide_drive_t *drive, u8 stat, u8 err)
 	spin_lock_irqsave(&ide_lock, flags);
 	HWGROUP(drive)->rq = NULL;
 	rq->errors = err;
-	if (__blk_end_request(rq, (rq->errors ? -EIO : 0), 0))
+	if (unlikely(__blk_end_request(rq, (rq->errors ? -EIO : 0),
+				       blk_rq_bytes(rq))))
 		BUG();
 	spin_unlock_irqrestore(&ide_lock, flags);
 }