[PATCH] fix SG_IO bio leak

This patch fixes bio leaks in SG_IO. rq->bio can be changed after io
completion, so we need to reset rq->bio before calling blk_rq_unmap_user()

http://marc.theaimsgroup.com/?l=linux-kernel&m=116570666807983&w=2

Signed-off-by: FUJITA Tomonori <[e-mail]>
Signed-off-by: Jens Axboe <[e-mail]>

block/scsi_ioctl.c

···
 	struct request *rq;
 	char sense[SCSI_SENSE_BUFFERSIZE];
 	unsigned char cmd[BLK_MAX_CDB];
+	struct bio *bio;
 
 	if (hdr->interface_id != 'S')
 		return -EINVAL;
···
 	if (ret)
 		goto out;
 
+	bio = rq->bio;
 	rq->retries = 0;
 
 	start_time = jiffies;
···
 			hdr->sb_len_wr = len;
 	}
 
+	rq->bio = bio;
 	if (blk_rq_unmap_user(rq))
 		ret = -EFAULT;