[PATCH 03/18] pktcdvd: Check private request size before attaching to a queue

[Bart Van Assche <bart.vanassche@sandisk.com>]

Since the pktcdvd driver only supports request queues for which
struct scsi_request is the first member of their private request
data, refuse to register block layer queues for which the private
data is smaller than struct scsi_request.

References: commit 82ed4db499b8 ("block: split scsi_request out of struct request")
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Jens Axboe <axboe@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Omar Sandoval <osandov@fb.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: linux-block@vger.kernel.org
---
 drivers/block/pktcdvd.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 205b865ebeb9..4134bb54f6ad 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -2583,6 +2583,12 @@ static int pkt_new_dev(struct pktcdvd_device *pd, dev_t dev)
 	bdev = bdget(dev);
 	if (!bdev)
 		return -ENOMEM;
+	if (blk_queue_cmd_size(bdev_get_queue(bdev)) <
+	    sizeof(struct scsi_request)) {
+		WARN_ONCE(true, "Attempt to register a non-SCSI queue\n");
+		bdput(bdev);
+		return -EINVAL;
+	}
 	ret = blkdev_get(bdev, FMODE_READ | FMODE_NDELAY, NULL);
 	if (ret)
 		return ret;
-- 
2.12.2