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

[Bart Van Assche]

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.vanass...@sandisk.com>
Cc: Jens Axboe <ax...@fb.com>
Cc: Christoph Hellwig <h...@lst.de>
Cc: Omar Sandoval <osan...@fb.com>
Cc: Hannes Reinecke <h...@suse.com>
Cc: linux-bl...@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