Since using scsi_req() is only allowed against request queues for
which struct scsi_request is the first member of their private
request data, refuse to submit SCSI commands against a queue for
which this is not the case.

References: commit 82ed4db499b8 ("block: split scsi_request out of struct request")
Signed-off-by: Bart Van Assche <redacted>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Cc: J. Bruce Fields <redacted>
Cc: Jeff Layton <redacted>
Cc: Jens Axboe <axboe@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Omar Sandoval <redacted>
Cc: linux-nfs@vger.kernel.org
Cc: linux-block@vger.kernel.org
---
 fs/nfsd/blocklayout.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/nfsd/blocklayout.c b/fs/nfsd/blocklayout.c
index fb5213afc854..38e14cf7e74a 100644
--- a/fs/nfsd/blocklayout.c
+++ b/fs/nfsd/blocklayout.c

@@ -219,6 +219,9 @@ static int nfsd4_scsi_identify_device(struct block_device *bdev,
 	u8 *buf, *d, type, assoc;
 	int error;
 
+	if (WARN_ON_ONCE(!blk_queue_scsi_pdu(q)))
+		return -EINVAL;
+
 	buf = kzalloc(bufflen, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;

-- 
2.12.2