cdrom: Check SCSI passthrough support before reading audio

The CDROMREADAUDIO ioctl uses SCSI passthrough when the .disk
pointer has been set in struct cdrom_device_info. Hence check
whether SCSI passthrough is supported before submitting a SCSI
command. Note: both the ide-cd and sr drivers set the disk
pointer in struct cdrom_device_info but neither the pcd nor
the gdrom driver sets that pointer.

References: commit 82ed4db499b8 ("block: split scsi_request out of struct request")
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Omar Sandoval <osandov@fb.com>
Cc: linux-block@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index 76c952fd9ab9056250341da04d08c6b012e343e2..ff19cfc587f04a99191d937b3adeb6f7a6d880cc 100644 (file)
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -2178,6 +2178,12 @@ static int cdrom_read_cdda_bpc(struct cdrom_device_info *cdi, __u8 __user *ubuf,
        if (!q)
                return -ENXIO;
 
+       if (!blk_queue_scsi_passthrough(q)) {
+               WARN_ONCE(true,
+                         "Attempt read CDDA info through a non-SCSI queue\n");
+               return -EINVAL;
+       }
+
        cdi->last_sense = 0;
 
        while (nframes) {