bsg: add a request_queue argument to scsi_cmd_ioctl()

bsg uses scsi_cmd_ioctl() for some SCSI/sg ioctl
commands. scsi_cmd_ioctl() gets a request queue from a gendisk
arguement. This prevents bsg being bound to SCSI devices that don't
have a gendisk (like OSD). This adds a request_queue argument to
scsi_cmd_ioctl(). The SCSI/sg ioctl commands doesn't use a gendisk so
it's safe for any SCSI devices to use scsi_cmd_ioctl().

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index db53b2c..a26ba07 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -548,16 +548,12 @@
 	return __blk_send_generic(q, bd_disk, GPCMD_START_STOP_UNIT, data);
 }
 
-int scsi_cmd_ioctl(struct file *file, struct gendisk *bd_disk, unsigned int cmd, void __user *arg)
+int scsi_cmd_ioctl(struct file *file, struct request_queue *q,
+		   struct gendisk *bd_disk, unsigned int cmd, void __user *arg)
 {
-	request_queue_t *q;
 	int err;
 
-	q = bd_disk->queue;
-	if (!q)
-		return -ENXIO;
-
-	if (blk_get_queue(q))
+	if (!q || blk_get_queue(q))
 		return -ENXIO;
 
 	switch (cmd) {