Add a "cmd_len" parameter to the request, so that device drivers

don't have to try to figure it out for themselves.

Make ide-cd.c use it. 

drivers/block/scsi_ioctl.c

@@ -226,6 +226,7 @@ static int sg_io(request_queue_t *q, struct block_device *bdev,
 	/*
 	 * fill in request structure
 	 */
+	rq->cmd_len = hdr.cmd_len;
 	copy_from_user(rq->cmd, hdr.cmdp, hdr.cmd_len);
 	if (sizeof(rq->cmd) != hdr.cmd_len)
 		memset(rq->cmd + hdr.cmd_len, 0, sizeof(rq->cmd) - hdr.cmd_len);
@@ -348,6 +349,7 @@ static int sg_scsi_ioctl(request_queue_t *q, struct block_device *bdev,
 	 * get command and data to send to device, if any
 	 */
 	err = -EFAULT;
+	rq->cmd_len = cmdlen;
 	if (copy_from_user(rq->cmd, sic->data, cmdlen))
 		goto error;
 

drivers/ide/ide-cd.c

@@ -882,6 +882,15 @@ static ide_startstop_t cdrom_transfer_packet_command (ide_drive_t *drive,
 					  struct request *rq,
 					  ide_handler_t *handler)
 {
+	/*
+	 * FIXME! This should be 'rq->cmd_len' when that is reliable.
+	 *
+	 * This breaks for real 16-byte commands. however, lots of drives
+	 * currently break if we just send 16-bytes for 10/12 byte commands.
+	 */
+#define MAX_CDB_BYTES  12
+	int cmd_len = MAX_CDB_BYTES;
+
 	struct cdrom_info *info = drive->driver_data;
 	ide_startstop_t startstop;
 
@@ -906,7 +915,7 @@ static ide_startstop_t cdrom_transfer_packet_command (ide_drive_t *drive,
 	ide_set_handler(drive, handler, rq->timeout, cdrom_timer_expiry);
 
 	/* Send the command to the device. */
-	HWIF(drive)->atapi_output_bytes(drive, rq->cmd, sizeof(rq->cmd));
+	HWIF(drive)->atapi_output_bytes(drive, rq->cmd, cmd_len);
 
 	/* Start the DMA if need be */
 	if (info->dma)
@@ -3004,6 +3013,7 @@ static int ide_cdrom_prep_fs(request_queue_t *q, struct request *rq)
 	 */
 	rq->cmd[7] = (blocks >> 8) & 0xff;
 	rq->cmd[8] = blocks & 0xff;
+	rq->cmd_len = 10;
 	return BLKPREP_OK;
 }
 
@@ -3026,6 +3036,7 @@ static int ide_cdrom_prep_pc(struct request *rq)
 		c[2] = 0;
 		c[1] &= 0xe0;
 		c[0] += (READ_10 - READ_6);
+		rq->cmd_len = 10;
 		return BLKPREP_OK;
 	}
 

include/linux/blkdev.h

@@ -92,6 +92,7 @@ struct request {
 	/*
 	 * when request is used as a packet command carrier
 	 */
+	unsigned int cmd_len;
 	unsigned char cmd[16];
 
 	unsigned int data_len;