compat_ioctl: block: handle cdrom compat ioctl in non-cdrom drivers

Various block drivers implement the CDROMMULTISESSION,
CDROM_GET_CAPABILITY, and CDROMEJECT ioctl commands, relying on the
block layer to handle compat_ioctl mode for them.

Move this into the drivers directly as a preparation for simplifying
the block layer later.

When only integer arguments or no arguments are passed, the
same handler can be used for .ioctl and .compat_ioctl, and
when only pointer arguments are passed, the newly added
blkdev_compat_ptr_ioctl can be used.

Reviewed-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

drivers/block/floppy.c

@@ -3879,6 +3879,9 @@ static int fd_compat_ioctl(struct block_device *bdev, fmode_t mode, unsigned int
 {
 	int drive = (long)bdev->bd_disk->private_data;
 	switch (cmd) {
+	case CDROMEJECT: /* CD-ROM eject */
+	case 0x6470:	 /* SunOS floppy eject */
+
 	case FDMSGON:
 	case FDMSGOFF:
 	case FDSETEMSGTRESH:

drivers/block/paride/pd.c

@@ -874,6 +874,7 @@ static const struct block_device_operations pd_fops = {
 	.open		= pd_open,
 	.release	= pd_release,
 	.ioctl		= pd_ioctl,
+	.compat_ioctl	= pd_ioctl,
 	.getgeo		= pd_getgeo,
 	.check_events	= pd_check_events,
 	.revalidate_disk= pd_revalidate

drivers/block/paride/pf.c

@@ -276,6 +276,7 @@ static const struct block_device_operations pf_fops = {
 	.open		= pf_open,
 	.release	= pf_release,
 	.ioctl		= pf_ioctl,
+	.compat_ioctl	= pf_ioctl,
 	.getgeo		= pf_getgeo,
 	.check_events	= pf_check_events,
 };

drivers/block/sunvdc.c

@@ -171,6 +171,7 @@ static const struct block_device_operations vdc_fops = {
 	.owner		= THIS_MODULE,
 	.getgeo		= vdc_getgeo,
 	.ioctl		= vdc_ioctl,
+	.compat_ioctl	= blkdev_compat_ptr_ioctl,
 };
 
 static void vdc_blk_queue_start(struct vdc_port *port)

drivers/block/xen-blkfront.c

@@ -2632,6 +2632,7 @@ static const struct block_device_operations xlvbd_block_fops =
 	.release = blkif_release,
 	.getgeo = blkif_getgeo,
 	.ioctl = blkif_ioctl,
+	.compat_ioctl = blkdev_compat_ptr_ioctl,
 };