On Wed, 2019-12-18 at 23:17 +0100, Arnd Bergmann wrote:
On Wed, Dec 18, 2019 at 10:11 PM Ben Hutchings ben.hutchings@codethink.co.uk wrote:
On Tue, 2019-12-17 at 23:17 +0100, Arnd Bergmann wrote:
Most of the HDIO ioctls are only used by the obsolete drivers/ide subsystem, these can be handled by changing ide_cmd_ioctl() to be aware of compat mode and doing the correct transformations in place and using it as both native and compat handlers for all drivers.
The SCSI drivers implementing the same commands are already doing this in the drivers, so the compat_blkdev_driver_ioctl() function is no longer needed now.
The BLKSECTSET and HDIO_GETGEO_BIG ioctls are not implemented in any driver any more and no longer need any conversion.
[...]
I noticed that HDIO_DRIVE_TASKFILE, handled by ide_taskfile_ioctl() in drivers/ide/ide-taskfile.c, never had compat handling before. After this patch it does, but its argument isn't passed through compat_ptr(). Again, doesn't really matter because IDE isn't a thing on s390.
I checked again, and I think it's worse than that: ide_taskfile_ioctl() takes an ide_task_request_t argument, which is not compatible at all (it has two long members). I suspect what happened here is that I confused it with ide_cmd_ioctl(), which takes a 'struct ide_taskfile' argument that /is/ compatible.
I don't think there is a point in adding a handler now: most users of drivers/ide are 32-bit only, and nobody complained so far, but I would add this change if you agree:
Looks good to me.
Ben.
diff --git a/drivers/ide/ide-ioctls.c b/drivers/ide/ide-ioctls.c index f6497c817493..83afee3983fe 100644 --- a/drivers/ide/ide-ioctls.c +++ b/drivers/ide/ide-ioctls.c @@ -270,6 +270,9 @@ int generic_ide_ioctl(ide_drive_t *drive, struct block_device *bdev, case HDIO_DRIVE_TASKFILE: if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO)) return -EACCES;
/* missing compat handler for HDIO_DRIVE_TASKFILE */if (in_compat_syscall())return -ENOTTY; if (drive->media == ide_disk) return ide_taskfile_ioctl(drive, arg); return -ENOMSG; Arnd