Re: [PATCH v2 05/17] compat_ioctl: move more drivers to generic_compat_ioctl_ptrarg
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From: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Date: 2018-09-12 16:01:31
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amd-gfx, ceph-devel, dri-devel, linux-btrfs, linux-crypto, linux-fbdev, linux-fsdevel, linux-input, linux-media, linux-pci, linux-rdma, linux-remoteproc, linux-scsi, linux-usb, linux-wireless, lkml, netdev, nvdimm, platform-driver-x86, sparclinux
Em Wed, 12 Sep 2018 17:08:52 +0200 Arnd Bergmann [off-list ref] escreveu:
The .ioctl and .compat_ioctl file operations have the same prototype so they can both point to the same function, which works great almost all the time when all the commands are compatible. =20 One exception is the s390 architecture, where a compat pointer is only 31 bit wide, and converting it into a 64-bit pointer requires calling compat_ptr(). Most drivers here will ever run in s390, but since we now have a generic helper for it, it's easy enough to use it consistently. =20 I double-checked all these drivers to ensure that all ioctl arguments are used as pointers or are ignored, but are not interpreted as integer values. =20 Signed-off-by: Arnd Bergmann <arnd@arndb.de> ---
drivers/media/rc/lirc_dev.c | 4 +---
quoted hunk ↗ jump to hunk
diff --git a/drivers/media/rc/lirc_dev.c b/drivers/media/rc/lirc_dev.c index f862f1b7f996..077209f414ed 100644 --- a/drivers/media/rc/lirc_dev.c +++ b/drivers/media/rc/lirc_dev.c@@ -730,9 +730,7 @@ static const struct file_operations lirc_fops =3D { .owner =3D THIS_MODULE, .write =3D ir_lirc_transmit_ir, .unlocked_ioctl =3D ir_lirc_ioctl, -#ifdef CONFIG_COMPAT - .compat_ioctl =3D ir_lirc_ioctl, -#endif + .compat_ioctl =3D generic_compat_ioctl_ptrarg, .read =3D ir_lirc_read, .poll =3D ir_lirc_poll, .open =3D ir_lirc_open,
Adding an infrared remote controller to a s390 mainframe sounds fun :-) I suspect that one could implement it on a s390 platform=20 using gpio-ir-recv and/or gpio-ir-tx drivers. Perhaps one possible practical usage would be to let the mainframe to send remote controller codes to adjust the air conditioning system ;-) =46rom lirc driver's PoV, there's nothing that really prevents one to do that and use lirc API, and the driver is generic enough to work on any hardware platform. I didn't check the implementation of generic_compat_ioctl_ptrarg(), but assuming it is ok, Acked-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Thanks, Mauro