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From: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"David S. Miller" <davem@davemloft.net>,
	devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org,
	qat-linux@intel.com, linux-crypto@vger.kernel.org,
	linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linaro-mm-sig@lists.linaro.org, amd-gfx@lists.freedesktop.org,
	linux-input@vger.kernel.org, linux-iio@vger.kernel.org,
	linux-rdma@vger.kernel.org, linux-nvdimm@lists.01.org,
	linux-nvme@lists.infradead.org, linux-pci@vger.kernel.org,
	platform-driver-x86@vger.kernel.org,
	linux-remoteproc@vger.kernel.org, sparclinux@vger.kernel.org,
	linux-scsi@vger.kernel.org, linux-usb@vger.kernel.org,
	linux-fbdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	linux-btrfs@vger.kernel.org, ceph-devel@vger.kernel.org,
	linux-wireless@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH v2 05/17] compat_ioctl: move more drivers to generic_compat_ioctl_ptrarg
Date: Wed, 12 Sep 2018 13:01:31 -0300	[thread overview]
Message-ID: <20180912130131.2c6581d5@coco.lan> (raw)
In-Reply-To: <20180912151134.436719-1-arnd@arndb.de>

Em Wed, 12 Sep 2018 17:08:52 +0200
Arnd Bergmann <arnd@arndb.de> 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.
> 
> 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.
> 
> 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.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---

>  drivers/media/rc/lirc_dev.c                 | 4 +---

> 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 = {
>  	.owner		= THIS_MODULE,
>  	.write		= ir_lirc_transmit_ir,
>  	.unlocked_ioctl	= ir_lirc_ioctl,
> -#ifdef CONFIG_COMPAT
> -	.compat_ioctl	= ir_lirc_ioctl,
> -#endif
> +	.compat_ioctl	= generic_compat_ioctl_ptrarg,
>  	.read		= ir_lirc_read,
>  	.poll		= ir_lirc_poll,
>  	.open		= 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 
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 ;-)

From 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

  parent reply	other threads:[~2018-09-12 16:01 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-12 15:01 [PATCH v2 01/17] compat_ioctl: add generic_compat_ioctl_ptrarg() Arnd Bergmann
2018-09-12 15:01 ` [PATCH v2 02/17] compat_ioctl: move drivers to generic_compat_ioctl_ptrarg Arnd Bergmann
2018-09-12 15:33   ` Jason Gunthorpe
2018-09-12 16:20     ` Arnd Bergmann
2018-09-12 18:13   ` Greg Kroah-Hartman
2018-09-16 19:07   ` Jarkko Sakkinen
2018-09-12 15:01 ` [PATCH v2 03/17] compat_ioctl: use correct compat_ptr() translation in drivers Arnd Bergmann
2018-09-12 18:13   ` Greg Kroah-Hartman
2018-09-13  0:48   ` Andrew Donnellan
2018-09-13 11:03   ` Felipe Balbi
2018-09-12 15:01 ` [PATCH v2 04/17] ceph: fix compat_ioctl for ceph_dir_operations Arnd Bergmann
2018-09-12 16:12   ` David Laight
2018-09-12 16:25     ` Arnd Bergmann
2018-09-13  0:48   ` Yan, Zheng
2018-09-12 15:08 ` [PATCH v2 05/17] compat_ioctl: move more drivers to generic_compat_ioctl_ptrarg Arnd Bergmann
2018-09-12 15:08   ` [PATCH v2 06/17] compat_ioctl: move rtc handling into rtc-dev.c Arnd Bergmann
2018-09-12 20:00     ` Alexandre Belloni
2018-09-12 15:08   ` [PATCH v2 07/17] compat_ioctl: move tape handling into drivers Arnd Bergmann
2018-09-12 15:08   ` [PATCH v2 08/17] compat_ioctl: remove keyboard ioctl translation Arnd Bergmann
2018-09-12 15:08   ` [PATCH v2 09/17] compat_ioctl: remove HIDIO translation Arnd Bergmann
2018-09-12 15:56   ` [PATCH v2 05/17] compat_ioctl: move more drivers to generic_compat_ioctl_ptrarg Jason Gunthorpe
2018-09-12 15:58   ` Daniel Vetter
2018-09-12 16:01   ` Mauro Carvalho Chehab [this message]
2018-09-12 18:13   ` Greg Kroah-Hartman
2018-09-14 14:23   ` David Sterba
2018-09-14 20:35   ` Darren Hart
2018-09-14 20:57     ` Al Viro
2018-09-18 17:51       ` Darren Hart
2018-09-18 17:59         ` Jason Gunthorpe
2018-09-24 20:18           ` Arnd Bergmann
2018-09-24 20:35             ` Jason Gunthorpe
2018-09-24 21:17               ` Arnd Bergmann
2018-09-17  9:33   ` Jonathan Cameron
2018-10-06  7:05   ` Bjorn Andersson
2018-09-12 15:13 ` [PATCH v2 10/17] compat_ioctl: remove translation for sound ioctls Arnd Bergmann
2018-09-12 15:13   ` [PATCH v2 11/17] compat_ioctl: remove isdn ioctl translation Arnd Bergmann
2018-09-12 15:13   ` [PATCH v2 12/17] compat_ioctl: remove IGNORE_IOCTL() Arnd Bergmann
2018-09-12 15:13   ` [PATCH v2 13/17] compat_ioctl: remove /dev/random commands Arnd Bergmann
2018-09-12 18:13     ` Greg Kroah-Hartman
2018-09-12 15:13   ` [PATCH v2 14/17] compat_ioctl: remove joystick ioctl translation Arnd Bergmann
2018-09-12 15:13   ` [PATCH v2 15/17] compat_ioctl: remove PCI " Arnd Bergmann
2018-09-12 15:13   ` [PATCH v2 16/17] compat_ioctl: remove /dev/raw " Arnd Bergmann
2018-09-12 15:13   ` [PATCH v2 17/17] compat_ioctl: remove last RAID handling code Arnd Bergmann
2018-09-13 13:37   ` [PATCH v2 10/17] compat_ioctl: remove translation for sound ioctls Takashi Iwai
2018-09-13  2:07 ` [PATCH v2 01/17] compat_ioctl: add generic_compat_ioctl_ptrarg() Al Viro
2018-09-13 10:29   ` Arnd Bergmann
2018-10-28 17:07     ` Al Viro
2018-10-29  9:50       ` Arnd Bergmann

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