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
next prev parent reply other threads:[~2018-09-12 16:01 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20180912150142.157913-1-arnd@arndb.de>
2018-09-12 15:08 ` [PATCH v2 05/17] compat_ioctl: move more drivers to generic_compat_ioctl_ptrarg Arnd Bergmann
2018-09-12 15:56 ` 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
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