Re: [PATCH] dma-buf: add support for compat ioctl

From	Daniel Vetter <daniel@ffwll.ch>
Newsgroups	linux.kernel
Subject	Re: [PATCH] dma-buf: add support for compat ioctl
Date	2017-02-22 20:10 +0100
Message-ID	<tdKsx-6mT-1@gated-at.bofh.it> (permalink)
References	(1 earlier) <tdiFX-37b-3@gated-at.bofh.it> <tdj8Z-3gZ-1@gated-at.bofh.it> <tdjLI-3P2-1@gated-at.bofh.it> <tdk53-3Wc-1@gated-at.bofh.it> <tdkeN-4fZ-105@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Tue, Feb 21, 2017 at 4:08 PM, Christian König
<deathsimple@vodafone.de> wrote:
> Am 21.02.2017 um 15:55 schrieb Marek Szyprowski:
>>
>> Dear All,
>>
>> On 2017-02-21 15:37, Marek Szyprowski wrote:
>>>
>>> Hi Christian,
>>>
>>> On 2017-02-21 14:59, Christian König wrote:
>>>>
>>>> Am 21.02.2017 um 14:21 schrieb Marek Szyprowski:
>>>>>
>>>>> Add compat ioctl support to dma-buf. This lets one to use
>>>>> DMA_BUF_IOCTL_SYNC
>>>>> ioctl from 32bit application on 64bit kernel. Data structures for both
>>>>> 32
>>>>> and 64bit modes are same, so there is no need for additional
>>>>> translation
>>>>> layer.
>>>>
>>>>
>>>> Well I might be wrong, but IIRC compat_ioctl was just optional and if
>>>> not specified unlocked_ioctl was called instead.
>>>>
>>>> If that is true your patch wouldn't have any effect at all.
>>>
>>>
>>> Well, then why I got -ENOTTY in the 32bit test app for this ioctl on
>>> 64bit ARM64 kernel without this patch?
>>>
>>
>> I've checked in fs/compat_ioctl.c, I see no fallback in
>> COMPAT_SYSCALL_DEFINE3,
>> so one has to provide compat_ioctl callback to have ioctl working with
>> 32bit
>> apps.
>
>
> Then my memory cheated on me.
>
> In this case the patch is Reviewed-by: Christian König
> <christian.koenig@amd.com>.

Since you have commit rights for drm-misc, care to push this to
drm-misc-next-fixes pls? Also I think this warrants a cc: stable,
clearly an obvious screw-up in creating this api on our side :( So
feel free to smash my ack on the patch.

Thanks, Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch

Thread

[PATCH] dma-buf: add support for compat ioctl Marek Szyprowski <m.szyprowski@samsung.com> - 2017-02-21 14:30 +0100
  Re: [PATCH] dma-buf: add support for compat ioctl Christian König <deathsimple@vodafone.de> - 2017-02-21 15:00 +0100
    Re: [PATCH] dma-buf: add support for compat ioctl Marek Szyprowski <m.szyprowski@samsung.com> - 2017-02-21 15:40 +0100
      Re: [PATCH] dma-buf: add support for compat ioctl Marek Szyprowski <m.szyprowski@samsung.com> - 2017-02-21 16:00 +0100
        Re: [PATCH] dma-buf: add support for compat ioctl Christian König <deathsimple@vodafone.de> - 2017-02-21 16:10 +0100
          Re: [PATCH] dma-buf: add support for compat ioctl Daniel Vetter <daniel@ffwll.ch> - 2017-02-22 20:10 +0100
            Re: [PATCH] dma-buf: add support for compat ioctl Sumit Semwal <sumit.semwal@linaro.org> - 2017-02-23 07:50 +0100

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