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

From	Christian König <deathsimple@vodafone.de>
Newsgroups	linux.kernel
Subject	Re: [PATCH] dma-buf: add support for compat ioctl
Date	2017-02-21 16:10 +0100
Message-ID	<tdkeN-4fZ-105@gated-at.bofh.it> (permalink)
References	<tdiFX-37b-5@gated-at.bofh.it> <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>
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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>.

Regards,
Christian.

>
> Best regards

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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