[Linaro-mm-sig] [PATCH v2 3/5] dma-buf: Move all dma-bufs to dynamic locking specification

[Christian König]

Am 10.08.22 um 19:49 schrieb Dmitry Osipenko:
> On 8/10/22 14:30, Christian König wrote:
>> Am 25.07.22 um 17:18 schrieb Dmitry Osipenko:
>>> This patch moves the non-dynamic dma-buf users over to the dynamic
>>> locking specification. The strict locking convention prevents deadlock
>>> situation for dma-buf importers and exporters.
>>>
>>> Previously the "unlocked" versions of the dma-buf API functions weren't
>>> taking the reservation lock and this patch makes them to take the lock.
>>>
>>> Intel and AMD GPU drivers already were mapping imported dma-bufs under
>>> the held lock, hence the "locked" variant of the functions are added
>>> for them and the drivers are updated to use the "locked" versions.
>> In general "Yes, please", but that won't be that easy.
>>
>> You not only need to change amdgpu and i915, but all drivers
>> implementing the map_dma_buf(), unmap_dma_buf() callbacks.
>>
>> Auditing all that code is a huge bunch of work.
> Hm, neither of drivers take the resv lock in map_dma_buf/unmap_dma_buf.
> It's easy to audit them all and I did it. So either I'm missing
> something or it doesn't take much time to check them all. Am I really
> missing something?

Ok, so this is only changing map/unmap now?

In this case please separate this from the documentation change.

I would also drop the _locked postfix from the function name, just 
having _unlocked on all functions which are supposed to be called with 
the lock held should be sufficient.

Thanks for looking into this,
Christian.

>
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