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

[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?

https://elixir.bootlin.com/linux/latest/A/ident/map_dma_buf

-- 
Best regards,
Dmitry