Re: [PATCH 1/6] dma-buf: add dynamic DMA-buf handling v10

Koenig, Christian
2019-06-25T07:20:12Z

Am 24.06.19 um 16:41 schrieb Daniel Vetter:
> On Mon, Jun 24, 2019 at 03:58:00PM +0200, Christian König wrote:
>> Am 24.06.19 um 13:23 schrieb Koenig, Christian:
>>> Am 21.06.19 um 18:27 schrieb Daniel Vetter:
>>>
>>>> So I pondered a few ideas while working out:
>>>>
>>>> 1) We drop this filtering. Importer needs to keep track of all its
>>>> mappings and filter out invalidates that aren't for that specific importer
>>>> (either because already invalidated, or not yet mapped, or whatever).
>>>> Feels fragile.
>>>>
>>>> [SNIP]
>>> [SNIP]
>>>
>>> I will take a moment and look into #1 as well, but I still don't see the
>>> need to change anything.
>> That turned out much cleaner than I thought it would be. Essentially it is
>> only a single extra line of code in amdgpu.
>>
>> Going to send that out as a patch set in a minute.
> Yeah I mean kinda expected that because:
> - everything's protected with ww_mutex anyway
> - importer needs to keep track of mappings anways
> So really all it needs to do is not be stupid and add the mapping it just
> created to its tracking while still holding the ww_mutex. Similar on
> invalidate/unmap.
>
> With that all we need is a huge note in the docs that importers need to
> keep track of their mappings and dtrt (with all the examples here spelled
> out in the appropriate kerneldoc). And then I'm happy :-)

Should I also rename the invalidate callback into move_notify? Would
kind of make sense since we are not necessary directly invalidating
mappings.

Christian.

>
> Cheers, Daniel