Re: [PATCH 07/20] dma-buf: use inline lock for the dma-fence-array

["Christian König" <christian.koenig@amd.com>]

On 11/7/25 13:04, Philipp Stanner wrote:
> On Fri, 2025-10-31 at 14:16 +0100, Christian König wrote:
>> Just as proof of concept and minor cleanup.
> 
> I maintain that even relatively simple commits should give a new reader
> ore one who's browsing through the log in 3 years a rough idea what's
> going on.
> 
> That is: quickly describe what the situation (motivation) is and what
> the commit does.
> 
> At the very least "proof of concept" is nothing anyone would expect in
> a non-RFC patch. To me as a non-expert in dma-buf it's not clear at all
> whether this patch here is actually necessary, i.e., solves a problem. 

Proof of concept in the sense "I use this patch to test the concept with with the kernel unit tests and robots".

> I also don't see how replacing one lock position with another is a
> "cleanup". Sharing spinlocks is perfectly legal and will remain so, no?

Well that's the more interesting question.

On the one hand I'm now pretty sure that allowing those shared fences was a really bad idea, there is simply no valid use case for them.

On the other hand changing all the existing implementations would be tons of work with limited gain. I already tried that before and without some intermediate solution like this here it would be an enormous patch set touching all current implementations at the same time.

Regards,
Christian.

> 
> P.
> 
>