Messages in this thread |  | | Date | Wed, 17 Jun 2020 12:29:40 -0300 | | From | Jason Gunthorpe <> | | Subject | Re: [Linaro-mm-sig] [PATCH 04/18] dma-fence: prime lockdep annotations |
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On Wed, Jun 17, 2020 at 09:57:54AM +0200, Daniel Vetter wrote:
> > At the very least I think there should be some big warning that > > dma_fence in notifiers should be avoided. > > Yeah I'm working on documentation, and also the notifiers here > hopefully make it clear it's massive pain. I think we could even make > a hard rule that dma_fence in mmu notifier outside of drivers/gpu is a > bug/misfeature.
Yep!
> Might be a good idea to add a MAINTAINERS entry with a K: regex > pattern, so that you can catch such modifiers. We do already have such > a pattern for dma-fence, to catch abuse. So if you want I could type > up a documentation patch for this, get your and others acks and the > dri-devel folks would enforce that the dma_fence_wait madness doesn't > leak beyond drivers/gpu
It seems like the best thing
> Oded has agreed to remove the dma-fence usage, since they really don't > need it (and all the baggage that comes with it), plain old completion > is enough for their use. This use is also why I added the regex to > MAINTAINERS, so that in the future we can catch people who try to use > dma_fence because it looks cute and useful, and are completely > oblivious to all the pain and headaches involved.
This is good!
Thanks, Jason
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