Messages in this thread | | | Date | Thu, 17 Sep 2020 08:31:10 -0300 | From | Jason Gunthorpe <> | Subject | Re: [Linaro-mm-sig] Changing vma->vm_file in dma_buf_mmap() |
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On Thu, Sep 17, 2020 at 10:09:12AM +0200, Daniel Vetter wrote:
> Yeah, but it doesn't work when forwarding from the drm chardev to the > dma-buf on the importer side, since you'd need a ton of different > address spaces. And you still rely on the core code picking up your > pgoff mangling, which feels about as risky to me as the vma file > pointer wrangling - if it's not consistently applied the reverse map > is toast and unmap_mapping_range doesn't work correctly for our needs.
I would think the pgoff has to be translated at the same time the vm->vm_file is changed?
The owner of the dma_buf should have one virtual address space and FD, all its dma bufs should be linked to it, and all pgoffs translated to that space.
Jason
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