[Intel-gfx] [PATCH] drm/i915: Prefault before locking pages in shmem_pwrite

[Chris Wilson]

Quoting Matthew Auld (2019-04-02 13:39:20)
> On Mon, 1 Apr 2019 at 14:39, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> >
> > If the user passes in a pointer to a GGTT mmaping of the same buffer
> > being written to, we can hit a deadlock in acquiring the shmemfs page
> > (once as the write destination and then as the read source).
> 
> And also shmem_fault, so cpu mmaping?

Possibly if I reorder the test to not deadlock on the mmap_gtt first :)
Let's find out!
-Chris