[PATCH 13/13] drm/i915: don't clobber userspace memory before commiting to the pread

The pagemap.h prefault helpers do the prefaulting by simply writing some data into every page. Hence we should not prefault when we're not yet commited to to actually writing data to userspace. The problem is now that - we can't prefault while holding dev->struct_mutex for we could deadlock with

[PATCH 13/13] drm/i915: don't clobber userspace memory before commiting to the pread

The pagemap.h prefault helpers do the prefaulting by simply writing some data into every page. Hence we should not prefault when we're not yet commited to to actually writing data to userspace. The problem is now that - we can't prefault while holding dev->struct_mutex for we could deadlock with