Re: [PATCH V1 05/10] arch/kmap_atomic: Consolidate duplicate code
From: Al Viro <viro@zeniv.linux.org.uk>
Date: 2020-05-01 02:09:26
Also in:
dri-devel, linux-arm-kernel, linux-mips, lkml, sparclinux
On Thu, Apr 30, 2020 at 01:38:40PM -0700, ira.weiny@intel.com wrote:
From: Ira Weiny <ira.weiny@intel.com> Every arch has the same code to ensure atomic operations and a check for !HIGHMEM page. Remove the duplicate code by defining a core kmap_atomic() which only calls the arch specific kmap_atomic_high() when the page is high memory.
Err.... AFAICS, you've just silently changed the semantics for kmap_atomic_prot() here. And while most of the callers are converted, drivers/gpu/drm/ttm/ttm_bo_util.c one is not, so at the very least it's a bisect hazard... And I would argue that having kmap_atomic() differ from kmap_atomic_prot() wrt disabling preempt is asking for trouble.