Re: [PATCH v3 2/2] mm: redefine VM_* flag constants with BIT()

[SeongJae Park]

On Thu, 2 Oct 2025 09:29:37 +0200 David Hildenbrand <david@xxxxxxxxxx> wrote:

> On 01.10.25 18:51, SeongJae Park wrote:
> > On Wed, 1 Oct 2025 09:03:53 +0000 Jakub Acs <acsjakub@xxxxxxxxx> wrote:
> > 
> >> Make VM_* flag constant definitions consistent - unify all to use BIT()
> >> macro.
> >>
> >> This is a separete follow-up fix after we changed VM_MERGEABLE
> >> separately to isolate bugfix for easier backporting. As suggested by
> >> David in [1].
> >>
> >> [1]: https://lore.kernel.org/all/85f852f9-8577-4230-adc7-c52e7f479454@xxxxxxxxxx/
> >>
> >> Signed-off-by: Jakub Acs <acsjakub@xxxxxxxxx>
> >> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> >> Cc: David Hildenbrand <david@xxxxxxxxxx>
> >> Cc: Xu Xin <xu.xin16@xxxxxxxxxx>
> >> Cc: Chengming Zhou <chengming.zhou@xxxxxxxxx>
> >> Cc: Peter Xu <peterx@xxxxxxxxxx>
> >> Cc: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
> >> Cc: linux-mm@xxxxxxxxx
> >> Cc: linux-kernel@xxxxxxxxxxxxxxx
> >> ---
> >>   include/linux/mm.h | 66 +++++++++++++++++++++++-----------------------
> >>   1 file changed, 33 insertions(+), 33 deletions(-)
> >>
> >> diff --git a/include/linux/mm.h b/include/linux/mm.h
> >> index c6794d0e24eb..88cab3d7eea2 100644
> >> --- a/include/linux/mm.h
> >> +++ b/include/linux/mm.h
> >> @@ -246,56 +246,56 @@ extern unsigned int kobjsize(const void *objp);
> >>    * vm_flags in vm_area_struct, see mm_types.h.
> >>    * When changing, update also include/trace/events/mmflags.h
> >>    */
> >> -#define VM_NONE		0x00000000
> >> +#define VM_NONE		0
> > 
> > I'm wondering if it could be more consistent to use 0UL instead.
> 
> Not really required, and if we're switching to BIT already there is not 
> a lot of consistency to be had. Would be different if we were avoid 
> BIT() is in patch v2.

Agreed. :)


Thanks,
SJ

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