Subject: Re: linux-next: build warning after merge of the akpm-current tree

From: Michal Hocko <[email-masked]>
Date: Thu, 1 Aug 2019 08:15:28 +0200

On Thu 01-08-19 15:51:30, Stephen Rothwell wrote:
> Hi Miles,
> 
> On Wed, 31 Jul 2019 14:28:04 +0800 Miles Chen <[email-masked]> wrote:
> >
> > On Wed, 2019-07-31 at 16:11 +1000, Stephen Rothwell wrote:
> > > 
> > > After merging the akpm-current tree, today's linux-next build (powerpc
> > > ppc64_defconfig) produced this warning:
> > > 
> > > mm/memcontrol.c: In function 'invalidate_reclaim_iterators':
> > > mm/memcontrol.c:1160:11: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
> > >   } while (memcg = parent_mem_cgroup(memcg));
> > >            ^~~~~
> > >   
> > 
> > Hi Stephen,
> > 
> > Thanks for the telling me this. Sorry for the build warning. 
> > Should I send patch v5 to the mailing list to fix this? 
> 
> You might as well (cc'ing Andrew, of course).
> 
> I would suggest finishing that loop like this:
> 
> 		memcg = parent_mem_cgroup(memcg);
> 	} while (memcg);
> 
> rather than adding a set of parentheses.

Qian has already posted a patch http://lkml.kernel.org/r/[email-masked]
-- 
Michal Hocko
SUSE Labs