On Mon 13-11-17 16:42:06, Stephen Rothwell wrote:
> Hi Andrew,
>
> After merging the akpm-current tree, today's linux-next build (powerpc
> ppc64_defconfig) produced this warning:
>
> In file included from include/linux/mmzone.h:17:0,
> from include/linux/mempolicy.h:10,
> from mm/mempolicy.c:70:
> mm/mempolicy.c: In function 'mpol_to_str':
> include/linux/nodemask.h:107:41: warning: the address of 'nodes' will always
> evaluate as 'true' [-Waddress]
> #define nodemask_pr_args(maskp) (maskp) ? MAX_NUMNODES : 0, (maskp) ?
> (maskp)->bits : NULL
> ^
> mm/mempolicy.c:2817:11: note: in expansion of macro 'nodemask_pr_args'
> nodemask_pr_args(&nodes));
> ^
Hmm, this warning is quite surprising to me. Sure in this particular
case maskp will always be non-NULL so we always expand to
MAX_NUMNODES, maskp->bits
which is what we want. But we have other users which may be NULL. Does
anybody understan why this warns at all?
--
Michal Hocko
SUSE Labs
