On Mon, 9 Nov 2020 08:20:05 +0530 Anshuman Khandual <anshuman.khandual@xxxxxxx> wrote: > > > On 11/7/20 10:37 AM, Andrew Morton wrote: > > On Fri, 06 Nov 2020 08:19:36 +0800 kernel test robot <lkp@xxxxxxxxx> wrote: > > > >> tree/branch: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master > >> branch HEAD: 0a6f624a86e766a27d23cbb73c23be62231d10ff Add linux-next specific files for 20201105 > >> > >> Error/Warning reports: > >> > >> https://lore.kernel.org/linux-mm/202010281624.9m2gZw45-lkp@xxxxxxxxx > >> https://lore.kernel.org/linux-mm/202010290238.M1tDrV8p-lkp@xxxxxxxxx > >> https://lore.kernel.org/linux-mm/202010291054.WEZO3olr-lkp@xxxxxxxxx > >> https://lore.kernel.org/linux-mm/202011020749.5XQ3Hfzc-lkp@xxxxxxxxx > >> > >> ... > >> > >> mm/kasan/init.c:318:9: warning: variable 'pud' set but not used [-Wunused-but-set-variable] > >> > > > > This is because mm/kasan/init.c does > > > > static void kasan_free_pud(pud_t *pud_start, p4d_t *p4d) > > { > > pud_t *pud; > > int i; > > > > for (i = 0; i < PTRS_PER_PUD; i++) { > > pud = pud_start + i; > > if (!pud_none(*pud)) > > return; > > } > > > > pud_free(&init_mm, (pud_t *)page_to_virt(p4d_page(*p4d))); > > p4d_clear(p4d); > > } > > > > but arch/arm/include/asm/pgtable-2level.h does > > > > #define pud_none(pud) (0) > > > > The solution here is for the arm implementation to reference `pud'. > > Typically this is done via the use of an empty static inline C function > > rather than a macro. But really all of these > > > > #define pud_none(pud) (0) > > #define pud_bad(pud) (0) > > #define pud_present(pud) (1) > > #define pud_clear(pudp) do { } while (0) > > #define set_pud(pud,pudp) do { } while (0) > > > > should be thus converted. > > > > Could someone in arm world please attend to this? > > + Ard Biesheuvel <ardb@xxxxxxxxxx> > + Linus Walleij <linus.walleij@xxxxxxxxxx> > > There were some earlier discussions to solve this in a different way. > > https://lore.kernel.org/linux-mm/CACRpkdbAXCMTW--BmVs8SQ_u5baaeUob+U57E=4=CrMxWtMO2g@xxxxxxxxxxxxxx/ > > with a subsequent follow up patch. > > https://lore.kernel.org/linux-arm-kernel/20201106085157.11211-1-linus.walleij@xxxxxxxxxx/ Yes, but why? macros-pretending-to-be-functions just keep on causing problems and they're so unnecessary. Why not just write functions in the first place?? Did anyone try implementing that?
