Hi Andrew,

After merging the akpm-current tree, today's linux-next build (powerpc
ppc64_defconfig) produced this warning:

In file included from arch/powerpc/include/asm/mmu-hash64.h:23:0,
                 from arch/powerpc/include/asm/mmu.h:197,
                 from arch/powerpc/include/asm/lppaca.h:36,
                 from arch/powerpc/include/asm/paca.h:20,
                 from arch/powerpc/include/asm/hw_irq.h:41,
                 from arch/powerpc/include/asm/irqflags.h:11,
                 from include/linux/irqflags.h:15,
                 from include/linux/spinlock.h:53,
                 from include/linux/mmzone.h:7,
                 from include/linux/gfp.h:5,
                 from include/linux/mm.h:9,
                 from include/linux/mman.h:4,
                 from mm/madvise.c:8:
mm/madvise.c: In function 'swapin_walk_pte_entry':
arch/powerpc/include/asm/pgtable-ppc64.h:183:3: warning: statement with no effect [-Wunused-value]
   (((pte_t *) pmd_page_vaddr(*(dir))) + (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)))
   ^
arch/powerpc/include/asm/pgtable-ppc64.h:185:34: note: in expansion of macro 'pte_offset_kernel'
 #define pte_offset_map(dir,addr) pte_offset_kernel((dir), (addr))
                                  ^
mm/madvise.c:161:2: note: in expansion of macro 'pte_offset_map'
  pte_offset_map(walk->pmd, start & PMD_MASK);
  ^
mm/madvise.c:145:9: warning: unused variable 'orig_pte' [-Wunused-variable]
  pte_t *orig_pte = pte - ((start & (PMD_SIZE - 1)) >> PAGE_SHIFT);
         ^

Introduced by commit 17336ae3d58a ("madvise: cleanup swapin_walk_pmd_entry()")
-- 
Cheers,
Stephen Rothwell                    sfr@canb.auug.org.au