make W=1 generates the following warning for mm/vmalloc.c mm/vmalloc.c:1599:6: warning: no previous prototype for ‘set_iounmap_nonlazy’ [-Wmissing-prototypes] void set_iounmap_nonlazy(void) ^~~~~~~~~~~~~~~~~~~ This is an arch-generic function only used by x86. On other arches, it's dead code. Include the header with the definition and make it x86-64 specific. Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> --- mm/vmalloc.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index a13ac524f6ff..0522a418b1c5 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -36,6 +36,7 @@ #include <linux/overflow.h> #include <linux/pgtable.h> #include <linux/uaccess.h> +#include <linux/io.h> #include <asm/tlbflush.h> #include <asm/shmparam.h> @@ -1592,6 +1593,7 @@ static DEFINE_MUTEX(vmap_purge_lock); /* for per-CPU blocks */ static void purge_fragmented_blocks_allcpus(void); +#ifdef CONFIG_X86_64 /* * called before a call to iounmap() if the caller wants vm_area_struct's * immediately freed. @@ -1600,6 +1602,7 @@ void set_iounmap_nonlazy(void) { atomic_long_set(&vmap_lazy_nr, lazy_max_pages()+1); } +#endif /* CONFIG_X86_64 */ /* * Purges all lazily-freed vmap areas. -- 2.26.2