From: Arnd Bergmann arnd@arndb.de
The __kernel_map_pages() function is mainly used for CONFIG_DEBUG_PAGEALLOC, but has a number of architecture specific definitions that may also be used in other configurations, as well as a global fallback definition for architectures that do not support DEBUG_PAGEALLOC.
When the option is disabled, any definitions without the prototype cause a warning:
mm/page_poison.c:102:6: error: no previous prototype for '__kernel_map_pages' [-Werror=missing-prototypes]
The function is a trivial nop here, so just declare it anyway to avoid the warning.
Signed-off-by: Arnd Bergmann arnd@arndb.de --- include/linux/mm.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h index 27ce77080c79..e95d7c575ea6 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3453,13 +3453,12 @@ static inline bool debug_pagealloc_enabled_static(void) return static_branch_unlikely(&_debug_pagealloc_enabled); }
-#ifdef CONFIG_DEBUG_PAGEALLOC /* * To support DEBUG_PAGEALLOC architecture must ensure that * __kernel_map_pages() never fails */ extern void __kernel_map_pages(struct page *page, int numpages, int enable); - +#ifdef CONFIG_DEBUG_PAGEALLOC static inline void debug_pagealloc_map_pages(struct page *page, int numpages) { if (debug_pagealloc_enabled_static())