From: Christoph Hellwig <hch@xxxxxx> Subject: asm-generic: improve the flush_dcache_page stub There is a magic ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE cpp symbol that guards non-stub availability of flush_dcache_pagge. Use that to check if flush_dcache_pagg is implemented. Link: http://lkml.kernel.org/r/20200515143646.3857579-8-hch@xxxxxx Signed-off-by: Christoph Hellwig <hch@xxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/asm-generic/cacheflush.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/include/asm-generic/cacheflush.h~asm-generic-improve-the-flush_dcache_page-stub +++ a/include/asm-generic/cacheflush.h @@ -2,8 +2,6 @@ #ifndef _ASM_GENERIC_CACHEFLUSH_H #define _ASM_GENERIC_CACHEFLUSH_H -#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0 - /* * The cache doesn't need to be flushed when TLB entries change when * the cache is mapped to physical memory, not virtual memory @@ -42,12 +40,14 @@ static inline void flush_cache_page(stru } #endif -#ifndef flush_dcache_page +#ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE static inline void flush_dcache_page(struct page *page) { } +#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0 #endif + #ifndef flush_dcache_mmap_lock static inline void flush_dcache_mmap_lock(struct address_space *mapping) { _
