From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> Subject: mm/page_ext.c: constify lookup_page_ext() argument lookup_page_ext() finds 'struct page_ext' for a given page. It requires only read access to the given struct page. Current implemnentation takes 'struct page *' as an argument. It makes compiler complain when 'const struct page *' passed. Change the argument to 'const struct page *'. Link: http://lkml.kernel.org/r/20180531135457.20167-3-kirill.shutemov@xxxxxxxxxxxxxxx Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Vinayak Menon <vinmenon@xxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/page_ext.h | 4 ++-- mm/page_ext.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) --- a/include/linux/page_ext.h~mm-page_ext-constify-lookup_page_ext-argument +++ a/include/linux/page_ext.h @@ -50,7 +50,7 @@ static inline void page_ext_init(void) } #endif -struct page_ext *lookup_page_ext(struct page *page); +struct page_ext *lookup_page_ext(const struct page *page); #else /* !CONFIG_PAGE_EXTENSION */ struct page_ext; @@ -59,7 +59,7 @@ static inline void pgdat_page_ext_init(s { } -static inline struct page_ext *lookup_page_ext(struct page *page) +static inline struct page_ext *lookup_page_ext(const struct page *page) { return NULL; } --- a/mm/page_ext.c~mm-page_ext-constify-lookup_page_ext-argument +++ a/mm/page_ext.c @@ -120,7 +120,7 @@ void __meminit pgdat_page_ext_init(struc pgdat->node_page_ext = NULL; } -struct page_ext *lookup_page_ext(struct page *page) +struct page_ext *lookup_page_ext(const struct page *page) { unsigned long pfn = page_to_pfn(page); unsigned long index; @@ -195,7 +195,7 @@ fail: #else /* CONFIG_FLAT_NODE_MEM_MAP */ -struct page_ext *lookup_page_ext(struct page *page) +struct page_ext *lookup_page_ext(const struct page *page) { unsigned long pfn = page_to_pfn(page); struct mem_section *section = __pfn_to_section(pfn); _
