From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> Subject: mm: constify page_count and page_ref_count Now that compound_head() accepts a const struct page pointer, these two functions can be marked as not modifying the page pointer they are passed. Link: https://lkml.kernel.org/r/20210416231531.2521383-7-willy@xxxxxxxxxxxxx Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx> Reviewed-by: Anshuman Khandual <anshuman.khandual@xxxxxxx> Reviewed-by: William Kucharski <william.kucharski@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/page_ref.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/include/linux/page_ref.h~mm-constify-page_count-and-page_ref_count +++ a/include/linux/page_ref.h @@ -62,12 +62,12 @@ static inline void __page_ref_unfreeze(s #endif -static inline int page_ref_count(struct page *page) +static inline int page_ref_count(const struct page *page) { return atomic_read(&page->_refcount); } -static inline int page_count(struct page *page) +static inline int page_count(const struct page *page) { return atomic_read(&compound_head(page)->_refcount); } _
