From: Muchun Song <songmuchun@xxxxxxxxxxxxx> Subject: mm: introduce PAGEFLAGS_MASK to replace ((1UL << NR_PAGEFLAGS) - 1) Instead of hard-coding ((1UL << NR_PAGEFLAGS) - 1) everywhere, introducing PAGEFLAGS_MASK to make the code clear to get the page flags. Link: https://lkml.kernel.org/r/20210819150712.59948-1-songmuchun@xxxxxxxxxxxxx Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx> Reviewed-by: Roman Gushchin <guro@xxxxxx> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx> Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/page-flags.h | 4 +++- include/trace/events/page_ref.h | 4 ++-- lib/test_printf.c | 2 +- lib/vsprintf.c | 2 +- 4 files changed, 7 insertions(+), 5 deletions(-) --- a/include/linux/page-flags.h~mm-introduce-pageflags_mask-to-replace-1ul-nr_pageflags-1 +++ a/include/linux/page-flags.h @@ -178,6 +178,8 @@ enum pageflags { PG_reported = PG_uptodate, }; +#define PAGEFLAGS_MASK ((1UL << NR_PAGEFLAGS) - 1) + #ifndef __GENERATING_BOUNDS_H static inline unsigned long _compound_head(const struct page *page) @@ -868,7 +870,7 @@ static inline void ClearPageSlabPfmemall * alloc-free cycle to prevent from reusing the page. */ #define PAGE_FLAGS_CHECK_AT_PREP \ - (((1UL << NR_PAGEFLAGS) - 1) & ~__PG_HWPOISON) + (PAGEFLAGS_MASK & ~__PG_HWPOISON) #define PAGE_FLAGS_PRIVATE \ (1UL << PG_private | 1UL << PG_private_2) --- a/include/trace/events/page_ref.h~mm-introduce-pageflags_mask-to-replace-1ul-nr_pageflags-1 +++ a/include/trace/events/page_ref.h @@ -38,7 +38,7 @@ DECLARE_EVENT_CLASS(page_ref_mod_templat TP_printk("pfn=0x%lx flags=%s count=%d mapcount=%d mapping=%p mt=%d val=%d", __entry->pfn, - show_page_flags(__entry->flags & ((1UL << NR_PAGEFLAGS) - 1)), + show_page_flags(__entry->flags & PAGEFLAGS_MASK), __entry->count, __entry->mapcount, __entry->mapping, __entry->mt, __entry->val) @@ -88,7 +88,7 @@ DECLARE_EVENT_CLASS(page_ref_mod_and_tes TP_printk("pfn=0x%lx flags=%s count=%d mapcount=%d mapping=%p mt=%d val=%d ret=%d", __entry->pfn, - show_page_flags(__entry->flags & ((1UL << NR_PAGEFLAGS) - 1)), + show_page_flags(__entry->flags & PAGEFLAGS_MASK), __entry->count, __entry->mapcount, __entry->mapping, __entry->mt, __entry->val, __entry->ret) --- a/lib/test_printf.c~mm-introduce-pageflags_mask-to-replace-1ul-nr_pageflags-1 +++ a/lib/test_printf.c @@ -614,7 +614,7 @@ page_flags_test(int section, int node, i bool append = false; int i; - flags &= BIT(NR_PAGEFLAGS) - 1; + flags &= PAGEFLAGS_MASK; if (flags) { page_flags |= flags; snprintf(cmp_buf + size, BUF_SIZE - size, "%s", name); --- a/lib/vsprintf.c~mm-introduce-pageflags_mask-to-replace-1ul-nr_pageflags-1 +++ a/lib/vsprintf.c @@ -2019,7 +2019,7 @@ static const struct page_flags_fields pf static char *format_page_flags(char *buf, char *end, unsigned long flags) { - unsigned long main_flags = flags & (BIT(NR_PAGEFLAGS) - 1); + unsigned long main_flags = flags & PAGEFLAGS_MASK; bool append = false; int i; _
