diff options
Diffstat (limited to 'include/linux/page-flags.h')
| -rw-r--r-- | include/linux/page-flags.h | 42 |
1 files changed, 39 insertions, 3 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 209d3a47f50f..bbad43fb8181 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -131,16 +131,52 @@ #define ClearPageReferenced(page) clear_bit(PG_referenced, &(page)->flags) #define TestClearPageReferenced(page) test_and_clear_bit(PG_referenced, &(page)->flags) -#define PageUptodate(page) test_bit(PG_uptodate, &(page)->flags) +static inline int PageUptodate(struct page *page) +{ + int ret = test_bit(PG_uptodate, &(page)->flags); + + /* + * Must ensure that the data we read out of the page is loaded + * _after_ we've loaded page->flags to check for PageUptodate. + * We can skip the barrier if the page is not uptodate, because + * we wouldn't be reading anything from it. + * + * See SetPageUptodate() for the other side of the story. + */ + if (ret) + smp_rmb(); + + return ret; +} + +static inline void __SetPageUptodate(struct page *page) +{ + smp_wmb(); + __set_bit(PG_uptodate, &(page)->flags); #ifdef CONFIG_S390 + page_clear_dirty(page); +#endif +} + static inline void SetPageUptodate(struct page *page) { +#ifdef CONFIG_S390 if (!test_and_set_bit(PG_uptodate, &page->flags)) page_clear_dirty(page); -} #else -#define SetPageUptodate(page) set_bit(PG_uptodate, &(page)->flags) + /* + * Memory barrier must be issued before setting the PG_uptodate bit, + * so that all previous stores issued in order to bring the page + * uptodate are actually visible before PageUptodate becomes true. + * + * s390 doesn't need an explicit smp_wmb here because the test and + * set bit already provides full barriers. + */ + smp_wmb(); + set_bit(PG_uptodate, &(page)->flags); #endif +} + #define ClearPageUptodate(page) clear_bit(PG_uptodate, &(page)->flags) #define PageDirty(page) test_bit(PG_dirty, &(page)->flags) |