diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/highmem.h | 4 | ||||
| -rw-r--r-- | include/linux/page-flags.h | 42 |
2 files changed, 39 insertions, 7 deletions
diff --git a/include/linux/highmem.h b/include/linux/highmem.h index 61a5e5eb27f..7dcbc82f3b7 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -68,8 +68,6 @@ static inline void clear_user_highpage(struct page *page, unsigned long vaddr) void *addr = kmap_atomic(page, KM_USER0); clear_user_page(addr, vaddr, page); kunmap_atomic(addr, KM_USER0); - /* Make sure this page is cleared on other CPU's too before using it */ - smp_wmb(); } #ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE @@ -172,8 +170,6 @@ static inline void copy_user_highpage(struct page *to, struct page *from, copy_user_page(vto, vfrom, vaddr, to); kunmap_atomic(vfrom, KM_USER0); kunmap_atomic(vto, KM_USER1); - /* Make sure this page is cleared on other CPU's too before using it */ - smp_wmb(); } #endif diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 209d3a47f50..bbad43fb818 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) |