diff options
| -rw-r--r-- | include/linux/highmem.h | 4 | ||||
| -rw-r--r-- | include/linux/page-flags.h | 42 | ||||
| -rw-r--r-- | mm/hugetlb.c | 2 | ||||
| -rw-r--r-- | mm/memory.c | 9 | ||||
| -rw-r--r-- | mm/page_io.c | 2 | ||||
| -rw-r--r-- | mm/swap_state.c | 2 |
6 files changed, 48 insertions, 13 deletions
diff --git a/include/linux/highmem.h b/include/linux/highmem.h index 61a5e5eb27f0..7dcbc82f3b7b 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 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) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index db861d8b6c28..1a5642074e34 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -813,6 +813,7 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, spin_unlock(&mm->page_table_lock); copy_huge_page(new_page, old_page, address, vma); + __SetPageUptodate(new_page); spin_lock(&mm->page_table_lock); ptep = huge_pte_offset(mm, address & HPAGE_MASK); @@ -858,6 +859,7 @@ retry: goto out; } clear_huge_page(page, address); + __SetPageUptodate(page); if (vma->vm_flags & VM_SHARED) { int err; diff --git a/mm/memory.c b/mm/memory.c index 6a9c048f6012..7bb70728bb52 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1518,10 +1518,8 @@ static inline void cow_user_page(struct page *dst, struct page *src, unsigned lo memset(kaddr, 0, PAGE_SIZE); kunmap_atomic(kaddr, KM_USER0); flush_dcache_page(dst); - return; - - } - copy_user_highpage(dst, src, va, vma); + } else + copy_user_highpage(dst, src, va, vma); } /* @@ -1630,6 +1628,7 @@ gotten: if (!new_page) goto oom; cow_user_page(new_page, old_page, address, vma); + __SetPageUptodate(new_page); /* * Re-check the pte - we dropped the lock @@ -2102,6 +2101,7 @@ static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, page = alloc_zeroed_user_highpage_movable(vma, address); if (!page) goto oom; + __SetPageUptodate(page); entry = mk_pte(page, vma->vm_page_prot); entry = maybe_mkwrite(pte_mkdirty(entry), vma); @@ -2202,6 +2202,7 @@ static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma, goto out; } copy_user_highpage(page, vmf.page, address, vma); + __SetPageUptodate(page); } else { /* * If the page will be shareable, see if the backing diff --git a/mm/page_io.c b/mm/page_io.c index 3b97f6850273..065c4480eaf0 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -126,7 +126,7 @@ int swap_readpage(struct file *file, struct page *page) int ret = 0; BUG_ON(!PageLocked(page)); - ClearPageUptodate(page); + BUG_ON(PageUptodate(page)); bio = get_swap_bio(GFP_KERNEL, page_private(page), page, end_swap_bio_read); if (bio == NULL) { diff --git a/mm/swap_state.c b/mm/swap_state.c index 65b81c92738f..ec42f01a8d02 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -125,6 +125,7 @@ int add_to_swap(struct page * page, gfp_t gfp_mask) int err; BUG_ON(!PageLocked(page)); + BUG_ON(!PageUptodate(page)); for (;;) { entry = get_swap_page(); @@ -147,7 +148,6 @@ int add_to_swap(struct page * page, gfp_t gfp_mask) switch (err) { case 0: /* Success */ - SetPageUptodate(page); SetPageDirty(page); return 1; case -EEXIST: |