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-rw-r--r--include/linux/highmem.h4
-rw-r--r--include/linux/page-flags.h42
-rw-r--r--mm/hugetlb.c2
-rw-r--r--mm/memory.c9
-rw-r--r--mm/page_io.c2
-rw-r--r--mm/swap_state.c2
6 files changed, 48 insertions, 13 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)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index db861d8b6c2..1a5642074e3 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 6a9c048f601..7bb70728bb5 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 3b97f685027..065c4480eaf 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 65b81c92738..ec42f01a8d0 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: