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-rw-r--r--mm/rmap.c23
1 files changed, 16 insertions, 7 deletions
diff --git a/mm/rmap.c b/mm/rmap.c
index f6f0d2d..92e6757 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -381,7 +381,13 @@ vma_address(struct page *page, struct vm_area_struct *vma)
unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
{
if (PageAnon(page)) {
- if (vma->anon_vma->root != page_anon_vma(page)->root)
+ struct anon_vma *page__anon_vma = page_anon_vma(page);
+ /*
+ * Note: swapoff's unuse_vma() is more efficient with this
+ * check, and needs it to match anon_vma when KSM is active.
+ */
+ if (!vma->anon_vma || !page__anon_vma ||
+ vma->anon_vma->root != page__anon_vma->root)
return -EFAULT;
} else if (page->mapping && !(vma->vm_flags & VM_NONLINEAR)) {
if (!vma->vm_file ||
@@ -1564,13 +1570,14 @@ static void __hugepage_set_anon_rmap(struct page *page,
struct vm_area_struct *vma, unsigned long address, int exclusive)
{
struct anon_vma *anon_vma = vma->anon_vma;
+
BUG_ON(!anon_vma);
- if (!exclusive) {
- struct anon_vma_chain *avc;
- avc = list_entry(vma->anon_vma_chain.prev,
- struct anon_vma_chain, same_vma);
- anon_vma = avc->anon_vma;
- }
+
+ if (PageAnon(page))
+ return;
+ if (!exclusive)
+ anon_vma = anon_vma->root;
+
anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON;
page->mapping = (struct address_space *) anon_vma;
page->index = linear_page_index(vma, address);
@@ -1581,6 +1588,8 @@ void hugepage_add_anon_rmap(struct page *page,
{
struct anon_vma *anon_vma = vma->anon_vma;
int first;
+
+ BUG_ON(!PageLocked(page));
BUG_ON(!anon_vma);
BUG_ON(address < vma->vm_start || address >= vma->vm_end);
first = atomic_inc_and_test(&page->_mapcount);
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