1 files changed, 23 insertions, 7 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index f28f46eade6a..a0df4295e171 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -175,7 +175,7 @@ extern unsigned int kobjsize(const void *objp);
  * Special vmas that are non-mergable, non-mlock()able.
  * Note: mm/huge_memory.c VM_NO_THP depends on this definition.
  */
-#define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_PFNMAP)
+#define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_PFNMAP | VM_MIXEDMAP)
 
 /*
  * mapping from the currently active vm_flags protection bits (the
@@ -399,8 +399,18 @@ static inline void compound_unlock_irqrestore(struct page *page,
 
 static inline struct page *compound_head(struct page *page)
 {
-        if (unlikely(PageTail(page)))
-                return page->first_page;
+        if (unlikely(PageTail(page))) {
+                struct page *head = page->first_page;
+
+                /*
+                 * page->first_page may be a dangling pointer to an old
+                 * compound page, so recheck that it is still a tail
+                 * page before returning.
+                 */
+                smp_rmb();
+                if (likely(PageTail(page)))
+                        return head;
+        }
         return page;
 }
 
@@ -757,7 +767,7 @@ static inline bool __cpupid_match_pid(pid_t task_pid, int cpupid)
 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
 static inline int page_cpupid_xchg_last(struct page *page, int cpupid)
 {
-        return xchg(&page->_last_cpupid, cpupid);
+        return xchg(&page->_last_cpupid, cpupid & LAST_CPUPID_MASK);
 }
 
 static inline int page_cpupid_last(struct page *page)
@@ -766,7 +776,7 @@ static inline int page_cpupid_last(struct page *page)
 }
 static inline void page_cpupid_reset_last(struct page *page)
 {
-        page->_last_cpupid = -1;
+        page->_last_cpupid = -1 & LAST_CPUPID_MASK;
 }
 #else
 static inline int page_cpupid_last(struct page *page)
@@ -1477,9 +1487,15 @@ static inline void pgtable_page_dtor(struct page *page)
 
 #if USE_SPLIT_PMD_PTLOCKS
 
+static struct page *pmd_to_page(pmd_t *pmd)
+{
+        unsigned long mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
+        return virt_to_page((void *)((unsigned long) pmd & mask));
+}
+
 static inline spinlock_t *pmd_lockptr(struct mm_struct *mm, pmd_t *pmd)
 {
-        return ptlock_ptr(virt_to_page(pmd));
+        return ptlock_ptr(pmd_to_page(pmd));
 }
 
 static inline bool pgtable_pmd_page_ctor(struct page *page)
@@ -1498,7 +1514,7 @@ static inline void pgtable_pmd_page_dtor(struct page *page)
         ptlock_free(page);
 }
 
-#define pmd_huge_pte(mm, pmd) (virt_to_page(pmd)->pmd_huge_pte)
+#define pmd_huge_pte(mm, pmd) (pmd_to_page(pmd)->pmd_huge_pte)
 
 #else