Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[~andy/linux] / include / linux / mm.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index f28f46eade6a642873246fea247f3f5455a18acb..c1b7414c7bef7c0a2128edd30438e48974af40f3 100644 (file)
--- 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)