X-Git-Url: http://pileus.org/git/?a=blobdiff_plain;f=include%2Flinux%2Fmm.h;h=c1b7414c7bef7c0a2128edd30438e48974af40f3;hb=27ea0f781198a9c594b036abf406b65a4705d5f2;hp=f28f46eade6a642873246fea247f3f5455a18acb;hpb=4e13c5d0212f25d69a97606b9d5a85edb52a7737;p=~andy%2Flinux

diff --git a/include/linux/mm.h b/include/linux/mm.h
index f28f46eade6..c1b7414c7be 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)