mm: introduce page reference manipulation functions

[mirror_ubuntu-zesty-kernel.git] / include / linux / mm.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index f7fd64227d3a36d496ccff4d5ab720ba90a49132..997fc2e5d9d8b46eeb4efb6eb7d23b8418e43390 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -22,6 +22,7 @@
 #include <linux/resource.h>
 #include <linux/page_ext.h>
 #include <linux/err.h>
+#include <linux/page_ref.h>
 
 struct mempolicy;
 struct anon_vma;
@@ -386,8 +387,8 @@ static inline int pmd_devmap(pmd_t pmd)
  */
 static inline int put_page_testzero(struct page *page)
 {
-       VM_BUG_ON_PAGE(atomic_read(&page->_count) == 0, page);
-       return atomic_dec_and_test(&page->_count);
+       VM_BUG_ON_PAGE(page_ref_count(page) == 0, page);
+       return page_ref_dec_and_test(page);
 }
 
 /*
@@ -398,7 +399,7 @@ static inline int put_page_testzero(struct page *page)
  */
 static inline int get_page_unless_zero(struct page *page)
 {
-       return atomic_inc_not_zero(&page->_count);
+       return page_ref_add_unless(page, 1, 0);
 }
 
 extern int page_is_ram(unsigned long pfn);
@@ -486,11 +487,6 @@ static inline int total_mapcount(struct page *page)
 }
 #endif
 
-static inline int page_count(struct page *page)
-{
-       return atomic_read(&compound_head(page)->_count);
-}
-
 static inline struct page *virt_to_head_page(const void *x)
 {
        struct page *page = virt_to_page(x);
@@ -498,15 +494,6 @@ static inline struct page *virt_to_head_page(const void *x)
        return compound_head(page);
 }
 
-/*
- * Setup the page count before being freed into the page allocator for
- * the first time (boot or memory hotplug)
- */
-static inline void init_page_count(struct page *page)
-{
-       atomic_set(&page->_count, 1);
-}
-
 void __put_page(struct page *page);
 
 void put_pages_list(struct list_head *pages);
@@ -716,8 +703,8 @@ static inline void get_page(struct page *page)
         * Getting a normal page or the head of a compound page
         * requires to already have an elevated page->_count.
         */
-       VM_BUG_ON_PAGE(atomic_read(&page->_count) <= 0, page);
-       atomic_inc(&page->_count);
+       VM_BUG_ON_PAGE(page_ref_count(page) <= 0, page);
+       page_ref_inc(page);
 
        if (unlikely(is_zone_device_page(page)))
                get_zone_device_page(page);