1 files changed, 23 insertions, 0 deletions

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index a39b38ccdc97..69ed3cb1197a 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -143,6 +143,29 @@ static inline int page_cache_get_speculative(struct page *page)
         return 1;
 }
 
+/*
+ * Same as above, but add instead of inc (could just be merged)
+ */
+static inline int page_cache_add_speculative(struct page *page, int count)
+{
+        VM_BUG_ON(in_interrupt());
+
+#if !defined(CONFIG_SMP) && defined(CONFIG_CLASSIC_RCU)
+# ifdef CONFIG_PREEMPT
+        VM_BUG_ON(!in_atomic());
+# endif
+        VM_BUG_ON(page_count(page) == 0);
+        atomic_add(count, &page->_count);
+
+#else
+        if (unlikely(!atomic_add_unless(&page->_count, count, 0)))
+                return 0;
+#endif
+        VM_BUG_ON(PageCompound(page) && page != compound_head(page));
+
+        return 1;
+}
+
 static inline int page_freeze_refs(struct page *page, int count)
 {
         return likely(atomic_cmpxchg(&page->_count, count, 0) == count);