mm: introduce put_user_page*(), placeholder versions

[linux.git] / include / linux / mm.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index c3c73b3c9adce5de8bd6df061259039824047257..e6b6be15609ec4cddadcbca0c5b3f4b107fd4b1a 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1007,6 +1007,30 @@ static inline void put_page(struct page *page)
                __put_page(page);
 }
 
+/**
+ * put_user_page() - release a gup-pinned page
+ * @page:            pointer to page to be released
+ *
+ * Pages that were pinned via get_user_pages*() must be released via
+ * either put_user_page(), or one of the put_user_pages*() routines
+ * below. This is so that eventually, pages that are pinned via
+ * get_user_pages*() can be separately tracked and uniquely handled. In
+ * particular, interactions with RDMA and filesystems need special
+ * handling.
+ *
+ * put_user_page() and put_page() are not interchangeable, despite this early
+ * implementation that makes them look the same. put_user_page() calls must
+ * be perfectly matched up with get_user_page() calls.
+ */
+static inline void put_user_page(struct page *page)
+{
+       put_page(page);
+}
+
+void put_user_pages_dirty(struct page **pages, unsigned long npages);
+void put_user_pages_dirty_lock(struct page **pages, unsigned long npages);
+void put_user_pages(struct page **pages, unsigned long npages);
+
 #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
 #define SECTION_IN_PAGE_FLAGS
 #endif