Merge tag 'gpio-v5.3-4' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux...

[linux-2.6-microblaze.git] / include / linux / mm_types.h

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 3a37a89..6a7a108 100644 (file)
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -159,7 +159,16 @@ struct page {
                        /** @pgmap: Points to the hosting device page map. */
                        struct dev_pagemap *pgmap;
                        void *zone_device_data;
-                       unsigned long _zd_pad_1;        /* uses mapping */
+                       /*
+                        * ZONE_DEVICE private pages are counted as being
+                        * mapped so the next 3 words hold the mapping, index,
+                        * and private fields from the source anonymous or
+                        * page cache page while the page is migrated to device
+                        * private memory.
+                        * ZONE_DEVICE MEMORY_DEVICE_FS_DAX pages also
+                        * use the mapping, index, and private fields when
+                        * pmem backed DAX files are mapped.
+                        */
                };
 
                /** @rcu_head: You can use this to free a page by RCU. */