mm: Add is_migrate_cma_page

Code such as hardened user copy[1] needs a way to tell if a page is CMA or not. Add is_migrate_cma_page in a similar way to is_migrate_isolate_page. [1]http://article.gmane.org/gmane.linux.kernel.mm/155238 Signed-off-by: Laura Abbott <[email protected]> Signed-off-by: Kees Cook <[email protected]>
torvalds · Jul 26, 2016 · 7c15d9b · 7c15d9b
1 parent 523d939
commit 7c15d9b
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
@@ -68,8 +68,10 @@ extern char * const migratetype_names[MIGRATE_TYPES];
 
 #ifdef CONFIG_CMA
 #  define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA)
+#  define is_migrate_cma_page(_page) (get_pageblock_migratetype(_page) == MIGRATE_CMA)
 #else
 #  define is_migrate_cma(migratetype) false
+#  define is_migrate_cma_page(_page) false
 #endif
 
 #define for_each_migratetype_order(order, type) \