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-rw-r--r--mm/util.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/mm/util.c b/mm/util.c
index 3704bf1bef94..16a73195a37b 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -5,6 +5,7 @@
#include <linux/err.h>
#include <linux/sched.h>
#include <linux/security.h>
+#include <linux/swap.h>
#include <asm/uaccess.h>
#include "internal.h"
@@ -382,6 +383,21 @@ unsigned long vm_mmap(struct file *file, unsigned long addr,
}
EXPORT_SYMBOL(vm_mmap);
+struct address_space *page_mapping(struct page *page)
+{
+ struct address_space *mapping = page->mapping;
+
+ VM_BUG_ON(PageSlab(page));
+#ifdef CONFIG_SWAP
+ if (unlikely(PageSwapCache(page)))
+ mapping = &swapper_space;
+ else
+#endif
+ if ((unsigned long)mapping & PAGE_MAPPING_ANON)
+ mapping = NULL;
+ return mapping;
+}
+
/* Tracepoints definitions. */
EXPORT_TRACEPOINT_SYMBOL(kmalloc);
EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);