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Diffstat (limited to 'include/linux/mm.h')
-rw-r--r--include/linux/mm.h29
1 files changed, 17 insertions, 12 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h
index d6777060449f..368600628d14 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -407,20 +407,25 @@ static inline void compound_unlock_irqrestore(struct page *page,
#endif
}
+static inline struct page *compound_head_by_tail(struct page *tail)
+{
+ struct page *head = tail->first_page;
+
+ /*
+ * page->first_page may be a dangling pointer to an old
+ * compound page, so recheck that it is still a tail
+ * page before returning.
+ */
+ smp_rmb();
+ if (likely(PageTail(tail)))
+ return head;
+ return tail;
+}
+
static inline struct page *compound_head(struct page *page)
{
- if (unlikely(PageTail(page))) {
- struct page *head = page->first_page;
-
- /*
- * page->first_page may be a dangling pointer to an old
- * compound page, so recheck that it is still a tail
- * page before returning.
- */
- smp_rmb();
- if (likely(PageTail(page)))
- return head;
- }
+ if (unlikely(PageTail(page)))
+ return compound_head_by_tail(page);
return page;
}