mm: add zap_skip_check_mapping() helper

[sfrench/cifs-2.6.git] / include / linux / mm.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index c5b600d7f85bdd11c9b0b744e41893cacf94deae..6e29deb1e0d4b87e73c4749c9ab19dc4aa8f92fc 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1687,10 +1687,24 @@ extern void user_shm_unlock(size_t, struct ucounts *);
  * Parameter block passed down to zap_pte_range in exceptional cases.
  */
 struct zap_details {
-       struct address_space *check_mapping;    /* Check page->mapping if set */
+       struct address_space *zap_mapping;      /* Check page->mapping if set */
        struct page *single_page;               /* Locked page to be unmapped */
 };
 
+/*
+ * We set details->zap_mappings when we want to unmap shared but keep private
+ * pages. Return true if skip zapping this page, false otherwise.
+ */
+static inline bool
+zap_skip_check_mapping(struct zap_details *details, struct page *page)
+{
+       if (!details || !page)
+               return false;
+
+       return details->zap_mapping &&
+           (details->zap_mapping != page_rmapping(page));
+}
+
 struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
                             pte_t pte);
 struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr,