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-rw-r--r--include/linux/pagemap.h13
1 files changed, 13 insertions, 0 deletions
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index bcf909d0de5f..2e8438a1216a 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -333,6 +333,19 @@ static inline struct page *grab_cache_page_nowait(struct address_space *mapping,
mapping_gfp_mask(mapping));
}
+static inline struct page *find_subpage(struct page *page, pgoff_t offset)
+{
+ unsigned long mask;
+
+ if (PageHuge(page))
+ return page;
+
+ VM_BUG_ON_PAGE(PageTail(page), page);
+
+ mask = (1UL << compound_order(page)) - 1;
+ return page + (offset & mask);
+}
+
struct page *find_get_entry(struct address_space *mapping, pgoff_t offset);
struct page *find_lock_entry(struct address_space *mapping, pgoff_t offset);
unsigned find_get_entries(struct address_space *mapping, pgoff_t start,