diff options
Diffstat (limited to 'include/linux/pagemap.h')
| -rw-r--r-- | include/linux/pagemap.h | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index df214a4b886d..4d08b6c33557 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -394,10 +394,21 @@ static inline struct page *read_mapping_page(struct address_space *mapping, */ static inline pgoff_t page_to_pgoff(struct page *page) { + pgoff_t pgoff; + if (unlikely(PageHeadHuge(page))) return page->index << compound_order(page); - else + + if (likely(!PageTransTail(page))) return page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); + + /* + * We don't initialize ->index for tail pages: calculate based on + * head page + */ + pgoff = compound_head(page)->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); + pgoff += page - compound_head(page); + return pgoff; } /* |