lkml.org 
[lkml]   [2021]   [Mar]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v4 09/25] mm: Add folio_index, folio_page and folio_contains
Date
folio_index() is the equivalent of page_index() for folios.  folio_page()
finds the page in a folio for a page cache index. folio_contains()
tells you whether a folio contains a particular page cache index.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
include/linux/pagemap.h | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index f07c03da83f6..5094b50f7680 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -447,6 +447,29 @@ static inline bool thp_contains(struct page *head, pgoff_t index)
return page_index(head) == (index & ~(thp_nr_pages(head) - 1UL));
}

+static inline pgoff_t folio_index(struct folio *folio)
+{
+ if (unlikely(FolioSwapCache(folio)))
+ return __page_file_index(&folio->page);
+ return folio->page.index;
+}
+
+static inline struct page *folio_page(struct folio *folio, pgoff_t index)
+{
+ index -= folio_index(folio);
+ VM_BUG_ON_FOLIO(index >= folio_nr_pages(folio), folio);
+ return &folio->page + index;
+}
+
+/* Does this folio contain this index? */
+static inline bool folio_contains(struct folio *folio, pgoff_t index)
+{
+ /* HugeTLBfs indexes the page cache in units of hpage_size */
+ if (PageHuge(&folio->page))
+ return folio->page.index == index;
+ return index - folio_index(folio) < folio_nr_pages(folio);
+}
+
/*
* Given the page we found in the page cache, return the page corresponding
* to this index in the file
--
2.30.0
\
 
 \ /
  Last update: 2021-03-05 05:22    [W:0.685 / U:0.344 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site