[034/155] include/linux/pagemap.h: rename arguments to find_subpage

Commit Message

Andrew Morton April 2, 2020, 4:04 a.m. UTC

From: "Matthew Wilcox (Oracle)" <[e-mail]>
Subject: include/linux/pagemap.h: rename arguments to find_subpage

This isn't just a random struct page, it's known to be a head page, and
calling it head makes the function better self-documenting.  The pgoff_t
is less confusing if it's named index instead of offset.  Also add a
couple of comments to explain why we're doing various things.

Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Matthew Wilcox (Oracle) <[e-mail]>
Reviewed-by: Christoph Hellwig <[e-mail]>
Acked-by: Kirill A. Shutemov <[e-mail]>
Acked-by: Pankaj Gupta <[e-mail]>
Cc: Aneesh Kumar K.V <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 include/linux/pagemap.h |   15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

Patch

--- a/include/linux/pagemap.h~mm-rename-arguments-to-find_subpage
+++ a/include/linux/pagemap.h
@@ -333,14 +333,19 @@  static inline struct page *grab_cache_pa
 			mapping_gfp_mask(mapping));
 }
 
-static inline struct page *find_subpage(struct page *page, pgoff_t offset)
+/*
+ * Given the page we found in the page cache, return the page corresponding
+ * to this index in the file
+ */
+static inline struct page *find_subpage(struct page *head, pgoff_t index)
 {
-	if (PageHuge(page))
-		return page;
+	/* HugeTLBfs wants the head page regardless */
+	if (PageHuge(head))
+		return head;
 
-	VM_BUG_ON_PAGE(PageTail(page), page);
+	VM_BUG_ON_PAGE(PageTail(head), head);
 
-	return page + (offset & (compound_nr(page) - 1));
+	return head + (index & (compound_nr(head) - 1));
 }
 
 struct page *find_get_entry(struct address_space *mapping, pgoff_t offset);