From ec84821507be44480e831d6f3d89df9e2b13728e Mon Sep 17 00:00:00 2001
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Date: Wed, 1 Apr 2020 21:04:57 -0700
Subject: [PATCH] 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.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20200318140253.6141-3-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
include/linux/pagemap.h | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index ccb14b6a16b54..5b0e6343229da 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -333,14 +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)
+/*
+ * 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);
--
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