From: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Date: Tue, 13 Dec 2016 00:43:17 +0000 (-0800)
Subject: mm/filemap.c: add comment for confusing logic in page_cache_tree_insert()
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=c70b647d381cba1899c953b0016b7dc185892f90;p=linux-beck.git

mm/filemap.c: add comment for confusing logic in page_cache_tree_insert()

Unlike THP, hugetlb pages are represented by one entry in the
radix-tree.

[akpm@linux-foundation.org: tweak comment]
Link: http://lkml.kernel.org/r/20161110163640.126124-1-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/mm/filemap.c b/mm/filemap.c
index 50b52fe51937..caa779f8797f 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -169,7 +169,10 @@ static int page_cache_tree_insert(struct address_space *mapping,
 static void page_cache_tree_delete(struct address_space *mapping,
 				   struct page *page, void *shadow)
 {
-	int i, nr = PageHuge(page) ? 1 : hpage_nr_pages(page);
+	int i, nr;
+
+	/* hugetlb pages are represented by one entry in the radix tree */
+	nr = PageHuge(page) ? 1 : hpage_nr_pages(page);
 
 	VM_BUG_ON_PAGE(!PageLocked(page), page);
 	VM_BUG_ON_PAGE(PageTail(page), page);