From: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Date: Tue, 7 Apr 2015 23:44:26 +0000 (+1000)
Subject: page-flags: define PG_uptodate behavior on compound pages
X-Git-Tag: KARO-TXA5-2015-06-26~18^2~317
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=9802775f2a29851ad38bfb1d782f0f6eb30da21b;p=karo-tx-linux.git

page-flags: define PG_uptodate behavior on compound pages

We use PG_uptodate on head pages on transparent huge page.
Let's use NO_TAIL.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 0b6921d2f2f3..55a69c40e4ae 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -408,8 +408,9 @@ u64 stable_page_flags(struct page *page);
 
 static inline int PageUptodate(struct page *page)
 {
-	int ret = test_bit(PG_uptodate, &(page)->flags);
-
+	int ret;
+	page = compound_head(page);
+	ret = test_bit(PG_uptodate, &(page)->flags);
 	/*
 	 * Must ensure that the data we read out of the page is loaded
 	 * _after_ we've loaded page->flags to check for PageUptodate.
@@ -426,12 +427,14 @@ static inline int PageUptodate(struct page *page)
 
 static inline void __SetPageUptodate(struct page *page)
 {
+	VM_BUG_ON_PAGE(PageTail(page), page);
 	smp_wmb();
 	__set_bit(PG_uptodate, &page->flags);
 }
 
 static inline void SetPageUptodate(struct page *page)
 {
+	VM_BUG_ON_PAGE(PageTail(page), page);
 	/*
 	 * Memory barrier must be issued before setting the PG_uptodate bit,
 	 * so that all previous stores issued in order to bring the page
@@ -441,7 +444,7 @@ static inline void SetPageUptodate(struct page *page)
 	set_bit(PG_uptodate, &page->flags);
 }
 
-CLEARPAGEFLAG(Uptodate, uptodate, ANY)
+CLEARPAGEFLAG(Uptodate, uptodate, NO_TAIL)
 
 int test_clear_page_writeback(struct page *page);
 int __test_set_page_writeback(struct page *page, bool keep_write);