linux-kernel - [patch 1/4] mm: page_alloc: remove order assumption from __free_pages

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Message-Id: <1323784711-1937-2-git-send-email-hannes@cmpxchg.org>
Date:	Tue, 13 Dec 2011 14:58:28 +0100
From:	Johannes Weiner <hannes@...xchg.org>
To:	Andrew Morton <akpm@...ux-foundation.org>,
	Uwe Kleine-König 
	<u.kleine-koenig@...gutronix.de>
Cc:	linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: [patch 1/4] mm: page_alloc: remove order assumption from __free_pages_bootmem()

Even though bootmem passes an order with the page to be freed,
__free_pages_bootmem() assumes that 1 << order is always BITS_PER_LONG
if non-zero.  While this happens to be true, it's not really robust.
Remove that assumption and use 1 << order instead.

Signed-off-by: Johannes Weiner <hannes@...xchg.org>
---
 mm/page_alloc.c |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2b8ba3a..4d5e91c 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -703,13 +703,14 @@ void __meminit __free_pages_bootmem(struct page *page, unsigned int order)
 		set_page_refcounted(page);
 		__free_page(page);
 	} else {
-		int loop;
+		unsigned int nr_pages = 1 << order;
+		unsigned int loop;
 
 		prefetchw(page);
-		for (loop = 0; loop < BITS_PER_LONG; loop++) {
+		for (loop = 0; loop < nr_pages; loop++) {
 			struct page *p = &page[loop];
 
-			if (loop + 1 < BITS_PER_LONG)
+			if (loop + 1 < nr_pages)
 				prefetchw(p + 1);
 			__ClearPageReserved(p);
 			set_page_count(p, 0);
-- 
1.7.7.3

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