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authorZhenzhong Duan <zhenzhong.duan@oracle.com>2012-09-21 16:40:30 +0800
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2012-09-21 10:37:45 -0400
commita00bb1e9fc0925c0061e9d844523a3a47a7e2f7f (patch)
treee4a276b1d44e5b34765377698260f9f857bff85a /mm/frontswap.c
parent15773b68fc5854e8890a8e251c568d583a540e4c (diff)
downloadlinux-a00bb1e9fc0925c0061e9d844523a3a47a7e2f7f.tar.gz
mm: frontswap: fix a wrong if condition in frontswap_shrink
pages_to_unuse is set to 0 to unuse all frontswap pages
But that doesn't happen since a wrong condition in frontswap_shrink
cancel it.

-v2: Add comment to explain return value of __frontswap_shrink,
as suggested by Dan Carpenter, thanks

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'mm/frontswap.c')
-rw-r--r--mm/frontswap.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/mm/frontswap.c b/mm/frontswap.c
index 89dc399d3328..0547a35f798b 100644
--- a/mm/frontswap.c
+++ b/mm/frontswap.c
@@ -263,6 +263,11 @@ static int __frontswap_unuse_pages(unsigned long total, unsigned long *unused,
 	return ret;
 }
 
+/*
+ * Used to check if it's necessory and feasible to unuse pages.
+ * Return 1 when nothing to do, 0 when need to shink pages,
+ * error code when there is an error.
+ */
 static int __frontswap_shrink(unsigned long target_pages,
 				unsigned long *pages_to_unuse,
 				int *type)
@@ -275,7 +280,7 @@ static int __frontswap_shrink(unsigned long target_pages,
 	if (total_pages <= target_pages) {
 		/* Nothing to do */
 		*pages_to_unuse = 0;
-		return 0;
+		return 1;
 	}
 	total_pages_to_unuse = total_pages - target_pages;
 	return __frontswap_unuse_pages(total_pages_to_unuse, pages_to_unuse, type);
@@ -302,7 +307,7 @@ void frontswap_shrink(unsigned long target_pages)
 	spin_lock(&swap_lock);
 	ret = __frontswap_shrink(target_pages, &pages_to_unuse, &type);
 	spin_unlock(&swap_lock);
-	if (ret == 0 && pages_to_unuse)
+	if (ret == 0)
 		try_to_unuse(type, true, pages_to_unuse);
 	return;
 }