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>
diff --git a/mm/frontswap.c b/mm/frontswap.c
index 89dc399..0547a35 100644
--- a/mm/frontswap.c
+++ b/mm/frontswap.c
@@ -263,6 +263,11 @@
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 @@
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 @@
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;
}