From f10f6a1534401172248e2d16ff9a4e15397eabf5 Mon Sep 17 00:00:00 2001
From: David Rientjes <rientjes@google.com>
Date: Mon, 21 Sep 2009 17:04:31 -0700
Subject: [PATCH] --- yaml --- r: 164525 b: refs/heads/master c:
 4af5a2f770cc8575840ccb1514ec76ecb592985c h: refs/heads/master i:   164523:
 1fd235906fc7257cabcc72d55bea4fffd8ddc7b0 v: v3

---
 [refs]                           |  2 +-
 trunk/include/linux/flex_array.h |  1 +
 trunk/lib/flex_array.c           | 40 ++++++++++++++++++++++++++++++++
 3 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index 030124a29cd9..b48f5e8cc649 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 19da3dd157f8db6fe727ff268dab4791d55a6371
+refs/heads/master: 4af5a2f770cc8575840ccb1514ec76ecb592985c
diff --git a/trunk/include/linux/flex_array.h b/trunk/include/linux/flex_array.h
index 3887b21f883f..f12401e485fe 100644
--- a/trunk/include/linux/flex_array.h
+++ b/trunk/include/linux/flex_array.h
@@ -46,5 +46,6 @@ int flex_array_put(struct flex_array *fa, unsigned int element_nr, void *src,
 		gfp_t flags);
 int flex_array_clear(struct flex_array *fa, unsigned int element_nr);
 void *flex_array_get(struct flex_array *fa, unsigned int element_nr);
+int flex_array_shrink(struct flex_array *fa);
 
 #endif /* _FLEX_ARRAY_H */
diff --git a/trunk/lib/flex_array.c b/trunk/lib/flex_array.c
index e22d0e9776aa..1b03bb553410 100644
--- a/trunk/lib/flex_array.c
+++ b/trunk/lib/flex_array.c
@@ -291,3 +291,43 @@ void *flex_array_get(struct flex_array *fa, unsigned int element_nr)
 	}
 	return &part->elements[index_inside_part(fa, element_nr)];
 }
+
+static int part_is_free(struct flex_array_part *part)
+{
+	int i;
+
+	for (i = 0; i < sizeof(struct flex_array_part); i++)
+		if (part->elements[i] != FLEX_ARRAY_FREE)
+			return 0;
+	return 1;
+}
+
+/**
+ * flex_array_shrink - free unused second-level pages
+ *
+ * Frees all second-level pages that consist solely of unused
+ * elements.  Returns the number of pages freed.
+ *
+ * Locking must be provided by the caller.
+ */
+int flex_array_shrink(struct flex_array *fa)
+{
+	struct flex_array_part *part;
+	int max_part = nr_base_part_ptrs();
+	int part_nr;
+	int ret = 0;
+
+	if (elements_fit_in_base(fa))
+		return ret;
+	for (part_nr = 0; part_nr < max_part; part_nr++) {
+		part = fa->parts[part_nr];
+		if (!part)
+			continue;
+		if (part_is_free(part)) {
+			fa->parts[part_nr] = NULL;
+			kfree(part);
+			ret++;
+		}
+	}
+	return ret;
+}