[Devel] [PATCH rh7 1/6] memcg: add mem_cgroup_get/put helpers

[Vladimir Davydov]

Equivalent to css_get/put(mem_cgroup_css(memcg)). Currently, only used
by af_packet.c, but will also be used by the following patches.

Signed-off-by: Vladimir Davydov <vdavydov at parallels.com>
---
 include/linux/memcontrol.h | 18 ++++++++++++++++++
 net/packet/af_packet.c     |  4 ++--
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index ac3f16f0ee28..548a82cde972 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -139,6 +139,16 @@ static inline bool mem_cgroup_disabled(void)
 	return false;
 }
 
+static inline void mem_cgroup_get(struct mem_cgroup *memcg)
+{
+	css_get(mem_cgroup_css(memcg));
+}
+
+static inline void mem_cgroup_put(struct mem_cgroup *memcg)
+{
+	css_put(mem_cgroup_css(memcg));
+}
+
 void __mem_cgroup_begin_update_page_stat(struct page *page, bool *locked,
 					 unsigned long *flags);
 
@@ -321,6 +331,14 @@ static inline bool mem_cgroup_disabled(void)
 	return true;
 }
 
+static inline void mem_cgroup_get(struct mem_cgroup *memcg)
+{
+}
+
+static inline void mem_cgroup_put(struct mem_cgroup *memcg)
+{
+}
+
 static inline int
 mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec)
 {
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index ee9d56b48823..0bc235e6a62a 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -2524,7 +2524,7 @@ static struct cg_proto *packet_sk_charge(void)
 		goto out;
 
 out_put_cg:
-	css_put(mem_cgroup_css(psc->memcg));
+	mem_cgroup_put(psc->memcg);
 out_free_psc:
 	kfree(psc);
 	psc = NULL;
@@ -2545,7 +2545,7 @@ static void packet_sk_uncharge(struct cg_proto *cg)
 
 	if (psc) {
 		memcg_uncharge_kmem(psc->memcg, psc->amt);
-		css_put(mem_cgroup_css(psc->memcg));
+		mem_cgroup_put(psc->memcg);
 		kfree(psc);
 	}
 }
-- 
2.1.4