memcg: do not allow to disable tcp accounting after limit is set

[karo-tx-linux.git] / net / ipv4 / tcp_memcontrol.c

diff --git a/net/ipv4/tcp_memcontrol.c b/net/ipv4/tcp_memcontrol.c
index 2379c1b4efb24505dd9b62316912cdfcdd371001..d07579ada0014952394aa0a52c678757cff038a8 100644 (file)
--- a/net/ipv4/tcp_memcontrol.c
+++ b/net/ipv4/tcp_memcontrol.c
@@ -48,7 +48,7 @@ void tcp_destroy_cgroup(struct mem_cgroup *memcg)
 
        percpu_counter_destroy(&cg_proto->sockets_allocated);
 
-       if (test_bit(MEMCG_SOCK_ACTIVATED, &cg_proto->flags))
+       if (cg_proto->active)
                static_key_slow_dec(&memcg_socket_limit_enabled);
 
 }
@@ -72,11 +72,9 @@ static int tcp_update_limit(struct mem_cgroup *memcg, unsigned long nr_pages)
                cg_proto->sysctl_mem[i] = min_t(long, nr_pages,
                                                sysctl_tcp_mem[i]);
 
-       if (nr_pages == PAGE_COUNTER_MAX)
-               clear_bit(MEMCG_SOCK_ACTIVE, &cg_proto->flags);
-       else {
+       if (!cg_proto->active) {
                /*
-                * The active bit needs to be written after the static_key
+                * The active flag needs to be written after the static_key
                 * update. This is what guarantees that the socket activation
                 * function is the last one to run. See sock_update_memcg() for
                 * details, and note that we don't mark any socket as belonging
@@ -90,14 +88,9 @@ static int tcp_update_limit(struct mem_cgroup *memcg, unsigned long nr_pages)
                 * We never race with the readers in sock_update_memcg(),
                 * because when this value change, the code to process it is not
                 * patched in yet.
-                *
-                * The activated bit is used to guarantee that no two writers
-                * will do the update in the same memcg. Without that, we can't
-                * properly shutdown the static key.
                 */
-               if (!test_and_set_bit(MEMCG_SOCK_ACTIVATED, &cg_proto->flags))
-                       static_key_slow_inc(&memcg_socket_limit_enabled);
-               set_bit(MEMCG_SOCK_ACTIVE, &cg_proto->flags);
+               static_key_slow_inc(&memcg_socket_limit_enabled);
+               cg_proto->active = true;
        }
 
        return 0;