openvswitch: fix a possible deadlock and lockdep warning

[~andy/linux] / net / openvswitch / flow.c

diff --git a/net/openvswitch/flow.c b/net/openvswitch/flow.c
index d71e60fa28cb7b4f634a37c84e8b575c9eedecce..2998989e76db0a7ccb8e25ef11aa393180956593 100644 (file)
--- a/net/openvswitch/flow.c
+++ b/net/openvswitch/flow.c
@@ -92,7 +92,7 @@ static void stats_read(struct flow_stats *stats,
                       unsigned long *used, __be16 *tcp_flags)
 {
        spin_lock(&stats->lock);
-       if (time_after(stats->used, *used))
+       if (!*used || time_after(stats->used, *used))
                *used = stats->used;
        *tcp_flags |= stats->tcp_flags;
        ovs_stats->n_packets += stats->packet_count;
@@ -103,30 +103,24 @@ static void stats_read(struct flow_stats *stats,
 void ovs_flow_stats_get(struct sw_flow *flow, struct ovs_flow_stats *ovs_stats,
                        unsigned long *used, __be16 *tcp_flags)
 {
-       int cpu, cur_cpu;
+       int cpu;
 
        *used = 0;
        *tcp_flags = 0;
        memset(ovs_stats, 0, sizeof(*ovs_stats));
 
+       local_bh_disable();
        if (!flow->stats.is_percpu) {
                stats_read(flow->stats.stat, ovs_stats, used, tcp_flags);
        } else {
-               cur_cpu = get_cpu();
                for_each_possible_cpu(cpu) {
                        struct flow_stats *stats;
 
-                       if (cpu == cur_cpu)
-                               local_bh_disable();
-
                        stats = per_cpu_ptr(flow->stats.cpu_stats, cpu);
                        stats_read(stats, ovs_stats, used, tcp_flags);
-
-                       if (cpu == cur_cpu)
-                               local_bh_enable();
                }
-               put_cpu();
        }
+       local_bh_enable();
 }
 
 static void stats_reset(struct flow_stats *stats)
@@ -141,25 +135,17 @@ static void stats_reset(struct flow_stats *stats)
 
 void ovs_flow_stats_clear(struct sw_flow *flow)
 {
-       int cpu, cur_cpu;
+       int cpu;
 
+       local_bh_disable();
        if (!flow->stats.is_percpu) {
                stats_reset(flow->stats.stat);
        } else {
-               cur_cpu = get_cpu();
-
                for_each_possible_cpu(cpu) {
-
-                       if (cpu == cur_cpu)
-                               local_bh_disable();
-
                        stats_reset(per_cpu_ptr(flow->stats.cpu_stats, cpu));
-
-                       if (cpu == cur_cpu)
-                               local_bh_enable();
                }
-               put_cpu();
        }
+       local_bh_enable();
 }
 
 static int check_header(struct sk_buff *skb, int len)