netfilter: x_tables: dont block BH while reading counters
[linux-3.10.git] / net / ipv6 / netfilter / ip6_tables.c
index 4555823..7d227c6 100644 (file)
@@ -897,42 +897,25 @@ get_counters(const struct xt_table_info *t,
        struct ip6t_entry *iter;
        unsigned int cpu;
        unsigned int i;
-       unsigned int curcpu = get_cpu();
-
-       /* Instead of clearing (by a previous call to memset())
-        * the counters and using adds, we set the counters
-        * with data used by 'current' CPU
-        *
-        * Bottom half has to be disabled to prevent deadlock
-        * if new softirq were to run and call ipt_do_table
-        */
-       local_bh_disable();
-       i = 0;
-       xt_entry_foreach(iter, t->entries[curcpu], t->size) {
-               SET_COUNTER(counters[i], iter->counters.bcnt,
-                           iter->counters.pcnt);
-               ++i;
-       }
-       local_bh_enable();
-       /* Processing counters from other cpus, we can let bottom half enabled,
-        * (preemption is disabled)
-        */
 
        for_each_possible_cpu(cpu) {
-               if (cpu == curcpu)
-                       continue;
+               seqlock_t *lock = &per_cpu(xt_info_locks, cpu).lock;
+
                i = 0;
-               local_bh_disable();
-               xt_info_wrlock(cpu);
                xt_entry_foreach(iter, t->entries[cpu], t->size) {
-                       ADD_COUNTER(counters[i], iter->counters.bcnt,
-                                   iter->counters.pcnt);
+                       u64 bcnt, pcnt;
+                       unsigned int start;
+
+                       do {
+                               start = read_seqbegin(lock);
+                               bcnt = iter->counters.bcnt;
+                               pcnt = iter->counters.pcnt;
+                       } while (read_seqretry(lock, start));
+
+                       ADD_COUNTER(counters[i], bcnt, pcnt);
                        ++i;
                }
-               xt_info_wrunlock(cpu);
-               local_bh_enable();
        }
-       put_cpu();
 }
 
 static struct xt_counters *alloc_counters(const struct xt_table *table)
@@ -945,7 +928,7 @@ static struct xt_counters *alloc_counters(const struct xt_table *table)
           (other than comefrom, which userspace doesn't care
           about). */
        countersize = sizeof(struct xt_counters) * private->number;
-       counters = vmalloc(countersize);
+       counters = vzalloc(countersize);
 
        if (counters == NULL)
                return ERR_PTR(-ENOMEM);
@@ -1216,7 +1199,7 @@ __do_replace(struct net *net, const char *name, unsigned int valid_hooks,
        struct ip6t_entry *iter;
 
        ret = 0;
-       counters = vmalloc(num_counters * sizeof(struct xt_counters));
+       counters = vzalloc(num_counters * sizeof(struct xt_counters));
        if (!counters) {
                ret = -ENOMEM;
                goto out;