diff options
| -rw-r--r-- | net/core/drop_monitor.c | 102 |
1 files changed, 33 insertions, 69 deletions
diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c index ea5fb9fcc3f5..d23b6682f4e9 100644 --- a/net/core/drop_monitor.c +++ b/net/core/drop_monitor.c @@ -36,9 +36,6 @@ #define TRACE_ON 1 #define TRACE_OFF 0 -static void send_dm_alert(struct work_struct *unused); - - /* * Globals, our netlink socket pointer * and the work handle that will send up @@ -48,11 +45,10 @@ static int trace_state = TRACE_OFF; static DEFINE_MUTEX(trace_state_mutex); struct per_cpu_dm_data { - struct work_struct dm_alert_work; - struct sk_buff __rcu *skb; - atomic_t dm_hit_count; - struct timer_list send_timer; - int cpu; + spinlock_t lock; + struct sk_buff *skb; + struct work_struct dm_alert_work; + struct timer_list send_timer; }; struct dm_hw_stat_delta { @@ -78,13 +74,13 @@ static int dm_delay = 1; static unsigned long dm_hw_check_delta = 2*HZ; static LIST_HEAD(hw_stats_list); -static void reset_per_cpu_data(struct per_cpu_dm_data *data) +static struct sk_buff *reset_per_cpu_data(struct per_cpu_dm_data *data) { size_t al; struct net_dm_alert_msg *msg; struct nlattr *nla; struct sk_buff *skb; - struct sk_buff *oskb = rcu_dereference_protected(data->skb, 1); + unsigned long flags; al = sizeof(struct net_dm_alert_msg); al += dm_hit_limit * sizeof(struct net_dm_drop_point); @@ -99,65 +95,40 @@ static void reset_per_cpu_data(struct per_cpu_dm_data *data) sizeof(struct net_dm_alert_msg)); msg = nla_data(nla); memset(msg, 0, al); - } else - schedule_work_on(data->cpu, &data->dm_alert_work); - - /* - * Don't need to lock this, since we are guaranteed to only - * run this on a single cpu at a time. - * Note also that we only update data->skb if the old and new skb - * pointers don't match. This ensures that we don't continually call - * synchornize_rcu if we repeatedly fail to alloc a new netlink message. - */ - if (skb != oskb) { - rcu_assign_pointer(data->skb, skb); - - synchronize_rcu(); - - atomic_set(&data->dm_hit_count, dm_hit_limit); + } else { + mod_timer(&data->send_timer, jiffies + HZ / 10); } + spin_lock_irqsave(&data->lock, flags); + swap(data->skb, skb); + spin_unlock_irqrestore(&data->lock, flags); + + return skb; } -static void send_dm_alert(struct work_struct *unused) +static void send_dm_alert(struct work_struct *work) { struct sk_buff *skb; - struct per_cpu_dm_data *data = &get_cpu_var(dm_cpu_data); + struct per_cpu_dm_data *data; - WARN_ON_ONCE(data->cpu != smp_processor_id()); + data = container_of(work, struct per_cpu_dm_data, dm_alert_work); - /* - * Grab the skb we're about to send - */ - skb = rcu_dereference_protected(data->skb, 1); - - /* - * Replace it with a new one - */ - reset_per_cpu_data(data); + skb = reset_per_cpu_data(data); - /* - * Ship it! - */ if (skb) genlmsg_multicast(skb, 0, NET_DM_GRP_ALERT, GFP_KERNEL); - - put_cpu_var(dm_cpu_data); } /* * This is the timer function to delay the sending of an alert * in the event that more drops will arrive during the - * hysteresis period. Note that it operates under the timer interrupt - * so we don't need to disable preemption here + * hysteresis period. */ -static void sched_send_work(unsigned long unused) +static void sched_send_work(unsigned long _data) { - struct per_cpu_dm_data *data = &get_cpu_var(dm_cpu_data); - - schedule_work_on(smp_processor_id(), &data->dm_alert_work); + struct per_cpu_dm_data *data = (struct per_cpu_dm_data *)_data; - put_cpu_var(dm_cpu_data); + schedule_work(&data->dm_alert_work); } static void trace_drop_common(struct sk_buff *skb, void *location) @@ -167,33 +138,28 @@ static void trace_drop_common(struct sk_buff *skb, void *location) struct nlattr *nla; int i; struct sk_buff *dskb; - struct per_cpu_dm_data *data = &get_cpu_var(dm_cpu_data); - + struct per_cpu_dm_data *data; + unsigned long flags; - rcu_read_lock(); - dskb = rcu_dereference(data->skb); + local_irq_save(flags); + data = &__get_cpu_var(dm_cpu_data); + spin_lock(&data->lock); + dskb = data->skb; if (!dskb) goto out; - if (!atomic_add_unless(&data->dm_hit_count, -1, 0)) { - /* - * we're already at zero, discard this hit - */ - goto out; - } - nlh = (struct nlmsghdr *)dskb->data; nla = genlmsg_data(nlmsg_data(nlh)); msg = nla_data(nla); for (i = 0; i < msg->entries; i++) { if (!memcmp(&location, msg->points[i].pc, sizeof(void *))) { msg->points[i].count++; - atomic_inc(&data->dm_hit_count); goto out; } } - + if (msg->entries == dm_hit_limit) + goto out; /* * We need to create a new entry */ @@ -205,13 +171,11 @@ static void trace_drop_common(struct sk_buff *skb, void *location) if (!timer_pending(&data->send_timer)) { data->send_timer.expires = jiffies + dm_delay * HZ; - add_timer_on(&data->send_timer, smp_processor_id()); + add_timer(&data->send_timer); } out: - rcu_read_unlock(); - put_cpu_var(dm_cpu_data); - return; + spin_unlock_irqrestore(&data->lock, flags); } static void trace_kfree_skb_hit(void *ignore, struct sk_buff *skb, void *location) @@ -418,11 +382,11 @@ static int __init init_net_drop_monitor(void) for_each_possible_cpu(cpu) { data = &per_cpu(dm_cpu_data, cpu); - data->cpu = cpu; INIT_WORK(&data->dm_alert_work, send_dm_alert); init_timer(&data->send_timer); - data->send_timer.data = cpu; + data->send_timer.data = (unsigned long)data; data->send_timer.function = sched_send_work; + spin_lock_init(&data->lock); reset_per_cpu_data(data); } |