Merge remote-tracking branch 'linus/master' into staging/for_v3.5

* linus/master: (805 commits)
  tty: Fix LED error return
  openvswitch: checking wrong variable in queue_userspace_packet()
  bonding: Fix LACPDU rx_dropped commit.
  Linux 3.4-rc7
  ARM: EXYNOS: fix ctrlbit for exynos5_clk_pdma1
  ARM: EXYNOS: use s5p-timer for UniversalC210 board
  ARM / mach-shmobile: Invalidate caches when booting secondary cores
  ARM / mach-shmobile: sh73a0 SMP TWD boot regression fix
  ARM / mach-shmobile: r8a7779 SMP TWD boot regression fix
  ARM: mach-shmobile: convert ag5evm to use the generic MMC GPIO hotplug helper
  ARM: mach-shmobile: convert mackerel to use the generic MMC GPIO hotplug helper
  MAINTAINERS: Add myself as the cpufreq maintainer
  dm mpath: check if scsi_dh module already loaded before trying to load
  dm thin: correct module description
  dm thin: fix unprotected use of prepared_discards list
  dm thin: reinstate missing mempool_free in cell_release_singleton
  gpio/exynos: Fix compiler warnings when non-exynos machines are selected
  gpio: pch9: Use proper flow type handlers
  powerpc/irq: Fix another case of lazy IRQ state getting out of sync
  ks8851: Update link status during link change interrupt
  ...

Conflicts:
	drivers/media/common/tuners/xc5000.c
	drivers/media/common/tuners/xc5000.h
	drivers/usb/gadget/uvc_queue.c

1 files changed, 65 insertions, 24 deletions

diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c
index 7f36b38e060f..a7cad741df01 100644
--- a/net/core/drop_monitor.c
+++ b/net/core/drop_monitor.c
@@ -42,13 +42,14 @@ static void send_dm_alert(struct work_struct *unused);
  * netlink alerts
  */
 static int trace_state = TRACE_OFF;
-static DEFINE_SPINLOCK(trace_state_lock);
+static DEFINE_MUTEX(trace_state_mutex);
 
 struct per_cpu_dm_data {
         struct work_struct dm_alert_work;
-        struct sk_buff *skb;
+        struct sk_buff __rcu *skb;
         atomic_t dm_hit_count;
         struct timer_list send_timer;
+        int cpu;
 };
 
 struct dm_hw_stat_delta {
@@ -79,29 +80,53 @@ static void 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);
 
         al = sizeof(struct net_dm_alert_msg);
         al += dm_hit_limit * sizeof(struct net_dm_drop_point);
         al += sizeof(struct nlattr);
 
-        data->skb = genlmsg_new(al, GFP_KERNEL);
-        genlmsg_put(data->skb, 0, 0, &net_drop_monitor_family,
-                        0, NET_DM_CMD_ALERT);
-        nla = nla_reserve(data->skb, NLA_UNSPEC, sizeof(struct net_dm_alert_msg));
-        msg = nla_data(nla);
-        memset(msg, 0, al);
-        atomic_set(&data->dm_hit_count, dm_hit_limit);
+        skb = genlmsg_new(al, GFP_KERNEL);
+
+        if (skb) {
+                genlmsg_put(skb, 0, 0, &net_drop_monitor_family,
+                                0, NET_DM_CMD_ALERT);
+                nla = nla_reserve(skb, NLA_UNSPEC,
+                                  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);
+        }
+
 }
 
 static void send_dm_alert(struct work_struct *unused)
 {
         struct sk_buff *skb;
-        struct per_cpu_dm_data *data = &__get_cpu_var(dm_cpu_data);
+        struct per_cpu_dm_data *data = &get_cpu_var(dm_cpu_data);
+
+        WARN_ON_ONCE(data->cpu != smp_processor_id());
 
         /*
          * Grab the skb we're about to send
          */
-        skb = data->skb;
+        skb = rcu_dereference_protected(data->skb, 1);
 
         /*
          * Replace it with a new one
@@ -111,8 +136,10 @@ static void send_dm_alert(struct work_struct *unused)
         /*
          * Ship it!
          */
-        genlmsg_multicast(skb, 0, NET_DM_GRP_ALERT, GFP_KERNEL);
+        if (skb)
+                genlmsg_multicast(skb, 0, NET_DM_GRP_ALERT, GFP_KERNEL);
 
+        put_cpu_var(dm_cpu_data);
 }
 
 /*
@@ -123,9 +150,11 @@ static void send_dm_alert(struct work_struct *unused)
  */
 static void sched_send_work(unsigned long unused)
 {
-        struct per_cpu_dm_data *data =  &__get_cpu_var(dm_cpu_data);
+        struct per_cpu_dm_data *data =  &get_cpu_var(dm_cpu_data);
+
+        schedule_work_on(smp_processor_id(), &data->dm_alert_work);
 
-        schedule_work(&data->dm_alert_work);
+        put_cpu_var(dm_cpu_data);
 }
 
 static void trace_drop_common(struct sk_buff *skb, void *location)
@@ -134,8 +163,15 @@ static void trace_drop_common(struct sk_buff *skb, void *location)
         struct nlmsghdr *nlh;
         struct nlattr *nla;
         int i;
-        struct per_cpu_dm_data *data = &__get_cpu_var(dm_cpu_data);
+        struct sk_buff *dskb;
+        struct per_cpu_dm_data *data = &get_cpu_var(dm_cpu_data);
+
+
+        rcu_read_lock();
+        dskb = rcu_dereference(data->skb);
 
+        if (!dskb)
+                goto out;
 
         if (!atomic_add_unless(&data->dm_hit_count, -1, 0)) {
                 /*
@@ -144,12 +180,13 @@ static void trace_drop_common(struct sk_buff *skb, void *location)
                 goto out;
         }
 
-        nlh = (struct nlmsghdr *)data->skb->data;
+        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;
                 }
         }
@@ -157,7 +194,7 @@ static void trace_drop_common(struct sk_buff *skb, void *location)
         /*
          * We need to create a new entry
          */
-        __nla_reserve_nohdr(data->skb, sizeof(struct net_dm_drop_point));
+        __nla_reserve_nohdr(dskb, sizeof(struct net_dm_drop_point));
         nla->nla_len += NLA_ALIGN(sizeof(struct net_dm_drop_point));
         memcpy(msg->points[msg->entries].pc, &location, sizeof(void *));
         msg->points[msg->entries].count = 1;
@@ -169,6 +206,8 @@ static void trace_drop_common(struct sk_buff *skb, void *location)
         }
 
 out:
+        rcu_read_unlock();
+        put_cpu_var(dm_cpu_data);
         return;
 }
 
@@ -213,7 +252,7 @@ static int set_all_monitor_traces(int state)
         struct dm_hw_stat_delta *new_stat = NULL;
         struct dm_hw_stat_delta *temp;
 
-        spin_lock(&trace_state_lock);
+        mutex_lock(&trace_state_mutex);
 
         if (state == trace_state) {
                 rc = -EAGAIN;
@@ -252,7 +291,7 @@ static int set_all_monitor_traces(int state)
                 rc = -EINPROGRESS;
 
 out_unlock:
-        spin_unlock(&trace_state_lock);
+        mutex_unlock(&trace_state_mutex);
 
         return rc;
 }
@@ -295,12 +334,12 @@ static int dropmon_net_event(struct notifier_block *ev_block,
 
                 new_stat->dev = dev;
                 new_stat->last_rx = jiffies;
-                spin_lock(&trace_state_lock);
+                mutex_lock(&trace_state_mutex);
                 list_add_rcu(&new_stat->list, &hw_stats_list);
-                spin_unlock(&trace_state_lock);
+                mutex_unlock(&trace_state_mutex);
                 break;
         case NETDEV_UNREGISTER:
-                spin_lock(&trace_state_lock);
+                mutex_lock(&trace_state_mutex);
                 list_for_each_entry_safe(new_stat, tmp, &hw_stats_list, list) {
                         if (new_stat->dev == dev) {
                                 new_stat->dev = NULL;
@@ -311,7 +350,7 @@ static int dropmon_net_event(struct notifier_block *ev_block,
                                 }
                         }
                 }
-                spin_unlock(&trace_state_lock);
+                mutex_unlock(&trace_state_mutex);
                 break;
         }
 out:
@@ -367,13 +406,15 @@ static int __init init_net_drop_monitor(void)
 
         for_each_present_cpu(cpu) {
                 data = &per_cpu(dm_cpu_data, cpu);
-                reset_per_cpu_data(data);
+                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.function = sched_send_work;
+                reset_per_cpu_data(data);
         }
 
+
         goto out;
 
 out_unreg: