net/flowcache: Convert to hotplug state machine

Install the callbacks via the state machine. Use multi state support to avoid
custom list handling for the multiple instances.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: netdev@vger.kernel.org
Cc: rt@linutronix.de
Cc: "David S. Miller" <davem@davemloft.net>
Link: http://lkml.kernel.org/r/20161103145021.28528-10-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 26 insertions, 34 deletions

diff --git a/net/core/flow.c b/net/core/flow.c
index 3937b1b68d5b..841fd7f87b30 100644
--- a/net/core/flow.c
+++ b/net/core/flow.c
@@ -419,28 +419,20 @@ static int flow_cache_cpu_prepare(struct flow_cache *fc, int cpu)
         return 0;
 }
 
-static int flow_cache_cpu(struct notifier_block *nfb,
-                          unsigned long action,
-                          void *hcpu)
+static int flow_cache_cpu_up_prep(unsigned int cpu, struct hlist_node *node)
 {
-        struct flow_cache *fc = container_of(nfb, struct flow_cache,
-                                                hotcpu_notifier);
-        int res, cpu = (unsigned long) hcpu;
+        struct flow_cache *fc = hlist_entry_safe(node, struct flow_cache, node);
+
+        return flow_cache_cpu_prepare(fc, cpu);
+}
+
+static int flow_cache_cpu_dead(unsigned int cpu, struct hlist_node *node)
+{
+        struct flow_cache *fc = hlist_entry_safe(node, struct flow_cache, node);
         struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, cpu);
 
-        switch (action) {
-        case CPU_UP_PREPARE:
-        case CPU_UP_PREPARE_FROZEN:
-                res = flow_cache_cpu_prepare(fc, cpu);
-                if (res)
-                        return notifier_from_errno(res);
-                break;
-        case CPU_DEAD:
-        case CPU_DEAD_FROZEN:
-                __flow_cache_shrink(fc, fcp, 0);
-                break;
-        }
-        return NOTIFY_OK;
+        __flow_cache_shrink(fc, fcp, 0);
+        return 0;
 }
 
 int flow_cache_init(struct net *net)
@@ -467,18 +459,8 @@ int flow_cache_init(struct net *net)
         if (!fc->percpu)
                 return -ENOMEM;
 
-        cpu_notifier_register_begin();
-
-        for_each_online_cpu(i) {
-                if (flow_cache_cpu_prepare(fc, i))
-                        goto err;
-        }
-        fc->hotcpu_notifier = (struct notifier_block){
-                .notifier_call = flow_cache_cpu,
-        };
-        __register_hotcpu_notifier(&fc->hotcpu_notifier);
-
-        cpu_notifier_register_done();
+        if (cpuhp_state_add_instance(CPUHP_NET_FLOW_PREPARE, &fc->node))
+                goto err;
 
         setup_timer(&fc->rnd_timer, flow_cache_new_hashrnd,
                     (unsigned long) fc);
@@ -494,8 +476,6 @@ err:
                 fcp->hash_table = NULL;
         }
 
-        cpu_notifier_register_done();
-
         free_percpu(fc->percpu);
         fc->percpu = NULL;
 
@@ -509,7 +489,8 @@ void flow_cache_fini(struct net *net)
         struct flow_cache *fc = &net->xfrm.flow_cache_global;
 
         del_timer_sync(&fc->rnd_timer);
-        unregister_hotcpu_notifier(&fc->hotcpu_notifier);
+
+        cpuhp_state_remove_instance_nocalls(CPUHP_NET_FLOW_PREPARE, &fc->node);
 
         for_each_possible_cpu(i) {
                 struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, i);
@@ -521,3 +502,14 @@ void flow_cache_fini(struct net *net)
         fc->percpu = NULL;
 }
 EXPORT_SYMBOL(flow_cache_fini);
+
+void __init flow_cache_hp_init(void)
+{
+        int ret;
+
+        ret = cpuhp_setup_state_multi(CPUHP_NET_FLOW_PREPARE,
+                                      "net/flow:prepare",
+                                      flow_cache_cpu_up_prep,
+                                      flow_cache_cpu_dead);
+        WARN_ON(ret < 0);
+}