[tip:smp/hotplug] net/flowcache: Convert to hotplug state machine

From: tip-bot for Sebastian Andrzej Siewior
Date: Wed Nov 09 2016 - 17:56:35 EST


Commit-ID: a4fc1bfc42062e8bc7b2271a90d17403b096ce5d
Gitweb: http://git.kernel.org/tip/a4fc1bfc42062e8bc7b2271a90d17403b096ce5d
Author: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
AuthorDate: Thu, 3 Nov 2016 15:50:05 +0100
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Wed, 9 Nov 2016 23:45:28 +0100

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@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Cc: netdev@xxxxxxxxxxxxxxx
Cc: rt@xxxxxxxxxxxxx
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20161103145021.28528-10-bigeasy@xxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

---
include/linux/cpuhotplug.h | 1 +
include/net/flow.h | 1 +
include/net/flowcache.h | 2 +-
net/core/flow.c | 60 ++++++++++++++++++++--------------------------
net/xfrm/xfrm_policy.c | 1 +
5 files changed, 30 insertions(+), 35 deletions(-)

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 394eb7e..86b940f 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -56,6 +56,7 @@ enum cpuhp_state {
CPUHP_ARM_SHMOBILE_SCU_PREPARE,
CPUHP_SH_SH3X_PREPARE,
CPUHP_BLK_MQ_PREPARE,
+ CPUHP_NET_FLOW_PREPARE,
CPUHP_TIMERS_DEAD,
CPUHP_NOTF_ERR_INJ_PREPARE,
CPUHP_MIPS_SOC_PREPARE,
diff --git a/include/net/flow.h b/include/net/flow.h
index 035aa77..2e386bd 100644
--- a/include/net/flow.h
+++ b/include/net/flow.h
@@ -239,6 +239,7 @@ struct flow_cache_object *flow_cache_lookup(struct net *net,
void *ctx);
int flow_cache_init(struct net *net);
void flow_cache_fini(struct net *net);
+void flow_cache_hp_init(void);

void flow_cache_flush(struct net *net);
void flow_cache_flush_deferred(struct net *net);
diff --git a/include/net/flowcache.h b/include/net/flowcache.h
index c8f665e..9caf3bf 100644
--- a/include/net/flowcache.h
+++ b/include/net/flowcache.h
@@ -17,7 +17,7 @@ struct flow_cache_percpu {
struct flow_cache {
u32 hash_shift;
struct flow_cache_percpu __percpu *percpu;
- struct notifier_block hotcpu_notifier;
+ struct hlist_node node;
int low_watermark;
int high_watermark;
struct timer_list rnd_timer;
diff --git a/net/core/flow.c b/net/core/flow.c
index 3937b1b..841fd7f 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);
+}
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index fd69866..4a8eff1 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -3111,6 +3111,7 @@ static struct pernet_operations __net_initdata xfrm_net_ops = {

void __init xfrm_init(void)
{
+ flow_cache_hp_init();
register_pernet_subsys(&xfrm_net_ops);
seqcount_init(&xfrm_policy_hash_generation);
xfrm_input_init();