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net/virtio-net: Convert to hotplug state machine

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Install the callbacks via the state machine.

The driver supports multiple instances and therefore the new
cpuhp_state_add_instance_nocalls() infrastrucure is used. The driver
currently uses get_online_cpus() to avoid missing a CPU hotplug event while
invoking virtnet_set_affinity(). This could be avoided by using
cpuhp_state_add_instance() variant which holds the hotplug lock and invokes
callback during registration. This is more or less a 1:1 conversion of the
current code.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: netdev@vger.kernel.org
Cc: Will Deacon <will.deacon@arm.com>
Cc: virtualization@lists.linux-foundation.org
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/1471024183-12666-7-git-send-email-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Sebastian Andrzej Siewior 2016-08-12 19:49:43 +02:00 committed by Thomas Gleixner
parent 8df038725a
commit 8017c27919
2 changed files with 87 additions and 24 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

108
drivers/net/virtio_net.c
View file

@ -138,8 +138,9 @@ struct virtnet_info {
/* Does the affinity hint is set for virtqueues? */
bool affinity_hint_set;
/* CPU hot plug notifier */
struct notifier_block nb;
/* CPU hotplug instances for online & dead */
struct hlist_node node;
struct hlist_node node_dead;
/* Control VQ buffers: protected by the rtnl lock */
struct virtio_net_ctrl_hdr ctrl_hdr;
@ -1237,25 +1238,53 @@ static void virtnet_set_affinity(struct virtnet_info *vi)
vi->affinity_hint_set = true;
}
static int virtnet_cpu_callback(struct notifier_block *nfb,
unsigned long action, void *hcpu)
static int virtnet_cpu_online(unsigned int cpu, struct hlist_node *node)
{
struct virtnet_info *vi = container_of(nfb, struct virtnet_info, nb);
switch(action & ~CPU_TASKS_FROZEN) {
case CPU_ONLINE:
case CPU_DOWN_FAILED:
case CPU_DEAD:
struct virtnet_info *vi = hlist_entry_safe(node, struct virtnet_info,
node);
virtnet_set_affinity(vi);
break;
case CPU_DOWN_PREPARE:
virtnet_clean_affinity(vi, (long)hcpu);
break;
default:
break;
return 0;
}
return NOTIFY_OK;
static int virtnet_cpu_dead(unsigned int cpu, struct hlist_node *node)
{
struct virtnet_info *vi = hlist_entry_safe(node, struct virtnet_info,
node_dead);
virtnet_set_affinity(vi);
return 0;
}
static int virtnet_cpu_down_prep(unsigned int cpu, struct hlist_node *node)
{
struct virtnet_info *vi = hlist_entry_safe(node, struct virtnet_info,
node);
virtnet_clean_affinity(vi, cpu);
return 0;
}
static enum cpuhp_state virtionet_online;
static int virtnet_cpu_notif_add(struct virtnet_info *vi)
{
int ret;
ret = cpuhp_state_add_instance_nocalls(virtionet_online, &vi->node);
if (ret)
return ret;
ret = cpuhp_state_add_instance_nocalls(CPUHP_VIRT_NET_DEAD,
&vi->node_dead);
if (!ret)
return ret;
cpuhp_state_remove_instance_nocalls(virtionet_online, &vi->node);
return ret;
}
static void virtnet_cpu_notif_remove(struct virtnet_info *vi)
{
cpuhp_state_remove_instance_nocalls(virtionet_online, &vi->node);
cpuhp_state_remove_instance_nocalls(CPUHP_VIRT_NET_DEAD,
&vi->node_dead);
}
static void virtnet_get_ringparam(struct net_device *dev,
@ -1879,8 +1908,7 @@ static int virtnet_probe(struct virtio_device *vdev)
virtio_device_ready(vdev);
vi->nb.notifier_call = &virtnet_cpu_callback;
err = register_hotcpu_notifier(&vi->nb);
err = virtnet_cpu_notif_add(vi);
if (err) {
pr_debug("virtio_net: registering cpu notifier failed\n");
goto free_unregister_netdev;
@ -1934,7 +1962,7 @@ static void virtnet_remove(struct virtio_device *vdev)
{
struct virtnet_info *vi = vdev->priv;
unregister_hotcpu_notifier(&vi->nb);
virtnet_cpu_notif_remove(vi);
/* Make sure no work handler is accessing the device. */
flush_work(&vi->config_work);
@ -1953,7 +1981,7 @@ static int virtnet_freeze(struct virtio_device *vdev)
struct virtnet_info *vi = vdev->priv;
int i;
unregister_hotcpu_notifier(&vi->nb);
virtnet_cpu_notif_remove(vi);
/* Make sure no work handler is accessing the device */
flush_work(&vi->config_work);
@ -1997,7 +2025,7 @@ static int virtnet_restore(struct virtio_device *vdev)
virtnet_set_queues(vi, vi->curr_queue_pairs);
rtnl_unlock();
err = register_hotcpu_notifier(&vi->nb);
err = virtnet_cpu_notif_add(vi);
if (err)
return err;
@ -2039,7 +2067,41 @@ static struct virtio_driver virtio_net_driver = {
#endif
};
module_virtio_driver(virtio_net_driver);
static __init int virtio_net_driver_init(void)
{
int ret;
ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "AP_VIRT_NET_ONLINE",
virtnet_cpu_online,
virtnet_cpu_down_prep);
if (ret < 0)
goto out;
virtionet_online = ret;
ret = cpuhp_setup_state_multi(CPUHP_VIRT_NET_DEAD, "VIRT_NET_DEAD",
NULL, virtnet_cpu_dead);
if (ret)
goto err_dead;
ret = register_virtio_driver(&virtio_net_driver);
if (ret)
goto err_virtio;
return 0;
err_virtio:
cpuhp_remove_multi_state(CPUHP_VIRT_NET_DEAD);
err_dead:
cpuhp_remove_multi_state(virtionet_online);
out:
return ret;
}
module_init(virtio_net_driver_init);
static __exit void virtio_net_driver_exit(void)
{
cpuhp_remove_multi_state(CPUHP_VIRT_NET_DEAD);
cpuhp_remove_multi_state(virtionet_online);
unregister_virtio_driver(&virtio_net_driver);
}
module_exit(virtio_net_driver_exit);
MODULE_DEVICE_TABLE(virtio, id_table);
MODULE_DESCRIPTION("Virtio network driver");

1
include/linux/cpuhotplug.h
View file

@ -14,6 +14,7 @@ enum cpuhp_state {
CPUHP_PERF_SUPERH,
CPUHP_X86_HPET_DEAD,
CPUHP_X86_APB_DEAD,
CPUHP_VIRT_NET_DEAD,
CPUHP_WORKQUEUE_PREP,
CPUHP_POWER_NUMA_PREPARE,
CPUHP_HRTIMERS_PREPARE,