Commit-ID: 8017c279196ab29174bafc104ac4ebbd42c7ca7f Gitweb: http://git.kernel.org/tip/8017c279196ab29174bafc104ac4ebbd42c7ca7f Author: Sebastian Andrzej Siewior <bige...@linutronix.de> AuthorDate: Fri, 12 Aug 2016 19:49:43 +0200 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Fri, 2 Sep 2016 20:05:06 +0200
net/virtio-net: Convert to hotplug state machine 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 <bige...@linutronix.de> Cc: Mark Rutland <mark.rutl...@arm.com> Cc: "Michael S. Tsirkin" <m...@redhat.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: net...@vger.kernel.org Cc: Will Deacon <will.dea...@arm.com> Cc: virtualizat...@lists.linux-foundation.org Cc: r...@linutronix.de Link: http://lkml.kernel.org/r/1471024183-12666-7-git-send-email-bige...@linutronix.de Signed-off-by: Thomas Gleixner <t...@linutronix.de> --- drivers/net/virtio_net.c | 110 +++++++++++++++++++++++++++++++++++---------- include/linux/cpuhotplug.h | 1 + 2 files changed, 87 insertions(+), 24 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 1b5f531..fad84f3 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -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); + struct virtnet_info *vi = hlist_entry_safe(node, struct virtnet_info, + node); + virtnet_set_affinity(vi); + return 0; +} - switch(action & ~CPU_TASKS_FROZEN) { - case CPU_ONLINE: - case CPU_DOWN_FAILED: - case CPU_DEAD: - virtnet_set_affinity(vi); - break; - case CPU_DOWN_PREPARE: - virtnet_clean_affinity(vi, (long)hcpu); - break; - default: - break; - } +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; +} - return NOTIFY_OK; +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"); diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h index dcfe6191..b95f7ad 100644 --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -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,
