Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull CPU hotplug updates from Thomas Gleixner:
 "Yet another batch of cpu hotplug core updates and conversions:

   - Provide core infrastructure for multi instance drivers so the
     drivers do not have to keep custom lists.

   - Convert custom lists to the new infrastructure. The block-mq custom
     list conversion comes through the block tree and makes the diffstat
     tip over to more lines removed than added.

   - Handle unbalanced hotplug enable/disable calls more gracefully.

   - Remove the obsolete CPU_STARTING/DYING notifier support.

   - Convert another batch of notifier users.

   The relayfs changes which conflicted with the conversion have been
   shipped to me by Andrew.

   The remaining lot is targeted for 4.10 so that we finally can remove
   the rest of the notifiers"

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (46 commits)
  cpufreq: Fix up conversion to hotplug state machine
  blk/mq: Reserve hotplug states for block multiqueue
  x86/apic/uv: Convert to hotplug state machine
  s390/mm/pfault: Convert to hotplug state machine
  mips/loongson/smp: Convert to hotplug state machine
  mips/octeon/smp: Convert to hotplug state machine
  fault-injection/cpu: Convert to hotplug state machine
  padata: Convert to hotplug state machine
  cpufreq: Convert to hotplug state machine
  ACPI/processor: Convert to hotplug state machine
  virtio scsi: Convert to hotplug state machine
  oprofile/timer: Convert to hotplug state machine
  block/softirq: Convert to hotplug state machine
  lib/irq_poll: Convert to hotplug state machine
  x86/microcode: Convert to hotplug state machine
  sh/SH-X3 SMP: Convert to hotplug state machine
  ia64/mca: Convert to hotplug state machine
  ARM/OMAP/wakeupgen: Convert to hotplug state machine
  ARM/shmobile: Convert to hotplug state machine
  arm64/FP/SIMD: Convert to hotplug state machine
  ...

1 files changed, 49 insertions, 27 deletions

diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index 7dbbb29d24c6..deefab3a94d0 100644
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -107,8 +107,8 @@ struct virtio_scsi {
 	/* If the affinity hint is set for virtqueues */
 	bool affinity_hint_set;
 
-	/* CPU hotplug notifier */
-	struct notifier_block nb;
+	struct hlist_node node;
+	struct hlist_node node_dead;
 
 	/* Protected by event_vq lock */
 	bool stop_events;
@@ -118,6 +118,7 @@ struct virtio_scsi {
 	struct virtio_scsi_vq req_vqs[];
 };
 
+static enum cpuhp_state virtioscsi_online;
 static struct kmem_cache *virtscsi_cmd_cache;
 static mempool_t *virtscsi_cmd_pool;
 
@@ -852,21 +853,33 @@ static void virtscsi_set_affinity(struct virtio_scsi *vscsi, bool affinity)
 	put_online_cpus();
 }
 
-static int virtscsi_cpu_callback(struct notifier_block *nfb,
-				 unsigned long action, void *hcpu)
+static int virtscsi_cpu_online(unsigned int cpu, struct hlist_node *node)
 {
-	struct virtio_scsi *vscsi = container_of(nfb, struct virtio_scsi, nb);
-	switch(action) {
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		__virtscsi_set_affinity(vscsi, true);
-		break;
-	default:
-		break;
-	}
-	return NOTIFY_OK;
+	struct virtio_scsi *vscsi = hlist_entry_safe(node, struct virtio_scsi,
+						     node);
+	__virtscsi_set_affinity(vscsi, true);
+	return 0;
+}
+
+static int virtscsi_cpu_notif_add(struct virtio_scsi *vi)
+{
+	int ret;
+
+	ret = cpuhp_state_add_instance(virtioscsi_online, &vi->node);
+	if (ret)
+		return ret;
+
+	ret = cpuhp_state_add_instance(CPUHP_VIRT_SCSI_DEAD, &vi->node_dead);
+	if (ret)
+		cpuhp_state_remove_instance(virtioscsi_online, &vi->node);
+	return ret;
+}
+
+static void virtscsi_cpu_notif_remove(struct virtio_scsi *vi)
+{
+	cpuhp_state_remove_instance_nocalls(virtioscsi_online, &vi->node);
+	cpuhp_state_remove_instance_nocalls(CPUHP_VIRT_SCSI_DEAD,
+					    &vi->node_dead);
 }
 
 static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
@@ -929,8 +942,6 @@ static int virtscsi_init(struct virtio_device *vdev,
 		virtscsi_init_vq(&vscsi->req_vqs[i - VIRTIO_SCSI_VQ_BASE],
 				 vqs[i]);
 
-	virtscsi_set_affinity(vscsi, true);
-
 	virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
 	virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
 
@@ -987,12 +998,9 @@ static int virtscsi_probe(struct virtio_device *vdev)
 	if (err)
 		goto virtscsi_init_failed;
 
-	vscsi->nb.notifier_call = &virtscsi_cpu_callback;
-	err = register_hotcpu_notifier(&vscsi->nb);
-	if (err) {
-		pr_err("registering cpu notifier failed\n");
+	err = virtscsi_cpu_notif_add(vscsi);
+	if (err)
 		goto scsi_add_host_failed;
-	}
 
 	cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1;
 	shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
@@ -1049,7 +1057,7 @@ static void virtscsi_remove(struct virtio_device *vdev)
 
 	scsi_remove_host(shost);
 
-	unregister_hotcpu_notifier(&vscsi->nb);
+	virtscsi_cpu_notif_remove(vscsi);
 
 	virtscsi_remove_vqs(vdev);
 	scsi_host_put(shost);
@@ -1061,7 +1069,7 @@ static int virtscsi_freeze(struct virtio_device *vdev)
 	struct Scsi_Host *sh = virtio_scsi_host(vdev);
 	struct virtio_scsi *vscsi = shost_priv(sh);
 
-	unregister_hotcpu_notifier(&vscsi->nb);
+	virtscsi_cpu_notif_remove(vscsi);
 	virtscsi_remove_vqs(vdev);
 	return 0;
 }
@@ -1076,12 +1084,11 @@ static int virtscsi_restore(struct virtio_device *vdev)
 	if (err)
 		return err;
 
-	err = register_hotcpu_notifier(&vscsi->nb);
+	err = virtscsi_cpu_notif_add(vscsi);
 	if (err) {
 		vdev->config->del_vqs(vdev);
 		return err;
 	}
-
 	virtio_device_ready(vdev);
 
 	if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
@@ -1136,6 +1143,16 @@ static int __init init(void)
 		pr_err("mempool_create() for virtscsi_cmd_pool failed\n");
 		goto error;
 	}
+	ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
+				      "scsi/virtio:online",
+				      virtscsi_cpu_online, NULL);
+	if (ret < 0)
+		goto error;
+	virtioscsi_online = ret;
+	ret = cpuhp_setup_state_multi(CPUHP_VIRT_SCSI_DEAD, "scsi/virtio:dead",
+				      NULL, virtscsi_cpu_online);
+	if (ret)
+		goto error;
 	ret = register_virtio_driver(&virtio_scsi_driver);
 	if (ret < 0)
 		goto error;
@@ -1151,12 +1168,17 @@ error:
 		kmem_cache_destroy(virtscsi_cmd_cache);
 		virtscsi_cmd_cache = NULL;
 	}
+	if (virtioscsi_online)
+		cpuhp_remove_multi_state(virtioscsi_online);
+	cpuhp_remove_multi_state(CPUHP_VIRT_SCSI_DEAD);
 	return ret;
 }
 
 static void __exit fini(void)
 {
 	unregister_virtio_driver(&virtio_scsi_driver);
+	cpuhp_remove_multi_state(virtioscsi_online);
+	cpuhp_remove_multi_state(CPUHP_VIRT_SCSI_DEAD);
 	mempool_destroy(virtscsi_cmd_pool);
 	kmem_cache_destroy(virtscsi_cmd_cache);
 }