virtio-scsi: reset virtqueue affinity when doing cpu hotplug

Add hot cpu notifier to reset the request virtqueue affinity
when doing cpu hotplug.

Cc: linux-scsi@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Reviewed-by: Asias He <asias@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index 8dcdef0..2168258 100644 (file)
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -110,6 +110,9 @@ struct virtio_scsi {
        /* If the affinity hint is set for virtqueues */
        bool affinity_hint_set;
 
+       /* CPU hotplug notifier */
+       struct notifier_block nb;
+
        struct virtio_scsi_vq ctrl_vq;
        struct virtio_scsi_vq event_vq;
        struct virtio_scsi_vq req_vqs[];
@@ -762,6 +765,23 @@ 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)
+{
+       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;
+}
+
 static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
                             struct virtqueue *vq)
 {
@@ -884,6 +904,13 @@ 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");
+               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);
        shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
@@ -921,6 +948,8 @@ static void virtscsi_remove(struct virtio_device *vdev)
 
        scsi_remove_host(shost);
 
+       unregister_hotcpu_notifier(&vscsi->nb);
+
        virtscsi_remove_vqs(vdev);
        scsi_host_put(shost);
 }