On 03/20/2013 03:24 PM, Asias He wrote:

On Wed, Mar 20, 2013 at 03:01:24PM +0800, Wanlong Gao wrote:

quoted

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 <redacted>
Reviewed-by: Asias He <redacted>
---
 drivers/scsi/virtio_scsi.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index 13d7672..0ad9017 100644
--- 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);
 }

-- 
1.8.2.rc2

This one does not apply on top of virtio-next + patch 1-4 in this series.

I'm very sorry.

This fault is because I modified the 4/5 from 
"/* if the affinity hint is set for virtqueues */"
to
"/* If the affinity hint is set for virtqueues */"
by hand.

You can also change "If" to "if" in 5/5 to apply this patch without 3-way merge.

Thanks,
Wanlong Gao