[SCSI] virtio-scsi: Add vdrv->scan for post VIRTIO_CONFIG_S_DRIVER_OK LUN scanning

This patch changes virtio-scsi to use a new virtio_driver->scan() callback
so that scsi_scan_host() can be properly invoked once virtio_dev_probe() has
set add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK) to signal active virtio-ring
operation, instead of from within virtscsi_probe().

This fixes a bug where SCSI LUN scanning for both virtio-scsi-raw and
virtio-scsi/tcm_vhost setups was happening before VIRTIO_CONFIG_S_DRIVER_OK
had been set, causing VIRTIO_SCSI_S_BAD_TARGET to occur.  This fixes a bug
with virtio-scsi/tcm_vhost where LUN scan was not detecting LUNs.

Tested with virtio-scsi-raw + virtio-scsi/tcm_vhost w/ IBLOCK on 3.5-rc2 code.

Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index ae3bef7..c7030fb 100644 (file)
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -571,6 +571,13 @@ static struct virtio_scsi_target_state *virtscsi_alloc_tgt(
        return tgt;
 }
 
+static void virtscsi_scan(struct virtio_device *vdev)
+{
+       struct Scsi_Host *shost = (struct Scsi_Host *)vdev->priv;
+
+       scsi_scan_host(shost);
+}
+
 static void virtscsi_remove_vqs(struct virtio_device *vdev)
 {
        struct Scsi_Host *sh = virtio_scsi_host(vdev);
@@ -677,9 +684,10 @@ static int __devinit virtscsi_probe(struct virtio_device *vdev)
        err = scsi_add_host(shost, &vdev->dev);
        if (err)
                goto scsi_add_host_failed;
-
-       scsi_scan_host(shost);
-
+       /*
+        * scsi_scan_host() happens in virtscsi_scan() via virtio_driver->scan()
+        * after VIRTIO_CONFIG_S_DRIVER_OK has been set..
+        */
        return 0;
 
 scsi_add_host_failed:
@@ -735,6 +743,7 @@ static struct virtio_driver virtio_scsi_driver = {
        .driver.owner = THIS_MODULE,
        .id_table = id_table,
        .probe = virtscsi_probe,
+       .scan = virtscsi_scan,
 #ifdef CONFIG_PM
        .freeze = virtscsi_freeze,
        .restore = virtscsi_restore,

diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index f355807..c3b3f7f 100644 (file)
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -141,8 +141,11 @@ static int virtio_dev_probe(struct device *_d)
        err = drv->probe(dev);
        if (err)
                add_status(dev, VIRTIO_CONFIG_S_FAILED);
-       else
+       else {
                add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
+               if (drv->scan)
+                       drv->scan(dev);
+       }
 
        return err;
 }

diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 8efd28a..a1ba8bb 100644 (file)
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -92,6 +92,7 @@ struct virtio_driver {
        const unsigned int *feature_table;
        unsigned int feature_table_size;
        int (*probe)(struct virtio_device *dev);
+       void (*scan)(struct virtio_device *dev);
        void (*remove)(struct virtio_device *dev);
        void (*config_changed)(struct virtio_device *dev);
 #ifdef CONFIG_PM