svn commit: r244200 - in head/sys/dev/virtio: block network scsi

[Bryan Venteicher]

On Thu, Dec 13, 2012 at 11:27 PM, Bryan Venteicher <bryanv at freebsd.org> wrote:
>
> Author: bryanv
> Date: Fri Dec 14 05:27:56 2012
> New Revision: 244200
> URL: http://svnweb.freebsd.org/changeset/base/244200
>
> Log:
>   virtio: Start taskqueues threads after attach cannot fail
>
>   If virtio_setup_intr() failed during boot, we would hang in
>   taskqueue_free() -> taskqueue_terminate() for all the taskq
>   threads to terminate. This will never happen since the
>   scheduler is not running by this point.
>

FWIW, this seems to be a pretty common bug across dozen of drivers.
bus_setup_intr() is not very likely to fail though.

For VirtIO, it is somewhat a moot point because the taskqueues are
about to be removed and replaced with ithreads as I should have done
in the beginning.


>   Reported by:  neel, grehan
>   Approved by:  grehan (mentor)
>
> Modified:
>   head/sys/dev/virtio/block/virtio_blk.c
>   head/sys/dev/virtio/network/if_vtnet.c
>   head/sys/dev/virtio/scsi/virtio_scsi.c
>
> Modified: head/sys/dev/virtio/block/virtio_blk.c
>
> ==============================================================================
> --- head/sys/dev/virtio/block/virtio_blk.c      Fri Dec 14 00:13:29 2012
> (r244199)
> +++ head/sys/dev/virtio/block/virtio_blk.c      Fri Dec 14 05:27:56 2012
> (r244200)
> @@ -338,8 +338,6 @@ vtblk_attach(device_t dev)
>                 device_printf(dev, "cannot allocate taskqueue\n");
>                 goto fail;
>         }
> -       taskqueue_start_threads(&sc->vtblk_tq, 1, PI_DISK, "%s taskq",
> -           device_get_nameunit(dev));
>
>         error = virtio_setup_intr(dev, INTR_TYPE_BIO | INTR_ENTROPY);
>         if (error) {
> @@ -347,6 +345,9 @@ vtblk_attach(device_t dev)
>                 goto fail;
>         }
>
> +       taskqueue_start_threads(&sc->vtblk_tq, 1, PI_DISK, "%s taskq",
> +           device_get_nameunit(dev));
> +
>         vtblk_create_disk(sc);
>
>         virtqueue_enable_intr(sc->vtblk_vq);
>
> Modified: head/sys/dev/virtio/network/if_vtnet.c
>
> ==============================================================================
> --- head/sys/dev/virtio/network/if_vtnet.c      Fri Dec 14 00:13:29 2012
> (r244199)
> +++ head/sys/dev/virtio/network/if_vtnet.c      Fri Dec 14 05:27:56 2012
> (r244200)
> @@ -439,18 +439,17 @@ vtnet_attach(device_t dev)
>                 ether_ifdetach(ifp);
>                 goto fail;
>         }
> -       taskqueue_start_threads(&sc->vtnet_tq, 1, PI_NET, "%s taskq",
> -           device_get_nameunit(dev));
>
>         error = virtio_setup_intr(dev, INTR_TYPE_NET);
>         if (error) {
>                 device_printf(dev, "cannot setup virtqueue interrupts\n");
> -               taskqueue_free(sc->vtnet_tq);
> -               sc->vtnet_tq = NULL;
>                 ether_ifdetach(ifp);
>                 goto fail;
>         }
>
> +       taskqueue_start_threads(&sc->vtnet_tq, 1, PI_NET, "%s taskq",
> +           device_get_nameunit(dev));
> +
>         /*
>          * Device defaults to promiscuous mode for backwards
>          * compatibility. Turn it off if possible.
>
> Modified: head/sys/dev/virtio/scsi/virtio_scsi.c
>
> ==============================================================================
> --- head/sys/dev/virtio/scsi/virtio_scsi.c      Fri Dec 14 00:13:29 2012
> (r244199)
> +++ head/sys/dev/virtio/scsi/virtio_scsi.c      Fri Dec 14 05:27:56 2012
> (r244200)
> @@ -347,12 +347,6 @@ vtscsi_attach(device_t dev)
>                 device_printf(dev, "cannot allocate taskqueue\n");
>                 goto fail;
>         }
> -       error = taskqueue_start_threads(&sc->vtscsi_tq, 1, PI_DISK, "%s
> taskq",
> -           device_get_nameunit(dev));
> -       if (error) {
> -               device_printf(dev, "cannot start taskqueue threads\n");
> -               goto fail;
> -       }
>
>         error = virtio_setup_intr(dev, INTR_TYPE_CAM);
>         if (error) {
> @@ -360,6 +354,9 @@ vtscsi_attach(device_t dev)
>                 goto fail;
>         }
>
> +       taskqueue_start_threads(&sc->vtscsi_tq, 1, PI_DISK, "%s taskq",
> +           device_get_nameunit(dev));
> +
>         vtscsi_enable_vqs_intr(sc);
>
>         /*