From: Michael S. Tsirkin Date: Tue, 14 Oct 2014 23:52:30 +0000 (+1030) Subject: virtio: add API to enable VQs early X-Git-Tag: v3.18-rc1~28^2~15 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=3569db593081fd88bbd6df21b9b0531873f2042c;p=karo-tx-linux.git virtio: add API to enable VQs early virtio spec 0.9.X requires DRIVER_OK to be set before VQs are used, but some drivers use VQs before probe function returns. Since DRIVER_OK is set after probe, this violates the spec. Even though under virtio 1.0 transitional devices support this behaviour, we want to make it possible for those early callers to become spec compliant and eventually support non-transitional devices. Add API for drivers to call before using VQs. Sets DRIVER_OK internally. Signed-off-by: Michael S. Tsirkin Reviewed-by: Cornelia Huck Signed-off-by: Rusty Russell --- diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h index e8f8f71e843c..7f4ef66873ef 100644 --- a/include/linux/virtio_config.h +++ b/include/linux/virtio_config.h @@ -109,6 +109,23 @@ struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev, return vq; } +/** + * virtio_device_ready - enable vq use in probe function + * @vdev: the device + * + * Driver must call this to use vqs in the probe function. + * + * Note: vqs are enabled automatically after probe returns. + */ +static inline +void virtio_device_ready(struct virtio_device *dev) +{ + unsigned status = dev->config->get_status(dev); + + BUG_ON(status & VIRTIO_CONFIG_S_DRIVER_OK); + dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK); +} + static inline const char *virtio_bus_name(struct virtio_device *vdev) {