From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: [PATCH v4 10/25] virtio: add API to enable VQs early Date: Mon, 13 Oct 2014 10:50:33 +0300 Message-ID: <1413114332-626-11-git-send-email-mst-v4@redhat.com> References: <1413114332-626-1-git-send-email-mst-v4@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Rusty Russell , virtualization@lists.linux-foundation.org, linux-scsi@vger.kernel.org, linux-s390@vger.kernel.org, v9fs-developer@lists.sourceforge.net, netdev@vger.kernel.org, kvm@vger.kernel.org, Amit Shah , Cornelia Huck , Christian Borntraeger , "David S. Miller" , Paolo Bonzini To: linux-kernel@vger.kernel.org Return-path: Content-Disposition: inline In-Reply-To: <1413114332-626-1-git-send-email-mst-v4@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org 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 --- include/linux/virtio_config.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h index e8f8f71..e36403b 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) { -- MST