Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753166Ab1FBPnr (ORCPT ); Thu, 2 Jun 2011 11:43:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33884 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753117Ab1FBPno (ORCPT ); Thu, 2 Jun 2011 11:43:44 -0400 Date: Thu, 2 Jun 2011 18:42:59 +0300 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: Rusty Russell , Carsten Otte , Christian Borntraeger , linux390@de.ibm.com, Martin Schwidefsky , Heiko Carstens , Shirley Ma , lguest@lists.ozlabs.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, Krishna Kumar , Tom Lendacky , steved@us.ibm.com, habanero@linux.vnet.ibm.com Subject: [PATCHv2 RFC 1/4] virtio_ring: add capacity check API Message-ID: <8014f898ca6b768d7be626b83c617a1e84adfeb9.1307029009.git.mst@redhat.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Mutt-Fcc: =sent User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2141 Lines: 60 Add API to check ring capacity. Because of the option to use indirect buffers, this returns the worst case, not the normal case capacity. Signed-off-by: Michael S. Tsirkin --- drivers/virtio/virtio_ring.c | 8 ++++++++ include/linux/virtio.h | 5 +++++ 2 files changed, 13 insertions(+), 0 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 68b9136..23422f1 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -344,6 +344,14 @@ void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len) } EXPORT_SYMBOL_GPL(virtqueue_get_buf); +int virtqueue_min_capacity(struct virtqueue *_vq) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + + return vq->num_free; +} +EXPORT_SYMBOL_GPL(virtqueue_min_capacity); + void virtqueue_disable_cb(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 7108857..209220d 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -42,6 +42,9 @@ struct virtqueue { * vq: the struct virtqueue we're talking about. * len: the length written into the buffer * Returns NULL or the "data" token handed to add_buf. + * virtqueue_min_capacity: get the current capacity of the queue + * vq: the struct virtqueue we're talking about. + * Returns the current worst case capacity of the queue. * virtqueue_disable_cb: disable callbacks * vq: the struct virtqueue we're talking about. * Note that this is not necessarily synchronous, hence unreliable and only @@ -89,6 +92,8 @@ void virtqueue_kick(struct virtqueue *vq); void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len); +int virtqueue_min_capacity(struct virtqueue *vq); + void virtqueue_disable_cb(struct virtqueue *vq); bool virtqueue_enable_cb(struct virtqueue *vq); -- 1.7.5.53.gc233e -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/