From: Mark McLoughlin <markmc@redhat.com>
To: Alex Williamson <alex.williamson@hp.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>, kvm <kvm@vger.kernel.org>,
netdev <netdev@vger.kernel.org>
Subject: Re: [PATCH 2/4] virtio_net: Add a virtqueue for outbound control commands
Date: Wed, 14 Jan 2009 10:15:10 +0000 [thread overview]
Message-ID: <1231928110.4944.290.camel@localhost.localdomain> (raw)
In-Reply-To: <1231881797.9095.187.camel@bling>
On Tue, 2009-01-13 at 14:23 -0700, Alex Williamson wrote:
> This will be used for RX mode, MAC filter table, VLAN filtering, etc...
Looks very reasonable. I'm a bit wary of send_command() being
synchronous, but it probably makes sense.
Could do with some details in the commit log as to why this approach was
chosen over increasing virtio_net_config.
> Signed-off-by: Alex Williamson <alex.williamson@hp.com>
> ---
>
> drivers/net/virtio_net.c | 55 +++++++++++++++++++++++++++++++++++++++++++-
> include/linux/virtio_net.h | 3 ++
> 2 files changed, 57 insertions(+), 1 deletions(-)
>
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index e7700de..de348de 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -39,7 +39,7 @@ module_param(gso, bool, 0444);
> struct virtnet_info
> {
> struct virtio_device *vdev;
> - struct virtqueue *rvq, *svq;
> + struct virtqueue *rvq, *svq, *cvq;
> struct net_device *dev;
> struct napi_struct napi;
>
> @@ -603,6 +603,47 @@ static int virtnet_open(struct net_device *dev)
> return 0;
> }
>
> +static int virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
> + void *data, unsigned int len)
> +{
> + struct scatterlist sg[3];
> + struct {
> + u8 class;
> + u8 cmd;
> + } ctrl_cmd;
I'd like to see this defined in virtio_net_hdr.
Why the need for class/cmd? Why not just a single 16 bit command field?
> + u8 ctrl_status;
> + unsigned int tmp;
> + int i = 0;
> +
> + if (!vi->cvq)
> + return -EFAULT;
BUG_ON() probably makes more sense here.
> +
> + sg_init_table(sg, len ? 3 : 2);
> +
> + sg_set_buf(&sg[i++], &ctrl_cmd, sizeof(ctrl_cmd));
> + if (len)
> + sg_set_buf(&sg[i++], data, len);
> + sg_set_buf(&sg[i], &ctrl_status, sizeof(ctrl_status));
> +
> + ctrl_cmd.class = class;
> + ctrl_cmd.cmd = cmd;
> +
> + ctrl_status = ~0;
> +
> + if (vi->cvq->vq_ops->add_buf(vi->cvq, sg, i, 1, vi) != 0)
> + BUG();
> +
> + vi->cvq->vq_ops->kick(vi->cvq);
> +
> + while (!vi->cvq->vq_ops->get_buf(vi->cvq, &tmp))
> + cpu_relax();
> +
> + if (ctrl_status == VIRTIO_NET_OK)
> + return 0;
> + else
> + return -EFAULT;
Could be all on one line:
return ctrl_status ? -EFAULT : 0;
Cheers,
Mark.
next prev parent reply other threads:[~2009-01-14 10:15 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-13 21:23 [PATCH 2/4] virtio_net: Add a virtqueue for outbound control commands Alex Williamson
2009-01-14 10:15 ` Mark McLoughlin [this message]
2009-01-14 16:01 ` Alex Williamson
2009-01-14 16:37 ` Mark McLoughlin
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