netdev - Re: [PATCH vhost 08/22] virtio_net: virtnet_poll

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Message-ID: <20231012051159-mutt-send-email-mst@kernel.org>
Date: Thu, 12 Oct 2023 05:13:11 -0400
From: "Michael S. Tsirkin" <mst@...hat.com>
To: Xuan Zhuo <xuanzhuo@...ux.alibaba.com>
Cc: virtualization@...ts.linux-foundation.org,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Jason Wang <jasowang@...hat.com>,
	Alexei Starovoitov <ast@...nel.org>,
	Daniel Borkmann <daniel@...earbox.net>,
	Jesper Dangaard Brouer <hawk@...nel.org>,
	John Fastabend <john.fastabend@...il.com>, netdev@...r.kernel.org,
	bpf@...r.kernel.org
Subject: Re: [PATCH vhost 08/22] virtio_net: virtnet_poll_tx support
 rescheduled

On Wed, Oct 11, 2023 at 05:27:14PM +0800, Xuan Zhuo wrote:
> virtnet_poll_tx() support to return budget when busy to be rescheduled.
> 
> When retval < budget, napi_poll() in dev.c will exit directly. And
> virtqueue_napi_complete() will be called to close napi.
> 
> When retval == budget, the napi_poll() in dev.c will re-add napi to the
> queue.
> 
> The purpose of this patch is to support xsk xmit in virtio_poll_tx() for
> subsequent patch.
> 
> Signed-off-by: Xuan Zhuo <xuanzhuo@...ux.alibaba.com>
> ---
>  drivers/net/virtio/main.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/net/virtio/main.c b/drivers/net/virtio/main.c
> index bcfd31a55076..f32cfa189972 100644
> --- a/drivers/net/virtio/main.c
> +++ b/drivers/net/virtio/main.c
> @@ -1976,6 +1976,7 @@ static int virtnet_poll_tx(struct napi_struct *napi, int budget)
>  	struct virtnet_info *vi = sq->vq->vdev->priv;
>  	unsigned int index = vq2txq(sq->vq);
>  	struct netdev_queue *txq;
> +	int busy = 0;
>  	int opaque;
>  	bool done;
>  
> @@ -1993,6 +1994,11 @@ static int virtnet_poll_tx(struct napi_struct *napi, int budget)
>  	if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS)
>  		netif_tx_wake_queue(txq);
>  
> +	if (busy) {
> +		__netif_tx_unlock(txq);
> +		return budget;
> +	}
> +
>  	opaque = virtqueue_enable_cb_prepare(sq->vq);
>  
>  	done = napi_complete_done(napi, 0);

This just adds a bit of dead code.
Pls just squash into that patch.

> -- 
> 2.32.0.3.g01195cf9f