On Mon, Jul 25, 2022 at 3:23 PM Xuan Zhuo [off-list ref] wrote:

On Mon, 25 Jul 2022 14:57:11 +0800, Jason Wang [off-list ref] wrote:

quoted

On Mon, Jul 25, 2022 at 2:43 PM Xuan Zhuo [off-list ref] wrote:

quoted

On Thu, 21 Jul 2022 17:25:59 +0800, Jason Wang [off-list ref] wrote:

quoted

在 2022/7/20 11:04, Xuan Zhuo 写道:

quoted

This patch implements the resize function of the rx queues.
Based on this function, it is possible to modify the ring num of the
queue.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
  drivers/net/virtio_net.c | 22 ++++++++++++++++++++++
  1 file changed, 22 insertions(+)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index fe4dc43c05a1..1115a8b59a08 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c

@@ -278,6 +278,8 @@ struct padded_vnet_hdr {
    char padding[12];
  };

+static void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf);
+
  static bool is_xdp_frame(void *ptr)
  {
    return (unsigned long)ptr & VIRTIO_XDP_FLAG;

@@ -1846,6 +1848,26 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
    return NETDEV_TX_OK;
  }

+static int virtnet_rx_resize(struct virtnet_info *vi,
+                        struct receive_queue *rq, u32 ring_num)
+{
+   int err, qindex;
+
+   qindex = rq - vi->rq;
+
+   napi_disable(&rq->napi);

We need to disable refill work as well. So this series might need
rebasing on top of

https://lore.kernel.org/netdev/20220704074859.16912-1-jasowang@redhat.com/ (local)

I understand that your patch is used to solve the situation where dev is
destoryed but refill work is running.

And is there such a possibility here?

E.g the refill work runs in parallel with this function?

napi_disable enables lock-like functionality. So I think it's safe.

Ok, right, since there will be a napi_enable() soon afterwards.

So

Acked-by: Jason Wang <jasowang@redhat.com>

Thanks

Thanks.

quoted

Thanks

quoted

Or is there any other scenario that I'm
not expecting?

Thanks.

quoted

I will send a new version (probably tomorrow).

Thanks

quoted

+
+   err = virtqueue_resize(rq->vq, ring_num, virtnet_rq_free_unused_buf);
+   if (err)
+           netdev_err(vi->dev, "resize rx fail: rx queue index: %d err: %d\n", qindex, err);
+
+   if (!try_fill_recv(vi, rq, GFP_KERNEL))
+           schedule_delayed_work(&vi->refill, 0);
+
+   virtnet_napi_enable(rq->vq, &rq->napi);
+   return err;
+}
+
  /*
   * Send command via the control virtqueue and check status.  Commands
   * supported by the hypervisor, as indicated by feature bits, should