Re: [PATCH v7 10/30] net: wan: Add support for QMC HDLC

[Jakub Kicinski]

On Thu, 28 Sep 2023 09:06:28 +0200 Herve Codina wrote:
> +static int qmc_hdlc_close(struct net_device *netdev)
> +{
> +     struct qmc_hdlc *qmc_hdlc = netdev_to_qmc_hdlc(netdev);
> +     struct qmc_hdlc_desc *desc;
> +     int i;
> +
> +     netif_stop_queue(netdev);
> +
> +     qmc_chan_stop(qmc_hdlc->qmc_chan, QMC_CHAN_ALL);
> +     qmc_chan_reset(qmc_hdlc->qmc_chan, QMC_CHAN_ALL);

stopping the queue looks a bit racy, a completion may come in 
and restart the queue

> +     for (i = 0; i < ARRAY_SIZE(qmc_hdlc->tx_descs); i++) {
> +             desc = &qmc_hdlc->tx_descs[i];
> +             if (!desc->skb)
> +                     continue;
> +             dma_unmap_single(qmc_hdlc->dev, desc->dma_addr, desc->dma_size,
> +                              DMA_TO_DEVICE);
> +             kfree_skb(desc->skb);
> +             desc->skb = NULL;
> +     }
> +
> +     for (i = 0; i < ARRAY_SIZE(qmc_hdlc->rx_descs); i++) {
> +             desc = &qmc_hdlc->rx_descs[i];
> +             if (!desc->skb)
> +                     continue;
> +             dma_unmap_single(qmc_hdlc->dev, desc->dma_addr, desc->dma_size,
> +                              DMA_FROM_DEVICE);
> +             kfree_skb(desc->skb);
> +             desc->skb = NULL;
> +     }
> +
> +     hdlc_close(netdev);