linux-kernel - Re: [RFC PATCH net-next 07/10] net: hibmcge: Implement rx

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Message-ID: <ff75f342-4894-4c06-922c-377701c461df@huawei.com>
Date: Thu, 1 Aug 2024 19:58:36 +0800
From: Jijie Shao <shaojijie@...wei.com>
To: Joe Damato <jdamato@...tly.com>
CC: <shaojijie@...wei.com>, "yisen.zhuang@...wei.com"
	<yisen.zhuang@...wei.com>, "salil.mehta@...wei.com" <salil.mehta@...wei.com>,
	"davem@...emloft.net" <davem@...emloft.net>, "edumazet@...gle.com"
	<edumazet@...gle.com>, "kuba@...nel.org" <kuba@...nel.org>,
	"pabeni@...hat.com" <pabeni@...hat.com>, "shenjian15@...wei.com"
	<shenjian15@...wei.com>, "wangpeiyang1@...wei.com" <wangpeiyang1@...wei.com>,
	"liuyonglong@...wei.com" <liuyonglong@...wei.com>, "sudongming (A)"
	<sudongming1@...wei.com>, <xujunsheng@...wei.com>, "shiyongbang (A)"
	<shiyongbang@...wei.com>, "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [RFC PATCH net-next 07/10] net: hibmcge: Implement rx_poll
 function to receive packets


on 2024/7/31 21:23, Joe Damato wrote:
> On Wed, Jul 31, 2024 at 05:42:42PM +0800, Jijie Shao wrote:
>> Implement rx_poll function to read the rx descriptor after
>> receiving the rx interrupt. Adjust the skb based on the
>> descriptor to complete the reception of the packet.
>>
>> Signed-off-by: Jijie Shao <shaojijie@...wei.com>
>> ---
>>   .../ethernet/hisilicon/hibmcge/hbg_common.h   |   5 +
>>   .../net/ethernet/hisilicon/hibmcge/hbg_hw.c   |  10 ++
>>   .../net/ethernet/hisilicon/hibmcge/hbg_hw.h   |   1 +
>>   .../net/ethernet/hisilicon/hibmcge/hbg_irq.c  |   9 +-
>>   .../net/ethernet/hisilicon/hibmcge/hbg_main.c |   2 +
>>   .../net/ethernet/hisilicon/hibmcge/hbg_reg.h  |   2 +
>>   .../hisilicon/hibmcge/hbg_reg_union.h         |  65 ++++++++
>>   .../net/ethernet/hisilicon/hibmcge/hbg_txrx.c | 157 +++++++++++++++++-
>>   8 files changed, 248 insertions(+), 3 deletions(-)
>   
>> diff --git a/drivers/net/ethernet/hisilicon/hibmcge/hbg_main.c b/drivers/net/ethernet/hisilicon/hibmcge/hbg_main.c
>> index 8efeea9b0c26..bb5f8321da8a 100644
>> --- a/drivers/net/ethernet/hisilicon/hibmcge/hbg_main.c
>> +++ b/drivers/net/ethernet/hisilicon/hibmcge/hbg_main.c
>> @@ -36,6 +36,7 @@ static int hbg_net_open(struct net_device *dev)
>>   		return 0;
>>   
>>   	netif_carrier_off(dev);
>> +	napi_enable(&priv->rx_ring.napi);
>>   	napi_enable(&priv->tx_ring.napi);
>>   	hbg_enable_intr(priv, true);
>>   	hbg_hw_mac_enable(priv, HBG_STATUS_ENABLE);
> In the future, it might be good to consider using:
>     - netif_napi_set_irq
>     - netif_queue_set_napi
>   
> to link NAPIs with IRQs and queues.
>
Sounds good, but I can't find these two functions in 6.4 kernel?

>
>> +static int hbg_rx_fill_buffers(struct hbg_priv *priv)
>> +{
>> +	struct hbg_ring *ring = &priv->rx_ring;
>> +	int ret;
>> +
>> +	while (!(hbg_fifo_is_full(priv, ring->dir) ||
>> +		 hbg_queue_is_full(ring->ntc, ring->ntu, ring))) {
>> +		ret = hbg_rx_fill_one_buffer(priv);
>> +		if (ret)
>> +			return ret;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static bool hbg_sync_data_from_hw(struct hbg_priv *priv,
>> +				  struct hbg_buffer *buffer)
>> +{
>> +	struct hbg_rx_desc *rx_desc;
>> +
>> +	/* make sure HW write desc complete */
>> +	dma_rmb();
>> +
>> +	dma_sync_single_for_cpu(&priv->pdev->dev, buffer->skb_dma,
>> +				buffer->skb_len, DMA_FROM_DEVICE);
>> +
>> +	rx_desc = (struct hbg_rx_desc *)buffer->skb->data;
>> +	return rx_desc->len != 0;
>> +}
> Have you looked into using the page pool to simplify some of the
> logic above?

Thanks, but I probably won't use it at the moment.

>
>> +static int hbg_napi_rx_poll(struct napi_struct *napi, int budget)
>> +{
>> +	struct hbg_ring *ring = container_of(napi, struct hbg_ring, napi);
>> +	struct hbg_priv *priv = ring->priv;
>> +	struct hbg_rx_desc *rx_desc;
>> +	struct hbg_buffer *buffer;
>> +	u32 packet_done = 0;
>> +
>> +	if (unlikely(!hbg_nic_is_open(priv))) {
>> +		napi_complete(napi);
>> +		return 0;
>> +	}
>> +
>> +	while (packet_done < budget) {
>> +		if (unlikely(hbg_queue_is_empty(ring->ntc, ring->ntu)))
>> +			break;
>> +
>> +		buffer = &ring->queue[ring->ntc];
>> +		if (unlikely(!buffer->skb))
>> +			goto next_buffer;
>> +
>> +		if (unlikely(!hbg_sync_data_from_hw(priv, buffer)))
>> +			break;
>> +
>> +		hbg_dma_unmap(buffer);
>> +
>> +		rx_desc = (struct hbg_rx_desc *)buffer->skb->data;
>> +		skb_reserve(buffer->skb, HBG_PACKET_HEAD_SIZE + NET_IP_ALIGN);
>> +		skb_put(buffer->skb, rx_desc->len);
>> +		buffer->skb->protocol = eth_type_trans(buffer->skb, priv->netdev);
>> +
>> +		priv->netdev->stats.rx_bytes += rx_desc->len;
>> +		priv->netdev->stats.rx_packets++;
>> +		netif_receive_skb(buffer->skb);
> Any reason why not napi_gro_receive ?

Is it OK if the MAC does not support gro?

>
>> +		buffer->skb = NULL;
>> +		hbg_rx_fill_one_buffer(priv);
>> +
>> +next_buffer:
>> +		hbg_queue_move_next(ntc, ring);
>> +		packet_done++;
>> +	}
>> +
>> +	hbg_rx_fill_buffers(priv);
>> +	if (packet_done >= budget)
>> +		return packet_done;
>> +
>> +	napi_complete(napi);
> Maybe:
>
>     if (napi_complete_done(napi))
>       hbg_irq_enable(priv, HBG_IRQ_RX, true);

okay, I will fix it in v2

Thanks again,

Jijie Shao