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Message-ID: <ddb8233c-ad3b-ef2a-36c0-5986d0f1696c@ti.com>
Date:   Mon, 31 Jul 2023 10:27:37 +0530
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Subject: Re: [EXTERNAL] Re: [PATCH v12 06/10] net: ti: icssg-prueth: Add ICSSG
 ethernet driver
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To:     Jakub Kicinski <kuba@kernel.org>,
        MD Danish Anwar <danishanwar@ti.com>
CC:     Randy Dunlap <rdunlap@infradead.org>,
        Roger Quadros <rogerq@kernel.org>,
        Simon Horman <simon.horman@corigine.com>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        Andrew Lunn <andrew@lunn.ch>,
        Richard Cochran <richardcochran@gmail.com>,
        Conor Dooley <conor+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Eric Dumazet <edumazet@google.com>,
        "David S. Miller" <davem@davemloft.net>, <nm@ti.com>, <srk@ti.com>,
        <linux-kernel@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <netdev@vger.kernel.org>, <linux-omap@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>
References: <20230727112827.3977534-1-danishanwar@ti.com>
 <20230727112827.3977534-7-danishanwar@ti.com>
 <20230728172419.702b4ac0@kernel.org>
From:   Md Danish Anwar <a0501179@ti.com>
Organization: Texas Instruments
In-Reply-To: <20230728172419.702b4ac0@kernel.org>
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Hi Jakub,

On 29/07/23 5:54 am, Jakub Kicinski wrote:
> On Thu, 27 Jul 2023 16:58:23 +0530 MD Danish Anwar wrote:
>> +static int emac_tx_complete_packets(struct prueth_emac *emac, int chn,
>> +				    int budget)
>> +{
>> +	struct net_device *ndev = emac->ndev;
>> +	struct cppi5_host_desc_t *desc_tx;
>> +	struct netdev_queue *netif_txq;
>> +	struct prueth_tx_chn *tx_chn;
>> +	unsigned int total_bytes = 0;
>> +	struct sk_buff *skb;
>> +	dma_addr_t desc_dma;
>> +	int res, num_tx = 0;
>> +	void **swdata;
>> +
>> +	tx_chn = &emac->tx_chns[chn];
>> +
>> +	while (budget) {
>> +		res = k3_udma_glue_pop_tx_chn(tx_chn->tx_chn, &desc_dma);
>> +		if (res == -ENODATA)
>> +			break;
> 
> You shouldn't limit the number of serviced packets to budget for Tx
> NAPI.
> 
> https://docs.kernel.org/next/networking/napi.html#driver-api
> 
>> +	skb->dev = ndev;
>> +	if (!netif_running(skb->dev)) {
>> +		dev_kfree_skb_any(skb);
>> +		return 0;
>> +	}
> 
> why do you check if the interface is running?
> If a packet arrives, it means the interface is running..
> 

Sure, I will drop this if condition.

>> +drop_free_descs:
>> +	prueth_xmit_free(tx_chn, first_desc);
>> +drop_stop_q:
>> +	netif_tx_stop_queue(netif_txq);
> 
> Do not stop the queue on DMA errors. If the queue is empty nothing
> will wake it up. Queue should only be stopped based on occupancy.
> 

Sure, I will try to make sure we only stop queue based on occupancy.

>> +	dev_kfree_skb_any(skb);
>> +
>> +	/* error */
>> +	ndev->stats.tx_dropped++;
>> +	netdev_err(ndev, "tx: error: %d\n", ret);
>> +
>> +	return ret;

-- 
Thanks and Regards,
Danish.