linux-kernel - Re: [PATCH net 2/4] net: ll_temac: Add more error handling of dma_map

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Message-ID: <87v9o18xqd.fsf@geanix.com>
Date:   Thu, 20 Feb 2020 09:32:58 +0100
From:   Esben Haabendal <esben@...nix.com>
To:     David Miller <davem@...emloft.net>
Cc:     netdev@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, andrew@...n.ch,
        michal.simek@...inx.com, ynezz@...e.cz
Subject: Re: [PATCH net 2/4] net: ll_temac: Add more error handling of dma_map_single() calls

David Miller <davem@...emloft.net> writes:

> From: Esben Haabendal <esben@...nix.com>
> Date: Wed, 19 Feb 2020 11:54:00 +0100
>
>> @@ -863,12 +865,13 @@ temac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
>>  	skb_dma_addr = dma_map_single(ndev->dev.parent, skb->data,
>>  				      skb_headlen(skb), DMA_TO_DEVICE);
>>  	cur_p->len = cpu_to_be32(skb_headlen(skb));
>> +	if (WARN_ON_ONCE(dma_mapping_error(ndev->dev.parent, skb_dma_addr)))
>> +		return NETDEV_TX_BUSY;
>
> The appropriate behavior in this situation is to drop the packet and return
> NETDEV_TX_OK.

Ok, and I guess the same goes for the error handling of dma_map_single()
of one of the fragments later in same function.

/Esben