linux-kernel - Re: [PATCH/RFC net v2] net: dec: tulip: de2104x: Add shutdown handler to stop NIC

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Message-ID: <20201023130816.7abd450d@kicinski-fedora-PC1C0HJN.hsd1.ca.comcast.net>
Date:   Fri, 23 Oct 2020 13:08:16 -0700
From:   Jakub Kicinski <kuba@...nel.org>
To:     Moritz Fischer <mdf@...nel.org>
Cc:     netdev@...r.kernel.org, davem@...emloft.net,
        linux-parisc@...r.kernel.org, linux-kernel@...r.kernel.org,
        lucyyan@...gle.com, moritzf@...gle.com,
        James.Bottomley@...senpartnership.com
Subject: Re: [PATCH/RFC net v2] net: dec: tulip: de2104x: Add shutdown
 handler to stop NIC

On Thu, 22 Oct 2020 19:45:20 -0700 Moritz Fischer wrote:
> The driver does not implement a shutdown handler which leads to issues
> when using kexec in certain scenarios. The NIC keeps on fetching
> descriptors which gets flagged by the IOMMU with errors like this:
> 
> DMAR: DMAR:[DMA read] Request device [5e:00.0]fault addr fffff000
> DMAR: DMAR:[DMA read] Request device [5e:00.0]fault addr fffff000
> DMAR: DMAR:[DMA read] Request device [5e:00.0]fault addr fffff000
> DMAR: DMAR:[DMA read] Request device [5e:00.0]fault addr fffff000
> DMAR: DMAR:[DMA read] Request device [5e:00.0]fault addr fffff000
> 
> Signed-off-by: Moritz Fischer <mdf@...nel.org>

Change looks good.

Philosophically speaking I wonder if this is a fix or a feature.
If missing .shutdown callback was a bug we shouldn't accept drivers
which don't specify it :S

If you don't have a strong preference I'd rather apply this to net-next.

In any case - you need to respin, 'cause this does not apply to net
either :)

> diff --git a/drivers/net/ethernet/dec/tulip/de2104x.c b/drivers/net/ethernet/dec/tulip/de2104x.c
> index f1a2da15dd0a..6de0cd6cf4ca 100644
> --- a/drivers/net/ethernet/dec/tulip/de2104x.c
> +++ b/drivers/net/ethernet/dec/tulip/de2104x.c
> @@ -2180,11 +2180,19 @@ static int de_resume (struct pci_dev *pdev)
>  
>  #endif /* CONFIG_PM */
>  
> +static void de_shutdown(struct pci_dev *pdev)
> +{
> +	struct net_device *dev = pci_get_drvdata (pdev);

No space needed before parens

> +
> +	de_close(dev);
> +}
> +
>  static struct pci_driver de_driver = {
>  	.name		= DRV_NAME,
>  	.id_table	= de_pci_tbl,
>  	.probe		= de_init_one,
>  	.remove		= de_remove_one,
> +	.shutdown	= de_shutdown,
>  #ifdef CONFIG_PM
>  	.suspend	= de_suspend,
>  	.resume		= de_resume,