netdev - Re: [PATCH v6 net-next 02/10] qed/qede: make devlink survive recovery

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Date:   Fri, 21 Aug 2020 11:18:00 -0700
From:   Jesse Brandeburg <jesse.brandeburg@...el.com>
To:     Igor Russkikh <irusskikh@...vell.com>
Cc:     <netdev@...r.kernel.org>, "David S . Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Ariel Elior <aelior@...vell.com>,
        Michal Kalderon <mkalderon@...vell.com>,
        "Alexander Lobakin" <alobakin@...vell.com>,
        Michal Kalderon <michal.kalderon@...vell.com>
Subject: Re: [PATCH v6 net-next 02/10] qed/qede: make devlink survive
 recovery

Igor Russkikh wrote:

> Devlink instance lifecycle was linked to qed_dev object,
> that caused devlink to be recreated on each recovery.
> 
> Changing it by making higher level driver (qede) responsible for its
> life. This way devlink now survives recoveries.
> 
> qede now stores devlink structure pointer as a part of its device
> object, devlink private data contains a linkage structure,
> qed_devlink.
> 
> Signed-off-by: Igor Russkikh <irusskikh@...vell.com>
> Signed-off-by: Alexander Lobakin <alobakin@...vell.com>
> Signed-off-by: Michal Kalderon <michal.kalderon@...vell.com>

<snip>

> diff --git a/drivers/net/ethernet/qlogic/qede/qede_main.c b/drivers/net/ethernet/qlogic/qede/qede_main.c
> index 140a392a81bb..93071d41afe4 100644
> --- a/drivers/net/ethernet/qlogic/qede/qede_main.c
> +++ b/drivers/net/ethernet/qlogic/qede/qede_main.c
> @@ -1170,10 +1170,23 @@ static int __qede_probe(struct pci_dev *pdev, u32 dp_module, u8 dp_level,
>  			rc = -ENOMEM;
>  			goto err2;
>  		}
> +
> +		edev->devlink = qed_ops->common->devlink_register(cdev);
> +		if (IS_ERR(edev->devlink)) {
> +			DP_NOTICE(edev, "Cannot register devlink\n");
> +			edev->devlink = NULL;
> +			/* Go on, we can live without devlink */
> +		}
>  	} else {
>  		struct net_device *ndev = pci_get_drvdata(pdev);
>  
>  		edev = netdev_priv(ndev);
> +
> +		if (edev && edev->devlink) {
> +			struct qed_devlink *qdl = devlink_priv(edev->devlink);
> +
> +			qdl->cdev = cdev;
> +		}
>  		edev->cdev = cdev;
>  		memset(&edev->stats, 0, sizeof(edev->stats));
>  		memcpy(&edev->dev_info, &dev_info, sizeof(dev_info));

same comment as against old version:

cppcheck notes that the edev check here before the && is either
unnecessary, or the original code had a possible null pointer
dereference.  I figure the code should just be
		if (edev->devlink) {

And I recommend that you try to run cppcheck --enable=all on your code,
it finds several style violations and a few other null pointer checks
that can be fixed up.