netdev - Re: [PATCH 1/2] net: mvpp2: don't bring up on MAC address set

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Date:   Wed, 9 Nov 2016 14:22:11 +0100
From:   Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>
To:     Baruch Siach <baruch@...s.co.il>
Cc:     Marcin Wojtas <mw@...ihalf.com>, netdev@...r.kernel.org,
        Gregory Clement <gregory.clement@...e-electrons.com>
Subject: Re: [PATCH 1/2] net: mvpp2: don't bring up on MAC address set

Hello,

On Wed,  9 Nov 2016 14:56:33 +0200, Baruch Siach wrote:
> Current .ndo_set_mac_address implementation brings up the interface when revert
> to original address after failure succeeds. Fix this.
> 
> Signed-off-by: Baruch Siach <baruch@...s.co.il>

Indeed, this piece of code is not very smart.

> diff --git a/drivers/net/ethernet/marvell/mvpp2.c b/drivers/net/ethernet/marvell/mvpp2.c
> index 60227a3452a4..e427b4706726 100644
> --- a/drivers/net/ethernet/marvell/mvpp2.c
> +++ b/drivers/net/ethernet/marvell/mvpp2.c
> @@ -5686,9 +5686,8 @@ static int mvpp2_set_mac_address(struct net_device *dev, void *p)
>  		if (!err)
>  			return 0;
>  		/* Reconfigure parser to accept the original MAC address */
> -		err = mvpp2_prs_update_mac_da(dev, dev->dev_addr);
> -		if (err)
> -			goto error;
> +		mvpp2_prs_update_mac_da(dev, dev->dev_addr);
> +		goto error;

Wouldn't it make more sense to call mvpp2_prs_update_mac_da() under
the error: goto label?

But if you think beyond that, it is a bit crazy that to handle the
error case of mvpp2_prs_update_mac_da(), we have to call
mvpp2_prs_update_mac_da(), which is exactly the same function...

Perhaps it would be interesting to investigate what are the various
conditions for which mvpp2_prs_update_mac_da() fails, and see if we can
avoid them.

Best regards,

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com