netdev - Re: [PATCH net-next] alx: use fine-grained locking instead of RTNL

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Date:   Fri, 14 May 2021 13:59:35 +0300
From:   Nikolai Zhubr <zhubr.2@...il.com>
To:     Johannes Berg <johannes@...solutions.net>
CC:     netdev@...r.kernel.org
Subject: Re: [PATCH net-next] alx: use fine-grained locking instead of RTNL

Hi Johannes,

12.05.2021 13:19, Johannes Berg:
> In the alx driver, all locking depended on the RTNL, but
[...]
> @@ -232,7 +240,7 @@ static int alx_set_pauseparam(struct net_device *netdev,
>   	if (pause->autoneg)
>   		fc |= ALX_FC_ANEG;
>
> -	ASSERT_RTNL();
> +	mutex_lock(&alx->mtx);
>
>   	/* restart auto-neg for auto-mode */
>   	if (hw->adv_cfg&  ADVERTISED_Autoneg) {
> @@ -254,6 +262,7 @@ static int alx_set_pauseparam(struct net_device *netdev,
>   		alx_cfg_mac_flowcontrol(hw, fc);
>
>   	hw->flowctrl = fc;
> +	mutex_unlock(&alx->mtx);
>
>   	return 0;
>   }

Isn't this fragment missing a mutex_unlock(&alx->mtx) for the "return 
err" codepath in the middle? I'm not sure, its like very suspicious, 
please have a look.


Thank you,

Regards,
Nikolai