netdev - Re: [PATCH net-next 1/7] sfc: add devlink support for ef100

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Message-ID: <82a57ba1-bd28-3742-0027-a6a284569aee@amd.com>
Date:   Thu, 19 Jan 2023 17:52:42 +0000
From:   "Lucero Palau, Alejandro" <alejandro.lucero-palau@....com>
To:     Jakub Kicinski <kuba@...nel.org>,
        "Lucero Palau, Alejandro" <alejandro.lucero-palau@....com>
CC:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-net-drivers (AMD-Xilinx)" <linux-net-drivers@....com>,
        "davem@...emloft.net" <davem@...emloft.net>,
        "pabeni@...hat.com" <pabeni@...hat.com>,
        "edumazet@...gle.com" <edumazet@...gle.com>,
        "ecree.xilinx@...il.com" <ecree.xilinx@...il.com>
Subject: Re: [PATCH net-next 1/7] sfc: add devlink support for ef100


On 1/19/23 17:16, Jakub Kicinski wrote:
> On Thu, 19 Jan 2023 11:31:34 +0000 alejandro.lucero-palau@....com wrote:
>> +		devlink_unregister(efx->devlink);
>> +		devlink_free(efx->devlink);
> Please use the devl_ APIs and take the devl_lock() explicitly.
> Once you start adding sub-objects the API with implicit locking
> gets racy.


I need more help here.

The explicit locking you refer to, is it for this specific code only?

Also, I can not see all drivers locking/unlocking when doing 
devlink_unregister. Those doing it are calling code which invoke 
unregister devlink ports, like the NFP and I think ml5x as well.

In this case, no devlink port remains at this point, and no netdev either.

What is the potential race against?