netdev - Re: [PATCH v2] ravb: Fixed the problem that rmmod can not be done

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Message-ID: <ce81e95d-b3b0-7f1c-8f97-8bdcb23d5a8e@gmail.com>
Date:   Thu, 30 Jul 2020 19:04:01 +0300
From:   Sergei Shtylyov <sergei.shtylyov@...il.com>
To:     Yuusuke Ashizuka <ashiduka@...itsu.com>
Cc:     netdev@...r.kernel.org, linux-renesas-soc@...r.kernel.org
Subject: Re: [PATCH v2] ravb: Fixed the problem that rmmod can not be done

Hello!

On 7/30/20 1:01 PM, Yuusuke Ashizuka wrote:

> ravb is a module driver, but I cannot rmmod it after insmod it.

   Modular. And "insmod'ing it".

> ravb does mdio_init() at the time of probe, and module->refcnt is incremented
> by alloc_mdio_bitbang() called after that.

   That seems a common pattern, inlluding the Renesas sh_eth driver...

> Therefore, even if ifup is not performed, the driver is in use and rmmod cannot
> be performed.

   No, the driver's remove() method calls ravb_mdio_release() and that one calls
free_mdio_bitbang() that calls module_put(); the actual reason lies somewehre deeper
than this... Unfortunately I don't have the affected hardware anymore... :-(

[...]

MBR, Sergei