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