Hello!
On 7/31/20 9:43 AM, Yoshihiro Shimoda wrote:
>>>> From: Yuusuke Ashizuka, Sent: Thursday, July 30, 2020 7:02 PM
>>>> Subject: [PATCH v2] ravb: Fixed the problem that rmmod can not be done
>>>
>>> Thank you for the patch! I found a similar patch for another driver [1].
>>
>> It's not the same case -- that driver hadn't had the MDIO release code at all
>> before that patch.
>
> You're correct. I didn't realized it...
The patch description was somewhat incomplete there...
>>> So, we should apply this patch to the ravb driver.
>>
>> I believe the driver is innocent. :-)
>
> I hope so :)
Looks like I was wrong in this case. It's very fortunate that the MDIO bitbang
is not as popular as I thought.
> <snip>
>>>> $ lsmod
>>>> Module Size Used by
>>>> ravb 40960 1
>>>> $ rmmod ravb
>>>> rmmod: ERROR: Module ravb is in use
>>
>> Shouldn't the driver core call the remove() method for the affected devices
>> first, before checking the refcount?
>
> In this case, an mii bus of "mdiobb_ops bb_ops" is affected "device" by the ravb driver.
> And the ravb driver sets the owner of mii bus as THIS_MODULE like below:
>
> static struct mdiobb_ops bb_ops = {
> .owner = THIS_MODULE,
> .set_mdc = ravb_set_mdc,
> .set_mdio_dir = ravb_set_mdio_dir,
> .set_mdio_data = ravb_set_mdio_data,
> .get_mdio_data = ravb_get_mdio_data,
> };
>
> So, I don't think the driver core can call the remove() method for the mii bus
> because it's a part of the ravb driver...
And because the MDIO module just doesn't have the usual method! :-)
(I meant the EtherAVB driver's remove() method, and that one would be called after
a successful reference count check...)
> By the way, about the mdio-gpio driver, I'm wondering if the mdio-gpio
> driver cannot be removed by rmmod too. (perhaps, we need "rmmod -f" to remove it.)
You're on your own here. It's fortunate for this patch that I'm not currently loaded
at work! :-)
>>> By the way, I think you have to send this patch to the following maintainers too:
>>> # We can get it by using scripts/get_maintainers.pl.
>>> David S. Miller <davem@xxxxxxxxxxxxx> (maintainer:NETWORKING DRIVERS,commit_signer:8/8=100%)
>>> Jakub Kicinski <kuba@xxxxxxxxxx> (maintainer:NETWORKING DRIVERS)
Not critical, as DaveM uses the patchwork anyway. He started to be CC'ed on netdev patches
only recently. :-)
[...]
> Best regards,
> Yoshihiro Shimoda
MBR, Sergei
