On 29/03/2024 02:34, Ping-Ke Shih wrote:
>
>> I got another idea: if we have a guarantee that the two USB
>> interfaces are probed one at a time, then we can move the global
>> things into struct rtl_priv. The first probe call will allocate
>> the arrays and initialise the mutexes. The second probe call
>> will obtain those from the first struct rtl_priv:
>>
>> int rtl_usb_probe(struct usb_interface *intf, ...) {
>> udev = interface_to_usbdev(intf);
>> struct ieee80211_hw *first_hw = usb_get_intfdata(udev->actconfig->interface[0]);
>> struct rtl_priv *first_rtlpriv = rtl_priv(first_hw);
>>
>
> Could it have racing when obtaining mutexes from second probe?
> Should we need a lock to ensure the sequence?
>
> When driver is going to down, how can mutexes get free safely?
>
> It seems like we still need another global lock to ensure that.
>
I asked linux-usb and they said the two interfaces are probed
and disconnected one at a time, so it should be fine without
another mutex:
https://lore.kernel.org/linux-usb/2024032907-smokeless-imperial-f3f9@gregkh/
