Re: [PATCH] wifi: wilc1000: fix kernel oops during interface down during background scan

[Kalle Valo <kvalo@kernel.org>]

<Ajay.Kathat@microchip.com> writes:

>>> @@ -781,13 +776,15 @@ static int wilc_mac_close(struct net_device *ndev)
>>>       if (vif->ndev) {
>>>               netif_stop_queue(vif->ndev);
>>>
>>> +             if (wl->open_ifcs == 0)
>>> +                     wl->close = 1;
>>> +
>> 
>> wl-close is an int, I wonder if it's racy to int as a flag like this? In
>> cases like this I usually use set_bit() & co because those guarantee
>> atomicity, though don't know if that's overkill.
>> 
>
> I think it's a good idea to use an atomic operation but I am not sure if
> using atomic for 'wl->close' will have much impact. For instance, if any
> new work gets added to the workqueue before the 'wl->close=1' is fully
> completed, then that work would get executed as normal.

Sure, this is most likely a small race condition. But still a race.

> However, I feel it's safe to define 'wl->close' as atomic_t type. I will
> prepare the conversion patch and will try to include it along with the
> updated version of this patch.

Why atomic_t? You only use values 0 and 1 so test_bit() and set_bit()
sounds more approriate to me.


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