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Subject: Re: when to use wdev_lock()
From: Johannes Berg <johannes@sipsolutions.net>
To: Arend van Spriel <arend.vanspriel@broadcom.com>
Cc: linux-wireless <linux-wireless@vger.kernel.org>
Date: Wed, 17 May 2017 15:15:58 +0200
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Hi Arend,

Sorry for the long delay.

> I bumped into use of wdev_lock() again with 802.1X 4-way-hs offload 
> stuff. So for .set_pmk() and .del_pmk() it takes wdev_lock(). Is
> there a  rule of thumb when this lock is needed. What is it
> protecting in general  and in the case of pmk configuration.

No, unfortunately it's not very well defined.

One thing that drove this is that mac80211 (and perhaps some full-mac
drivers) uses the same lock to prevent races between their own and
cfg80211's state. So some of the locking is driven by that as well.

I think it may have been done here just for consistency with other
calls.

johannes