Message-ID: <9c7d400791aee24497f33fd1695770a88bb82fc8.camel@sipsolutions.net>
Subject: Re: [RFC PATCH] mac80211/cfg80211: update bss channel on channel
 switch
From:   Johannes Berg <johannes@sipsolutions.net>
To:     Sergey Matyukevich <sergey.matyukevich.os@quantenna.com>
Cc:     "linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
        Igor Mitsyanko <igor.mitsyanko.os@quantenna.com>,
        Arend van Spriel <arend.vanspriel@broadcom.com>
Date:   Mon, 25 Mar 2019 17:18:10 +0100
In-Reply-To: <20190325154443.elzp5n6nfngtg5vk@bars>
References: <20190321151915.16826-1-sergey.matyukevich.os@quantenna.com>
         <3d76d0d033609fff4e72448a9fd7d63ad1365cb2.camel@sipsolutions.net>
         <20190325154443.elzp5n6nfngtg5vk@bars>
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On Mon, 2019-03-25 at 15:44 +0000, Sergey Matyukevich wrote:
> > > 
> > I worry slightly about locking too, since there's no protection on the
> > wdev->current_bss pointer here.
> 
> Ok, I will add WARN_ON. As for locking, this function is supposed to be
> called with wdev->mtx held, see ASSERT_WDEV_LOCK. Do you think this may
> not be enough ? 

Oops, no, that's definitely sufficient. I missed it.

> I need to check mwifiex more carefully, but other cfg80211_ch_switch_notify
> users (mac80211, ath6kl, qtnfmac) seem to do that locking properly.

Well I guess they'd assert and then do something unsafe, so wouldn't
worry about it.

johannes