From: Johannes Berg <johannes@sipsolutions.net>
To: Michal Kazior <michal.kazior@tieto.com>
Cc: linux-wireless <linux-wireless@vger.kernel.org>
Subject: Re: [PATCH 3/3] mac80211: make csa_currnet_counter atomic
Date: Thu, 22 May 2014 16:36:03 +0200 [thread overview]
Message-ID: <1400769363.4174.20.camel@jlt4.sipsolutions.net> (raw)
In-Reply-To: <CA+BoTQ=ubXxkyJZErm9eWQqPNWxAz4XZqgW=PLydWZR5hS+68g@mail.gmail.com> (sfid-20140522_160306_331852_888C31FB)
On Thu, 2014-05-22 at 16:03 +0200, Michal Kazior wrote:
> I was thinking the same. The problem is without an atomic variable the
> code is simply oblivious to SMP. What if your beacon interrupts are
> spread across different CPU and your caches haven't synced yet? I
> suppose this is practically unlikely considering beacon intervals but
> still..
No, this can't happen - Linux only runs on cache-coherent SMP
architectures.
The only race that could happen is the "lost update" etc. but that's
obviously avoided by the driver synchronising/spacing the updates.
johannes
prev parent reply other threads:[~2014-05-22 14:36 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-22 13:28 [PATCH 0/3] mac80211: fix csa counters Michal Kazior
2014-05-22 13:28 ` [PATCH 1/3] mac80211: move csa counters from sdata to beacon/presp Michal Kazior
2014-05-22 13:43 ` Johannes Berg
2014-05-22 13:53 ` Michal Kazior
2014-05-22 14:37 ` Johannes Berg
2014-05-22 14:38 ` Johannes Berg
2014-05-22 13:28 ` [PATCH 2/3] mac80211: use csa counter offsets instead of csa_active Michal Kazior
2014-05-22 13:45 ` Johannes Berg
2014-05-22 13:59 ` Michal Kazior
2014-05-22 14:38 ` Johannes Berg
2014-05-22 13:28 ` [PATCH 3/3] mac80211: make csa_currnet_counter atomic Michal Kazior
2014-05-22 13:50 ` Johannes Berg
2014-05-22 14:03 ` Michal Kazior
2014-05-22 14:36 ` Johannes Berg [this message]
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