Return-path: Received: from mail-bk0-f54.google.com ([209.85.214.54]:55255 "EHLO mail-bk0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751977Ab3JBFfj convert rfc822-to-8bit (ORCPT ); Wed, 2 Oct 2013 01:35:39 -0400 Received: by mail-bk0-f54.google.com with SMTP id mz12so118277bkb.27 for ; Tue, 01 Oct 2013 22:35:37 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <8761th6ja6.fsf@kamboji.qca.qualcomm.com> References: <1380292567-2363-1-git-send-email-michal.kazior@tieto.com> <1380292567-2363-3-git-send-email-michal.kazior@tieto.com> <8761th6ja6.fsf@kamboji.qca.qualcomm.com> Date: Wed, 2 Oct 2013 07:35:37 +0200 Message-ID: (sfid-20131002_073542_620011_6D355160) Subject: Re: [PATCH 2/2] ath10k: fix scheduling while atomic bug From: Michal Kazior To: Kalle Valo Cc: ath10k@lists.infradead.org, linux-wireless Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 1 October 2013 18:35, Kalle Valo wrote: > Michal Kazior writes: > >> Recent WMI/HTC changes broke WEP with multiple >> keys. If WMI had no HTC TX credits to submit >> command for default wep index update it would >> trigger a bug. >> >> This simply moves the wep key index update to a >> worker. >> >> The key update may happen some time after first >> frame with a different wep key has been sent (i.e. >> some frames will be sent with old key). This was >> the case before too as WMI commands were >> asynchronous. >> >> Signed-off-by: Michal Kazior > > This looks problematic. Basically you just delay sending the WMI > command, but there's no guarantee that we actually have free credits at > the time of transmission. So to me it looks like this fixes the issue > just by luck. One thing at a time. This patch fixes 'scheduling while atomic' bug that was introduced with recent HTC/WMI changes. Multiple wep key handling had the same issue you point out before HTC/WMI changes. To fix the issue you mention we'd need to stop mac80211 queues, queue frame(s) with a new key on internal queue, schedule a work. The work should set new wep key index, send pending frames from internal queue and wake mac80211 queues. This is a bit more complex than it sounds though. Michał