From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EDD19C41602 for ; Mon, 12 Apr 2021 09:31:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D455361209 for ; Mon, 12 Apr 2021 09:31:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242319AbhDLJ2P (ORCPT ); Mon, 12 Apr 2021 05:28:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:57182 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239959AbhDLJEO (ORCPT ); Mon, 12 Apr 2021 05:04:14 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id A6C546125F; Mon, 12 Apr 2021 09:01:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1618218109; bh=pvq29ehwiw1el+BH46uOAN2FjF35TIZooBak9YNdEj8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Y8LyWw4h7Q2rTFZDBydXTBC9Yf2WjNhdQE9n6Hrt8+5H/6GZd3KcM7msZXpRtmVb/ A7NOSbabFRVTJe439Vyx5WY5I5UR2QtfKs2ZPWg4G9s/Vf8WA8DLNkSKZ5583hZzVs ZncngmIoZCzNdQLFIXcGyDn6DvSH9bvFtPpjdr1k= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= , Johannes Berg Subject: [PATCH 5.11 074/210] mac80211: fix TXQ AC confusion Date: Mon, 12 Apr 2021 10:39:39 +0200 Message-Id: <20210412084018.489822201@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210412084016.009884719@linuxfoundation.org> References: <20210412084016.009884719@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Johannes Berg commit 1153a74768a9212daadbb50767aa400bc6a0c9b0 upstream. Normally, TXQs have txq->tid = tid; txq->ac = ieee80211_ac_from_tid(tid); However, the special management TXQ actually has txq->tid = IEEE80211_NUM_TIDS; // 16 txq->ac = IEEE80211_AC_VO; This makes sense, but ieee80211_ac_from_tid(16) is the same as ieee80211_ac_from_tid(0) which is just IEEE80211_AC_BE. Now, normally this is fine. However, if the netdev queues were stopped, then the code in ieee80211_tx_dequeue() will propagate the stop from the interface (vif->txqs_stopped[]) if the AC 2 (ieee80211_ac_from_tid(txq->tid)) is marked as stopped. On wake, however, __ieee80211_wake_txqs() will wake the TXQ if AC 0 (txq->ac) is woken up. If a driver stops all queues with ieee80211_stop_tx_queues() and then wakes them again with ieee80211_wake_tx_queues(), the ieee80211_wake_txqs() tasklet will run to resync queue and TXQ state. If all queues were woken, then what'll happen is that _ieee80211_wake_txqs() will run in order of HW queues 0-3, typically (and certainly for iwlwifi) corresponding to ACs 0-3, so it'll call __ieee80211_wake_txqs() for each AC in order 0-3. When __ieee80211_wake_txqs() is called for AC 0 (VO) that'll wake up the management TXQ (remember its tid is 16), and the driver's wake_tx_queue() will be called. That tries to get a frame, which will immediately *stop* the TXQ again, because now we check against AC 2, and AC 2 hasn't yet been marked as woken up again in sdata->vif.txqs_stopped[] since we're only in the __ieee80211_wake_txqs() call for AC 0. Thus, the management TXQ will never be started again. Fix this by checking txq->ac directly instead of calculating the AC as ieee80211_ac_from_tid(txq->tid). Fixes: adf8ed01e4fd ("mac80211: add an optional TXQ for other PS-buffered frames") Acked-by: Toke Høiland-Jørgensen Link: https://lore.kernel.org/r/20210323210500.bf4d50afea4a.I136ffde910486301f8818f5442e3c9bf8670a9c4@changeid Signed-off-by: Johannes Berg Signed-off-by: Greg Kroah-Hartman --- net/mac80211/tx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -3578,7 +3578,7 @@ begin: test_bit(IEEE80211_TXQ_STOP_NETIF_TX, &txqi->flags)) goto out; - if (vif->txqs_stopped[ieee80211_ac_from_tid(txq->tid)]) { + if (vif->txqs_stopped[txq->ac]) { set_bit(IEEE80211_TXQ_STOP_NETIF_TX, &txqi->flags); goto out; }