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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 59457C35278 for ; Mon, 24 Jan 2022 19:26:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344639AbiAXT0f (ORCPT ); Mon, 24 Jan 2022 14:26:35 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:48160 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345146AbiAXTTP (ORCPT ); Mon, 24 Jan 2022 14:19:15 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 733B5613F9; Mon, 24 Jan 2022 19:19:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 33B96C340E7; Mon, 24 Jan 2022 19:19:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643051954; bh=ZC36WnheV32GTiyfyRTPvOOYO8m2u9dH7wQLkkmFlDE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uHD7JqthSUlMrvY0v2OgWryxBX4iWjgO2iU851RHcAjIDjUv08QNxrWJlJU4hTFVP 24ce2D684VdFIi1im3d+kDqNQ/zzR4IJyXHLH5ZWibi+fb07XCLXR2qzTGdqj/PF4q wuMaaP7LPhpq63aK1JNiniBipFKkw3k2oQLgCK58= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Emmanuel Grumbach , Maximilian Ernestus , Johannes Berg , Luca Coelho , Sasha Levin Subject: [PATCH 4.19 139/239] iwlwifi: mvm: synchronize with FW after multicast commands Date: Mon, 24 Jan 2022 19:42:57 +0100 Message-Id: <20220124183947.527614489@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220124183943.102762895@linuxfoundation.org> References: <20220124183943.102762895@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 [ Upstream commit db66abeea3aefed481391ecc564fb7b7fb31d742 ] If userspace installs a lot of multicast groups very quickly, then we may run out of command queue space as we send the updates in an asynchronous fashion (due to locking concerns), and the CPU can create them faster than the firmware can process them. This is true even when mac80211 has a work struct that gets scheduled. Fix this by synchronizing with the firmware after sending all those commands - outside of the iteration we can send a synchronous echo command that just has the effect of the CPU waiting for the prior asynchronous commands to finish. This also will cause fewer of the commands to be sent to the firmware overall, because the work will only run once when rescheduled multiple times while it's running. Link: https://bugzilla.kernel.org/show_bug.cgi?id=213649 Suggested-by: Emmanuel Grumbach Reported-by: Maximilian Ernestus Signed-off-by: Johannes Berg Signed-off-by: Luca Coelho Link: https://lore.kernel.org/r/iwlwifi.20211204083238.51aea5b79ea4.I88a44798efda16e9fe480fb3e94224931d311b29@changeid Signed-off-by: Luca Coelho Signed-off-by: Sasha Levin --- .../net/wireless/intel/iwlwifi/mvm/mac80211.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c b/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c index 697a66acba9ce..3f37fb64e71c2 100644 --- a/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c +++ b/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c @@ -1623,6 +1623,7 @@ static void iwl_mvm_recalc_multicast(struct iwl_mvm *mvm) struct iwl_mvm_mc_iter_data iter_data = { .mvm = mvm, }; + int ret; lockdep_assert_held(&mvm->mutex); @@ -1632,6 +1633,22 @@ static void iwl_mvm_recalc_multicast(struct iwl_mvm *mvm) ieee80211_iterate_active_interfaces_atomic( mvm->hw, IEEE80211_IFACE_ITER_NORMAL, iwl_mvm_mc_iface_iterator, &iter_data); + + /* + * Send a (synchronous) ech command so that we wait for the + * multiple asynchronous MCAST_FILTER_CMD commands sent by + * the interface iterator. Otherwise, we might get here over + * and over again (by userspace just sending a lot of these) + * and the CPU can send them faster than the firmware can + * process them. + * Note that the CPU is still faster - but with this we'll + * actually send fewer commands overall because the CPU will + * not schedule the work in mac80211 as frequently if it's + * still running when rescheduled (possibly multiple times). + */ + ret = iwl_mvm_send_cmd_pdu(mvm, ECHO_CMD, 0, 0, NULL); + if (ret) + IWL_ERR(mvm, "Failed to synchronize multicast groups update\n"); } static u64 iwl_mvm_prepare_multicast(struct ieee80211_hw *hw, -- 2.34.1