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 3A229C433FE for ; Tue, 18 Jan 2022 02:27:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244815AbiARC1H (ORCPT ); Mon, 17 Jan 2022 21:27:07 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:41760 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244839AbiARCZD (ORCPT ); Mon, 17 Jan 2022 21:25:03 -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 54C3160C89; Tue, 18 Jan 2022 02:25:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4E9A3C36AE3; Tue, 18 Jan 2022 02:25:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1642472702; bh=02LVYUDW/mrOuwuMTZ8bCkojsOTTzLhDWhfOpPkpTUw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QQHUmlFokZfzJe+mTsad4Yhw6ptWSoNjewMdQPFWVuYbBKdOYkpdfzkcmc1oHYhuE H+y6JEGeWS1y7zqJkGSkLa+62iIgtsBVif++lGrex94r/+5mG776jmtb47TWCWLoLE YAqBF0hIB9RO+HKz2dEVHrbC3Tht0M4Jg+VFuxW/fE3vOOY/vqhmAwoDPM8JBJzo11 1Lh9+ZugPvx+Aa1F+blcrdIOAHZg3jbmKj/84TqForRiAl0n2sqoTh0IxjvrSkVNJ5 O48+KnYuoZwQ58vDvQuWpvZ2NmRHuXwunsRwI4UoJ68Q35TGhiconFAXymZWGw5yZr 9rRhzcneo3dGg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Johannes Berg , Emmanuel Grumbach , Maximilian Ernestus , Luca Coelho , Sasha Levin , kvalo@kernel.org, davem@davemloft.net, kuba@kernel.org, mordechay.goodstein@intel.com, miriam.rachel.korenblit@intel.com, linux-wireless@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 5.16 104/217] iwlwifi: mvm: synchronize with FW after multicast commands Date: Mon, 17 Jan 2022 21:17:47 -0500 Message-Id: <20220118021940.1942199-104-sashal@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220118021940.1942199-1-sashal@kernel.org> References: <20220118021940.1942199-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@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 897e3b91ddb2f..9c5c10908f013 100644 --- a/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c +++ b/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c @@ -1688,6 +1688,7 @@ 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); @@ -1697,6 +1698,22 @@ 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