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 138C5C433F5 for ; Tue, 18 Jan 2022 03:36:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235748AbiARDgA (ORCPT ); Mon, 17 Jan 2022 22:36:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44996 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353473AbiARDdF (ORCPT ); Mon, 17 Jan 2022 22:33:05 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 47FD7C037005; Mon, 17 Jan 2022 19:08:59 -0800 (PST) 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 DACA860BC5; Tue, 18 Jan 2022 03:08:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id ED9ABC36AEB; Tue, 18 Jan 2022 03:08:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1642475338; bh=x0GDq5/TGahdJpi0k1BZhKdPLlEVphD7FM3LYcMZxcg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VO2/kE4vWzapmNvQSJEzdrvsXSFNEh90pW7IfPSvVtYK2h2BMk2fI8kiTTvogATYv sCkMs+BzYSD4DvHZpfQe2x4c9b5tI/MbXBGGXzx8IhJAKltWjM1jaGuyXrfvrqvpMg c9l1bezs2xxKEsgE37mdR2EJmZbDxBvJgK6p92qcn8CLR6Un2pi1HcsiiYtqWyqbQ5 +XR1m+/bD6PJFzxththNDoajxBMpLHaq0/ZDfsdAHR6l5zSBM9LItXJkIkqBeasVpN Rd2aRIy5M9/kWobeXeHC7eszTsiSnxryWVBzYNCeh72jMK9bt4H5B0Fh1HgyuFGftD d1EtUHjn6otlQ== 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, linux-wireless@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.4 12/29] iwlwifi: mvm: synchronize with FW after multicast commands Date: Mon, 17 Jan 2022 22:08:05 -0500 Message-Id: <20220118030822.1955469-12-sashal@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220118030822.1955469-1-sashal@kernel.org> References: <20220118030822.1955469-1-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: linux-wireless@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 --- drivers/net/wireless/iwlwifi/mvm/mac80211.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/drivers/net/wireless/iwlwifi/mvm/mac80211.c b/drivers/net/wireless/iwlwifi/mvm/mac80211.c index ca498b1f1f568..6417fda88733c 100644 --- a/drivers/net/wireless/iwlwifi/mvm/mac80211.c +++ b/drivers/net/wireless/iwlwifi/mvm/mac80211.c @@ -1957,6 +1957,7 @@ 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); @@ -1966,6 +1967,22 @@ 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