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=-9.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 85FCFC10F0E for ; Thu, 4 Apr 2019 09:48:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 570EA206B7 for ; Thu, 4 Apr 2019 09:48:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554371318; bh=of87jsM+rHuEVl0svtfaTXlFdX9tnwNNu0werUnqz/c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=XAkvVz2fdepX6sdZ8e2e3qrYtfTsjcGG6HnALYcHhsUl6eo9sXpVkaYl3LpEEzavo z8/8IZqni28uDXijuA2TyrAZszQKun8l9BhkzqUYWn8INVdEEJEfJMJNrHur0hq3rw f2sWMcWRiQzIGFVRGNCT+qXWZaYOynmXEdu6N5e4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730636AbfDDI5L (ORCPT ); Thu, 4 Apr 2019 04:57:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:60720 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730614AbfDDI5G (ORCPT ); Thu, 4 Apr 2019 04:57:06 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C7DC72177E; Thu, 4 Apr 2019 08:57:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554368225; bh=of87jsM+rHuEVl0svtfaTXlFdX9tnwNNu0werUnqz/c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=l1J+fh6McxFBFpRFQoyvQLwQH7IbpaMHurIROt0xpj+P17ZMqnGef5kW9kGBfeoWN hmmXGC+uaNsy4vq0MsOqACVf1HRZGhzC3evKXMFK/JtAnuTjLiEkv0JJfSf7LaqRrK 5GBAaZtD9QbtI7rGGmKg3YVvwvWB/gBCD+oegx5M= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ilan Peer , Sara Sharon , Luca Coelho , Sasha Levin Subject: [PATCH 4.14 068/121] iwlwifi: pcie: fix emergency path Date: Thu, 4 Apr 2019 10:47:36 +0200 Message-Id: <20190404084548.959197639@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190404084545.245659903@linuxfoundation.org> References: <20190404084545.245659903@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit c6ac9f9fb98851f47b978a9476594fc3c477a34d ] Allocator swaps the pending requests with 0 when it starts working. This means that relying on it n RX path to decide if to move to emergency is not always a good idea, since it may be zero, but there are still a lot of unallocated RBs in the system. Change allocator to decrement the pending requests on real time. It is more expensive since it accesses the atomic variable more times, but it gives the RX path a better idea of the system's status. Reported-by: Ilan Peer Signed-off-by: Sara Sharon Fixes: 868a1e863f95 ("iwlwifi: pcie: avoid empty free RB queue") Signed-off-by: Luca Coelho Signed-off-by: Sasha Levin --- drivers/net/wireless/intel/iwlwifi/pcie/rx.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c index 5a15362ef671..a40ad4675e19 100644 --- a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c +++ b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c @@ -475,7 +475,7 @@ static void iwl_pcie_rx_allocator(struct iwl_trans *trans) struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans); struct iwl_rb_allocator *rba = &trans_pcie->rba; struct list_head local_empty; - int pending = atomic_xchg(&rba->req_pending, 0); + int pending = atomic_read(&rba->req_pending); IWL_DEBUG_RX(trans, "Pending allocation requests = %d\n", pending); @@ -530,11 +530,13 @@ static void iwl_pcie_rx_allocator(struct iwl_trans *trans) i++; } + atomic_dec(&rba->req_pending); pending--; + if (!pending) { - pending = atomic_xchg(&rba->req_pending, 0); + pending = atomic_read(&rba->req_pending); IWL_DEBUG_RX(trans, - "Pending allocation requests = %d\n", + "Got more pending allocation requests = %d\n", pending); } @@ -546,12 +548,15 @@ static void iwl_pcie_rx_allocator(struct iwl_trans *trans) spin_unlock(&rba->lock); atomic_inc(&rba->req_ready); + } spin_lock(&rba->lock); /* return unused rbds to the allocator empty list */ list_splice_tail(&local_empty, &rba->rbd_empty); spin_unlock(&rba->lock); + + IWL_DEBUG_RX(trans, "%s, exit.\n", __func__); } /* -- 2.19.1