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=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,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 9558AC10F06 for ; Wed, 27 Mar 2019 18:42:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6866C2082F for ; Wed, 27 Mar 2019 18:42:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553712138; bh=ks2YUMp0EyQpEs3Ow1PHCEffpB9rW8iO8XuspyGU/Jw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=jwZeeD/L+uTck0om6oO4y52g3JBSTQ8KhBLfD9dJu1cdbHjxvNLZ7S0rT9Ws+rwTE x2bWX7NBvZODxZbxogrYgNlXqIVsmpD053Hni2P7zIARCNcI++3//nvHnmTXulmApK 5q8FO6E9VHloKyEA3k4z5PDqk6SJ5ox3rQFPOVFc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403796AbfC0SWA (ORCPT ); Wed, 27 Mar 2019 14:22:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:39966 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2403782AbfC0SV7 (ORCPT ); Wed, 27 Mar 2019 14:21:59 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D6CF620643; Wed, 27 Mar 2019 18:21:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553710918; bh=ks2YUMp0EyQpEs3Ow1PHCEffpB9rW8iO8XuspyGU/Jw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=inkKAhDrh/9Q5iJlc1STDmdW47o7SPKprgTAJnouqOTRMibk3qU1QPg/UvXuTcrFH rAvqyXvmac0JxlTWwMmpA7ju8tCFPKZdiqLH2DWRAyOABcCmcHYx7WD69rSrps9FVg u9ssViHJZhb1tNN7oigzcjQC5uHiyGqXRm+Mw7SI= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Sara Sharon , Luca Coelho , Sasha Levin , linux-wireless@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.9 46/87] iwlwifi: pcie: fix emergency path Date: Wed, 27 Mar 2019 14:19:59 -0400 Message-Id: <20190327182040.17444-46-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190327182040.17444-1-sashal@kernel.org> References: <20190327182040.17444-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org From: Sara Sharon [ 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 e58a50d31d96..c21f8bd32d08 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