From patchwork Sun Feb 23 13:38:40 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marek Vasut X-Patchwork-Id: 1242677 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=denx.de Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 48QR9q4CCfz9sRG for ; Mon, 24 Feb 2020 00:38:55 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726748AbgBWNiy (ORCPT ); Sun, 23 Feb 2020 08:38:54 -0500 Received: from mail-out.m-online.net ([212.18.0.9]:41544 "EHLO mail-out.m-online.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726208AbgBWNix (ORCPT ); Sun, 23 Feb 2020 08:38:53 -0500 Received: from frontend01.mail.m-online.net (unknown [192.168.8.182]) by mail-out.m-online.net (Postfix) with ESMTP id 48QR9h6hKwz1qr4x; Sun, 23 Feb 2020 14:38:45 +0100 (CET) Received: from localhost (dynscan1.mnet-online.de [192.168.6.70]) by mail.m-online.net (Postfix) with ESMTP id 48QR9d6J5Rz1r0cN; Sun, 23 Feb 2020 14:38:45 +0100 (CET) X-Virus-Scanned: amavisd-new at mnet-online.de Received: from mail.mnet-online.de ([192.168.8.182]) by localhost (dynscan1.mail.m-online.net [192.168.6.70]) (amavisd-new, port 10024) with ESMTP id ebCWh7-Rq8qo; Sun, 23 Feb 2020 14:38:44 +0100 (CET) X-Auth-Info: /jqsAtzJ2fVC8MNoLiaDRBNeyneHjPfDMUL6E1+yjqc= Received: from desktop.lan (ip-86-49-35-8.net.upcbroadband.cz [86.49.35.8]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.mnet-online.de (Postfix) with ESMTPSA; Sun, 23 Feb 2020 14:38:44 +0100 (CET) From: Marek Vasut To: netdev@vger.kernel.org Cc: Marek Vasut , "David S . Miller" , Lukas Wunner , Petr Stetiar , YueHaibing Subject: [PATCH] net: ks8851-ml: Fix IRQ handling and locking Date: Sun, 23 Feb 2020 14:38:40 +0100 Message-Id: <20200223133840.318025-1-marex@denx.de> X-Mailer: git-send-email 2.25.0 MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The KS8851 requires that packet RX and TX are mutually exclusive. Currently, the driver hopes to achieve this by disabling interrupt from the card by writing the card registers and by disabling the interrupt on the interrupt controller. This however is racy on SMP. Replace this approach by expanding the spinlock used around the ks_start_xmit() TX path to ks_irq() RX path to assure true mutual exclusion and remove the interrupt enabling/disabling, which is now not needed anymore. Furthermore, disable interrupts also in ks_net_stop(), which was missing before. Note that a massive improvement here would be to re-use the KS8851 driver approach, which is to move the TX path into a worker thread, interrupt handling to threaded interrupt, and synchronize everything with mutexes, but that would be a much bigger rework, for a separate patch. Signed-off-by: Marek Vasut Cc: David S. Miller Cc: Lukas Wunner Cc: Petr Stetiar Cc: YueHaibing --- drivers/net/ethernet/micrel/ks8851_mll.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/drivers/net/ethernet/micrel/ks8851_mll.c b/drivers/net/ethernet/micrel/ks8851_mll.c index 1c9e70c8cc30..58579baf3f7a 100644 --- a/drivers/net/ethernet/micrel/ks8851_mll.c +++ b/drivers/net/ethernet/micrel/ks8851_mll.c @@ -513,14 +513,17 @@ static irqreturn_t ks_irq(int irq, void *pw) { struct net_device *netdev = pw; struct ks_net *ks = netdev_priv(netdev); + unsigned long flags; u16 status; + spin_lock_irqsave(&ks->statelock, flags); /*this should be the first in IRQ handler */ ks_save_cmd_reg(ks); status = ks_rdreg16(ks, KS_ISR); if (unlikely(!status)) { ks_restore_cmd_reg(ks); + spin_unlock_irqrestore(&ks->statelock, flags); return IRQ_NONE; } @@ -546,6 +549,7 @@ static irqreturn_t ks_irq(int irq, void *pw) ks->netdev->stats.rx_over_errors++; /* this should be the last in IRQ handler*/ ks_restore_cmd_reg(ks); + spin_unlock_irqrestore(&ks->statelock, flags); return IRQ_HANDLED; } @@ -615,6 +619,7 @@ static int ks_net_stop(struct net_device *netdev) /* shutdown RX/TX QMU */ ks_disable_qmu(ks); + ks_disable_int(ks); /* set powermode to soft power down to save power */ ks_set_powermode(ks, PMECR_PM_SOFTDOWN); @@ -671,10 +676,9 @@ static netdev_tx_t ks_start_xmit(struct sk_buff *skb, struct net_device *netdev) { netdev_tx_t retv = NETDEV_TX_OK; struct ks_net *ks = netdev_priv(netdev); + unsigned long flags; - disable_irq(netdev->irq); - ks_disable_int(ks); - spin_lock(&ks->statelock); + spin_lock_irqsave(&ks->statelock, flags); /* Extra space are required: * 4 byte for alignment, 4 for status/length, 4 for CRC @@ -688,9 +692,7 @@ static netdev_tx_t ks_start_xmit(struct sk_buff *skb, struct net_device *netdev) dev_kfree_skb(skb); } else retv = NETDEV_TX_BUSY; - spin_unlock(&ks->statelock); - ks_enable_int(ks); - enable_irq(netdev->irq); + spin_unlock_irqrestore(&ks->statelock, flags); return retv; }