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=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 918EFC6786F for ; Tue, 30 Oct 2018 09:31:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 64E8F20831 for ; Tue, 30 Oct 2018 09:31:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 64E8F20831 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linutronix.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727427AbeJ3SYh (ORCPT ); Tue, 30 Oct 2018 14:24:37 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:53435 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726212AbeJ3SYh (ORCPT ); Tue, 30 Oct 2018 14:24:37 -0400 Received: from hsi-kbw-5-158-153-52.hsi19.kabel-badenwuerttemberg.de ([5.158.153.52] helo=kurt.tec.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.80) (envelope-from ) id 1gHQNB-0003Lk-UV; Tue, 30 Oct 2018 10:31:42 +0100 From: Kurt Kanzenbach To: Anirudha Sarangi , John Linn , "David S. Miller" Cc: Michal Simek , Radhey Shyam Pandey , Andrew Lunn , YueHaibing , netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Kurt Kanzenbach Subject: [PATCH 2/2] net: xilinx_emaclite: recheck condition after timeout in mdio_wait() Date: Tue, 30 Oct 2018 10:31:39 +0100 Message-Id: <20181030093139.10226-3-kurt@linutronix.de> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20181030093139.10226-1-kurt@linutronix.de> References: <20181030093139.10226-1-kurt@linutronix.de> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The function could report a false positive if it gets preempted between reading the XEL_MDIOCTRL_OFFSET register and checking for the timeout. In such a case, the condition has to be rechecked to avoid false positives. Therefore, check for expected condition even after the timeout occurred. Signed-off-by: Kurt Kanzenbach --- drivers/net/ethernet/xilinx/xilinx_emaclite.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/drivers/net/ethernet/xilinx/xilinx_emaclite.c b/drivers/net/ethernet/xilinx/xilinx_emaclite.c index 639e3e99af46..957d03085bd0 100644 --- a/drivers/net/ethernet/xilinx/xilinx_emaclite.c +++ b/drivers/net/ethernet/xilinx/xilinx_emaclite.c @@ -714,19 +714,29 @@ static irqreturn_t xemaclite_interrupt(int irq, void *dev_id) static int xemaclite_mdio_wait(struct net_local *lp) { unsigned long end = jiffies + 2; + u32 val; /* wait for the MDIO interface to not be busy or timeout * after some time. */ - while (xemaclite_readl(lp->base_addr + XEL_MDIOCTRL_OFFSET) & - XEL_MDIOCTRL_MDIOSTS_MASK) { + while (1) { + val = xemaclite_readl(lp->base_addr + XEL_MDIOCTRL_OFFSET); + + if (!(val & XEL_MDIOCTRL_MDIOSTS_MASK)) + return 0; + if (time_before_eq(end, jiffies)) { - WARN_ON(1); - return -ETIMEDOUT; + val = xemaclite_readl(lp->base_addr + XEL_MDIOCTRL_OFFSET); + break; } + msleep(1); } - return 0; + if (!(val & XEL_MDIOCTRL_MDIOSTS_MASK)) + return 0; + + WARN_ON(1); + return -ETIMEDOUT; } /** -- 2.11.0