From patchwork Tue May 8 08:26:38 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sekhar Nori X-Patchwork-Id: 135134 Delivered-To: patch@linaro.org Received: by 10.46.151.6 with SMTP id r6csp4106397lji; Tue, 8 May 2018 01:26:53 -0700 (PDT) X-Google-Smtp-Source: AB8JxZqzTidYPZ24ocb+96fqgqBKB0LekI50JUDJ6fj+bDpjLym25u90W5ylIsWC7tHddbwuSinr X-Received: by 2002:a17:902:bc4a:: with SMTP id t10-v6mr40648667plz.343.1525768013579; Tue, 08 May 2018 01:26:53 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1525768013; cv=none; d=google.com; s=arc-20160816; b=MhZLiczsWWiszaOz5sjaP6li3B+IKNSroj1pRGvTmdmxJXgwlKHDsjLfJN7ys0VEZc +QEXW09JSQiu52if2zVLGWhsyUr7JVYk7TAATYnVVn6uBEWbWarUuYPtBzVaZCTS3dUW JwX65DM/Fiw3jd03n+XWYlq13ljoKQN3qpknmt5WvNgs6PI5L8HLTymUzED+tnVN0XpJ UVqeG0JcRHkzT9zYMlnDUqxukYSL5hy3+RW04PEsJDIynbxX0Zu/Irrmb0drSEbiFS43 SMkEVojd0GXOKCzL9lxh1c5YWzCBsKebKwvliueb9XlUbZM2WJQM24ChSaCxS6KvmA4J SgZA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:mime-version:message-id:date:subject:cc :to:from:dkim-signature:arc-authentication-results; bh=yUo+9B7ds018eEHZY9Yy0o01G1yn1RhoqYNLpsDzcjI=; b=st6+SvCHW01LkEdgP43+gsA/+/89wEd3hqywCbzW2rQKtut0ph/p+zjvxQV853fHgU ycskGD/1xpyzgdi9bT7XBOFbrSHSJFlMw/+5rpgQ47SQNsfrBrhUnS9FPQoeEU7igqf4 tVO5qHnMepN0ImHJt54wNCmu6Mvb4QRTqFu3+Th+Fir2c3zDyo4Y/FFMomWb24+Yd+Jz 6EHm3B46WXT+4Q0tZ5kYuQFEpKmP7i7QWSBVg8wiXsaQhw7zAUhrpiNfffnPTdDlf+Da OYHwgC7BIPpBYyhwr8c1Sdyw82F0rSFH9ZqIa+wvsX6C+Ex6ikuBWkZxNz1v3uFfd5u9 5kqg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@ti.com header.s=ti-com-17Q1 header.b=O1Uci68i; spf=pass (google.com: best guess record for domain of netdev-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=netdev-owner@vger.kernel.org; dmarc=pass (p=QUARANTINE sp=NONE dis=NONE) header.from=ti.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id m1-v6si22757763plt.276.2018.05.08.01.26.53; Tue, 08 May 2018 01:26:53 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of netdev-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@ti.com header.s=ti-com-17Q1 header.b=O1Uci68i; spf=pass (google.com: best guess record for domain of netdev-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=netdev-owner@vger.kernel.org; dmarc=pass (p=QUARANTINE sp=NONE dis=NONE) header.from=ti.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754809AbeEHI0u (ORCPT + 9 others); Tue, 8 May 2018 04:26:50 -0400 Received: from lelnx194.ext.ti.com ([198.47.27.80]:42634 "EHLO lelnx194.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754795AbeEHI0q (ORCPT ); Tue, 8 May 2018 04:26:46 -0400 Received: from dflxv15.itg.ti.com ([128.247.5.124]) by lelnx194.ext.ti.com (8.15.1/8.15.1) with ESMTP id w488QgOj018067; Tue, 8 May 2018 03:26:42 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1525768002; bh=yUo+9B7ds018eEHZY9Yy0o01G1yn1RhoqYNLpsDzcjI=; h=From:To:CC:Subject:Date; b=O1Uci68iInJvNoMSFegzQrnqIrlmLTC08ke5LOZaHye8XBh1xhw2xzAzFGwWh8VW/ XK5kxEanTgpLcYrNlCj4Xbt4oaQnDC7/XRWeIwpOU5tYOrv0VwtIVe1RcWtgyzrMRE dhO8gnZbhU4z5ivHYgaUdk7perVuD8JGVu+QIpQk= Received: from DFLE110.ent.ti.com (dfle110.ent.ti.com [10.64.6.31]) by dflxv15.itg.ti.com (8.14.3/8.13.8) with ESMTP id w488Qgqw008939; Tue, 8 May 2018 03:26:42 -0500 Received: from DFLE102.ent.ti.com (10.64.6.23) by DFLE110.ent.ti.com (10.64.6.31) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1466.3; Tue, 8 May 2018 03:26:41 -0500 Received: from dlep33.itg.ti.com (157.170.170.75) by DFLE102.ent.ti.com (10.64.6.23) with Microsoft SMTP Server (version=TLS1_0, cipher=TLS_RSA_WITH_AES_256_CBC_SHA) id 15.1.1466.3 via Frontend Transport; Tue, 8 May 2018 03:26:41 -0500 Received: from psplinux063.india.ti.com (ileax41-snat.itg.ti.com [10.172.224.153]) by dlep33.itg.ti.com (8.14.3/8.13.8) with ESMTP id w488Qd4Q028065; Tue, 8 May 2018 03:26:40 -0500 From: Sekhar Nori To: Grygorii Strashko CC: "David S . Miller" , , Subject: [PATCH net-next] drivers: net: davinci_mdio: prevent sprious timeout Date: Tue, 8 May 2018 13:56:38 +0530 Message-ID: <20180508082638.5707-1-nsekhar@ti.com> X-Mailer: git-send-email 2.16.2 MIME-Version: 1.0 X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org A well timed kernel preemption in the time_after() loop in wait_for_idle() can result in a spurious timeout error to be returned. Fix it by checking for status of hardware before returning timeout error. Signed-off-by: Sekhar Nori --- The issue has not been personally observed by me, but has been reported by users. Sending for next-next given the non-critical nature. There is seems to be no easy way to reproduce this. drivers/net/ethernet/ti/davinci_mdio.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) -- 2.16.2 diff --git a/drivers/net/ethernet/ti/davinci_mdio.c b/drivers/net/ethernet/ti/davinci_mdio.c index 3c33f4504d8e..4fbd04fd38cf 100644 --- a/drivers/net/ethernet/ti/davinci_mdio.c +++ b/drivers/net/ethernet/ti/davinci_mdio.c @@ -231,10 +231,16 @@ static inline int wait_for_idle(struct davinci_mdio_data *data) while (time_after(timeout, jiffies)) { if (__raw_readl(®s->control) & CONTROL_IDLE) - return 0; + goto out; } - dev_err(data->dev, "timed out waiting for idle\n"); - return -ETIMEDOUT; + + if (!(__raw_readl(®s->control) & CONTROL_IDLE)) { + dev_err(data->dev, "timed out waiting for idle\n"); + return -ETIMEDOUT; + } + +out: + return 0; } static int davinci_mdio_read(struct mii_bus *bus, int phy_id, int phy_reg)