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=-8.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 75B7EC18E5B for ; Mon, 16 Mar 2020 12:50:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4F86420658 for ; Mon, 16 Mar 2020 12:50:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="BIgHvYml" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731105AbgCPMuM (ORCPT ); Mon, 16 Mar 2020 08:50:12 -0400 Received: from mail-pg1-f194.google.com ([209.85.215.194]:40053 "EHLO mail-pg1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730970AbgCPMuM (ORCPT ); Mon, 16 Mar 2020 08:50:12 -0400 Received: by mail-pg1-f194.google.com with SMTP id t24so9696868pgj.7; Mon, 16 Mar 2020 05:50:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:mime-version:content-disposition :user-agent; bh=yQQRBR3UCe1qFAx8WTjG74chuD0+CqzV1dqAc0ruQoA=; b=BIgHvYmlSE6AOKfBu9BXFcE/GbdLe5qPUTNF7It4xxB7VJ3yOfWCFmZ4EQIuqykMdX Wp/wojkEkcSsF5KmMCLYoiJaSqEnQaAPxehCyF+dod/K9ulofLfsaMZHQP8TeULL/7iT M51UUcMgH8TUWXrNR8mW0AlRRBluT5y0LE5zkKWJ0GKG1PVHMDjhwlBhp4DPkeFw4F3Q K9x7qOMM7y6tXrXeqI/vEv/i/qmldjytstAz5zZGcIIRBfumb4S8hWcMML/MiKlPYumV +nYOQnkEr3uCFFlwjy6wx60iHwnaCNG61uKXePEQ7k0Px4W9gNhEQKUWaQp1uxf7nO/G U7kA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:mime-version :content-disposition:user-agent; bh=yQQRBR3UCe1qFAx8WTjG74chuD0+CqzV1dqAc0ruQoA=; b=uM32O9hqR3AG61poIlpTynWWQ1sDvXt+v4c/KCW5srr7hbdL/l2Zy/9p06F8ny7vbk zttSP/rrLaS4/87uJRCBWfBhxirwBg7JNymMH/yEIlmxzYEbooRwJ4yLD1VQyXhf1SEE sS34fR97cFwxWkvOMf9eU29FWy3KXYf+HjtB2QlIUj/dS+pZ+oluBuscNe6SsA4TQv0K L89qPMUbmxjHlik4Gkeglic0BMrOY4yodWuXY3Rp5DJMqI1NTju2fsbsS8aSHg3SP9Tb PTvxorSDaTsm1WliUKLpWpWEntNPnWnV0+ou3Pi6WOEzmqDUiywj89SDsCc+rYmg6HGn KDlw== X-Gm-Message-State: ANhLgQ0Kr0NVlzKvbkZsXpjA75ouf8ssnZtHTpAx7EaA2g6+q8jsxZ9q vwt3llmLlWiBawIg46gC2i8= X-Google-Smtp-Source: ADFU+vtvHKaZuwCfss780zR+3XbBpQD+Epnuh5nt9MyiUc0PzY16d5ELEBghO9Cr/SzGtJzKK+CoFw== X-Received: by 2002:a63:2:: with SMTP id 2mr26113109pga.102.1584363011205; Mon, 16 Mar 2020 05:50:11 -0700 (PDT) Received: from syed.domain.name ([103.201.127.108]) by smtp.gmail.com with ESMTPSA id x18sm55976328pfo.148.2020.03.16.05.50.08 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 16 Mar 2020 05:50:10 -0700 (PDT) Date: Mon, 16 Mar 2020 18:20:06 +0530 From: Syed Nayyar Waris To: vilhelm.gray@gmail.com Cc: jic23@kernel.org, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v5 2/3] counter: 104-quad-8: Add lock guards - differential encoder Message-ID: <20200316125006.GA415@syed.domain.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add lock protection from race conditions to 104-quad-8 counter driver for differential encoder status code changes. Mutex lock calls used for protection. Signed-off-by: Syed Nayyar Waris --- Changes in v5: - Change spin lock calls to mutex lock calls. - Modify the title description. drivers/counter/104-quad-8.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c index 9dab190..21b2e3e 100644 --- a/drivers/counter/104-quad-8.c +++ b/drivers/counter/104-quad-8.c @@ -1151,18 +1151,26 @@ static ssize_t quad8_signal_cable_fault_read(struct counter_device *counter, struct counter_signal *signal, void *private, char *buf) { - const struct quad8_iio *const priv = counter->priv; + struct quad8_iio *const priv = counter->priv; const size_t channel_id = signal->id / 2; - const bool disabled = !(priv->cable_fault_enable & BIT(channel_id)); + bool disabled; unsigned int status; unsigned int fault; - if (disabled) + mutex_lock(&priv->lock); + + disabled = !(priv->cable_fault_enable & BIT(channel_id)); + + if (disabled) { + mutex_unlock(&priv->lock); return -EINVAL; + } /* Logic 0 = cable fault */ status = inb(priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS); + mutex_unlock(&priv->lock); + /* Mask respective channel and invert logic */ fault = !(status & BIT(channel_id)); @@ -1194,6 +1202,8 @@ static ssize_t quad8_signal_cable_fault_enable_write( if (ret) return ret; + mutex_lock(&priv->lock); + if (enable) priv->cable_fault_enable |= BIT(channel_id); else @@ -1204,6 +1214,8 @@ static ssize_t quad8_signal_cable_fault_enable_write( outb(cable_fault_enable, priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS); + mutex_unlock(&priv->lock); + return len; } -- 2.7.4