From patchwork Tue Oct 6 21:55:09 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Dmitry Torokhov X-Patchwork-Id: 11819271 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5F2721580 for ; Tue, 6 Oct 2020 21:55:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 369FB208C7 for ; Tue, 6 Oct 2020 21:55:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="E/mD8rmb" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726760AbgJFVzO (ORCPT ); Tue, 6 Oct 2020 17:55:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48006 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726759AbgJFVzO (ORCPT ); Tue, 6 Oct 2020 17:55:14 -0400 Received: from mail-pg1-x541.google.com (mail-pg1-x541.google.com [IPv6:2607:f8b0:4864:20::541]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AADA8C061755; Tue, 6 Oct 2020 14:55:13 -0700 (PDT) Received: by mail-pg1-x541.google.com with SMTP id 22so82834pgv.6; Tue, 06 Oct 2020 14:55:13 -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 :content-transfer-encoding; bh=41YT6TynwC5ufFrllX6VSGwwbv2gFzlUh+XiHKPl8Cw=; b=E/mD8rmbsDDo0cpmH1IH4aR36Q480W6RiT1EjMo0xNVCmJCrLqkyefbsVcFAPQ13wW rfp6ynKON679HDFU5wV/6U9Kzspa4gC2XrcDlm8Wr88QtINQ3b/LZC+gj8jE6Zpb9ZZW Gm9pFXYJOEIftZ+rXnxLlxWa0kJDsMxEuv6gFmUUDrHRY5RtQ0pSyDwLQHCYw1ge8q6D gEtoBFyo9tpOjtAR935+wSy+zRHM9Y4yf9Na3O2rTcPMvH2DlMJUxZ4+cVaGvkvW86dI eOIOenLZrUQ9bGrIWIYth6HNzmvbJYkWERKz98YDguzDrLpF16MWQhqQKo4MG7UrBpP9 JLlg== 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:content-transfer-encoding; bh=41YT6TynwC5ufFrllX6VSGwwbv2gFzlUh+XiHKPl8Cw=; b=negntRDU7oPY5/8C0Y3kbIJSfswdcQKVkgZYnCG00HgxCPDG9MohDNSETKu0qh8XKu RwiKOMBFWg+RCVwPM0AW37iVmHnxx2zlOv6yCvMoIVWhfbI992mlkZNlh3fI/8IzyVzU Dn6ip33EdBbsRRPQhHQYwkxqhrkWfqq6iXZWQ3Q1fv7cWTUvn+kXhOfmdqHwvAHqTJJ1 yL/I4gQnVlDGWEmePPz+MjO6mEJejaWbLT+YO9iaBXbo33vrp31KAFbpJEIw/7w4YxhR BjE6H8XeAxT5A9a5ZU5ROqyEtGJsMNV34zvM0E6hqgaGCpK2QJ008t6cQjxpe0hkl++t zIdA== X-Gm-Message-State: AOAM531fLSwaxrwj1sLULGQfobXNZqTFDwFWZUF9ZdhmENnCHVNRl2+H ayXNmcW7gZbUHckDXqTtU3w= X-Google-Smtp-Source: ABdhPJzpyBKLQjvXEkHl4oYJaVQUu5wfHAeN9KmD8z/Sqd3e/fEN1+fU+i4L5I0H2iYxucDQe9nn0g== X-Received: by 2002:a62:7749:0:b029:152:9d3b:c85e with SMTP id s70-20020a6277490000b02901529d3bc85emr35858pfc.16.1602021313034; Tue, 06 Oct 2020 14:55:13 -0700 (PDT) Received: from dtor-ws ([2620:15c:202:201:a6ae:11ff:fe11:fcc3]) by smtp.gmail.com with ESMTPSA id c67sm148242pfa.209.2020.10.06.14.55.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 06 Oct 2020 14:55:12 -0700 (PDT) Date: Tue, 6 Oct 2020 14:55:09 -0700 From: dmitry.torokhov@gmail.com To: Jonathan Cameron Cc: Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler , Kukjin Kim , Krzysztof Kozlowski , Andrzej Pietrasiewicz , =?utf-8?b?TWljaGHFgiBNaXJv?= =?utf-8?b?c8WCYXc=?= , linux-iio@vger.kernel.org, linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3] iio: adc: exynos: do not rely on 'users' counter in ISR Message-ID: <20201006215509.GA2556081@dtor-ws> MIME-Version: 1.0 Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org The order in which 'users' counter is decremented vs calling drivers' close() method is implementation specific, and we should not rely on it. Let's introduce driver private flag and use it to signal ISR to exit when device is being closed. This has a side-effect of fixing issue of accessing inut->users outside of input->mutex protection. Reported-by: Andrzej Pietrasiewicz Acked-by: Krzysztof Kozlowski Reviewed-by: Michał Mirosław Signed-off-by: Dmitry Torokhov --- v3: fixed typo in exynos_adc_ts_close() per Michał Mirosław v2: switched from ordinary read/write to READ_ONCE/WRITE_ONCE per Michał Mirosław drivers/iio/adc/exynos_adc.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/iio/adc/exynos_adc.c b/drivers/iio/adc/exynos_adc.c index 22131a677445..908df4b9b93c 100644 --- a/drivers/iio/adc/exynos_adc.c +++ b/drivers/iio/adc/exynos_adc.c @@ -7,6 +7,7 @@ * Copyright (C) 2013 Naveen Krishna Chatradhi */ +#include #include #include #include @@ -135,6 +136,8 @@ struct exynos_adc { u32 value; unsigned int version; + bool ts_enabled; + bool read_ts; u32 ts_x; u32 ts_y; @@ -633,7 +636,7 @@ static irqreturn_t exynos_ts_isr(int irq, void *dev_id) bool pressed; int ret; - while (info->input->users) { + while (READ_ONCE(info->ts_enabled)) { ret = exynos_read_s3c64xx_ts(dev, &x, &y); if (ret == -ETIMEDOUT) break; @@ -712,6 +715,7 @@ static int exynos_adc_ts_open(struct input_dev *dev) { struct exynos_adc *info = input_get_drvdata(dev); + WRITE_ONCE(info->ts_enabled, true); enable_irq(info->tsirq); return 0; @@ -721,6 +725,7 @@ static void exynos_adc_ts_close(struct input_dev *dev) { struct exynos_adc *info = input_get_drvdata(dev); + WRITE_ONCE(info->ts_enabled, false); disable_irq(info->tsirq); }