From patchwork Tue Oct 6 04:12:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Dmitry Torokhov X-Patchwork-Id: 268004 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=-9.6 required=3.0 tests=BAYES_00,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, URIBL_BLOCKED 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 9C9D3C4363D for ; Tue, 6 Oct 2020 04:12:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 528D5208A9 for ; Tue, 6 Oct 2020 04:12:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="g1ZUY1XH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726073AbgJFEMR (ORCPT ); Tue, 6 Oct 2020 00:12:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53368 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725882AbgJFEMR (ORCPT ); Tue, 6 Oct 2020 00:12:17 -0400 Received: from mail-pg1-x544.google.com (mail-pg1-x544.google.com [IPv6:2607:f8b0:4864:20::544]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 962EFC0613CE; Mon, 5 Oct 2020 21:12:17 -0700 (PDT) Received: by mail-pg1-x544.google.com with SMTP id r10so180278pgb.10; Mon, 05 Oct 2020 21:12:17 -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=HwUCVxLaOWReGj/++nkGikV+jRyqPV3oLYh82Dlr2Zo=; b=g1ZUY1XHEAer78d/G/a+EyY3prXdEq+o+f5KAImHzibvav6awCFOgLSxxGn06PpW2c osSTFChqonvGurbT/ylDaYobheGShjwCg8tdmiZe/eAcqJo06uNNjKhv0mhgFlPc+GHh j6Y47eGgVbkVmaWGi1m3QBdss5dFS5grEq+v+SYHAgdrUJnZYVjWn1/50yciX8JWrIju LdyKZshDQHzDh445mUMkoZyimWSgVTiZC56zCo+c1ixuyrBVNdc93Igj0lWJKmqKRUS0 49VOCu9drvtSdQ6DnfLE5gPDMOswoVV8gFkF8uW8iJfsXHYdvhi2SOWy/FC3oh1VAhZQ HcAg== 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=HwUCVxLaOWReGj/++nkGikV+jRyqPV3oLYh82Dlr2Zo=; b=MqvMeFnVVoJklcAIjD+U5RcWJNxwMLKyOEVWuEE46kmDnJ6PFLoxxs0RM6ie39J05V /jNmTxswuUcAgtBW9sh6Q+SoOUr/ElY6OBD9S1O1jI2q/Q2RfvWdpkGyddS5pP+awTqh YzA3KJSStXSIZZz4bbckgVuC9l859FJNcJLNap6GyGvjVJM2STbyAe9zTQdgIwJU7N0z BzJHP2zCGlN+HnPKzhNNYa7qkuZQwPV8Ut6t7XNgGq7pixmHH9hbe97L3lKzW/Ow+UP0 27j8ECV91LEqACTy2HQjMfq2xhO2/xJLBc40R729tF3YoYEPED0YL1ScXw59VGJmuSLA W3rw== X-Gm-Message-State: AOAM533y6gPqhxwGxI78FLTy44/6m6BlYMHtdBRMtL8hz4hrwYJIk2lv GAGwqta/fp72OeekvGKNNHc= X-Google-Smtp-Source: ABdhPJzw2Ms221Zj4/SbT46oKwh5Nx3E6AfFsIONc6DxNHFPkVu+HiW5rFl53MV5hurP76A2u1y6fA== X-Received: by 2002:aa7:821a:0:b029:152:aa68:222d with SMTP id k26-20020aa7821a0000b0290152aa68222dmr2837484pfi.73.1601957536981; Mon, 05 Oct 2020 21:12:16 -0700 (PDT) Received: from dtor-ws ([2620:15c:202:201:a6ae:11ff:fe11:fcc3]) by smtp.gmail.com with ESMTPSA id b16sm1573170pfp.195.2020.10.05.21.12.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 05 Oct 2020 21:12:16 -0700 (PDT) Date: Mon, 5 Oct 2020 21:12:14 -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?q?Micha=C5=82?= =?utf-8?q?_Miros=C5=82aw?= , linux-iio@vger.kernel.org, linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] iio: adc: exynos: do not rely on 'users' counter in ISR Message-ID: <20201006041214.GA4145870@dtor-ws> MIME-Version: 1.0 Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-samsung-soc@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 Signed-off-by: Dmitry Torokhov Acked-by: Krzysztof Kozlowski Reviewed-by: 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..6c705fe599a3 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, true); disable_irq(info->tsirq); }