From patchwork Fri Mar 22 17:30:52 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bartosz Golaszewski X-Patchwork-Id: 1061447 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-gpio-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=bgdev.pl Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=bgdev-pl.20150623.gappssmtp.com header.i=@bgdev-pl.20150623.gappssmtp.com header.b="LoexckY1"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 44QrKb5cf0z9sR5 for ; Sat, 23 Mar 2019 04:30:59 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728217AbfCVRa6 (ORCPT ); Fri, 22 Mar 2019 13:30:58 -0400 Received: from mail-wr1-f67.google.com ([209.85.221.67]:42679 "EHLO mail-wr1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728203AbfCVRa6 (ORCPT ); Fri, 22 Mar 2019 13:30:58 -0400 Received: by mail-wr1-f67.google.com with SMTP id g3so3217782wrx.9 for ; Fri, 22 Mar 2019 10:30:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bgdev-pl.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=n4+h1AwiYWbcvCo2SVfEpk4VI/pUxMw43QNPM3T3NW0=; b=LoexckY1HPl6LUnZOzO7JF9845wgvNJsudAL0VUzOp2BQpHgi3RUA3UrI5RyQ0PCI5 pOBbLsyCX0RWHbXqshAbxggD4RRnf5D8LOeguN9cBEkBhwi1pAvAFslfk7OWzzSvfvzw 348Q7XsI1YSJi6bTMBt/XucjxoEqtjjOqpmpQJNUfTt1hBapSfhz/PlpmrgcUiWSvNxd bnmKGJpJaJ7DHEpxgiIG2T9I6j4wkp4LlTcjPzhDbgAOsXBoeEROvaTKVytpcAvAwONR /SN2VY6cqmaiQsoDmZ2J8HC+Be/uDtuJvFK6DNjVMYXJOwHdecALA3dAYN5FdPkbyOEz gmNg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=n4+h1AwiYWbcvCo2SVfEpk4VI/pUxMw43QNPM3T3NW0=; b=Lvmwh7Y90vTyJnEojMJfi2VEwai/yDE1IxriKIr3/IvF/ckNHTs4jwhtepLPtCUDnw wXCc5iJBWhlUFO+4QHFRNuQcf0FBiMOTgdEnxcX0XlFE/dTuGkFKGeSyQkVi7itGaJHd ydXReoyaV22AvkCkGm7C4gdNZuqI5UwBt+xcV7h+vcbNP6alOhJfTMJezHfqbT8VcXkT aEfgMiSaYthhI+TtkGJMVtOlokjNMjuQMRqM4FzHgBPphjuw+mIsKQfc6fFe8RH814jj 0jrbP1eYIyVbPP1hkwVYnTUSOcEnqHX78lxm8zGjERqnnsa31lig/L+5q1ExrEvdoINx 1ZwA== X-Gm-Message-State: APjAAAVxORawQU0WXhbZQgTQcl1T9R/YMXge2kkMtIrY269NjCqTQVzW gquaV4dYv2XXE1nUpzQs+DUQsQ== X-Google-Smtp-Source: APXvYqxtmP0JeLppB7oOEtW1q/AVNVbVYKTRYzHrmGsmpeZn/P8Sj8sCC5Bjv7PF3chiASN2azAz/w== X-Received: by 2002:adf:b741:: with SMTP id n1mr7046736wre.287.1553275856356; Fri, 22 Mar 2019 10:30:56 -0700 (PDT) Received: from debian-brgl.home ([2a01:cb1d:af:5b00:6d6c:8493:1ab5:dad7]) by smtp.gmail.com with ESMTPSA id z14sm11941881wrv.78.2019.03.22.10.30.55 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 22 Mar 2019 10:30:55 -0700 (PDT) From: Bartosz Golaszewski To: Linus Walleij Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, Bartosz Golaszewski Subject: [PATCH] gpio: mockup: fix debugfs read Date: Fri, 22 Mar 2019 18:30:52 +0100 Message-Id: <20190322173052.23763-1-brgl@bgdev.pl> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Sender: linux-gpio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org From: Bartosz Golaszewski The debugfs read callback must advance ppos or users using read() on the file descriptor will never get the EOL. This wasn't spotted before as I was using busybox cat for testing which uses sendfile() internally and only noticed it now when switched to cat from coreutils. Fixes: 2a9e27408e12 ("gpio: mockup: rework debugfs interface") Signed-off-by: Bartosz Golaszewski --- drivers/gpio/gpio-mockup.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c index 154d959e8993..74ba8b1d71d8 100644 --- a/drivers/gpio/gpio-mockup.c +++ b/drivers/gpio/gpio-mockup.c @@ -204,8 +204,9 @@ static ssize_t gpio_mockup_debugfs_read(struct file *file, struct gpio_mockup_chip *chip; struct seq_file *sfile; struct gpio_chip *gc; + int val, rv, cnt; char buf[3]; - int val, rv; + if (*ppos != 0) return 0; @@ -216,13 +217,14 @@ static ssize_t gpio_mockup_debugfs_read(struct file *file, gc = &chip->gc; val = gpio_mockup_get(gc, priv->offset); - snprintf(buf, sizeof(buf), "%d\n", val); + cnt = snprintf(buf, sizeof(buf), "%d\n", val); - rv = copy_to_user(usr_buf, buf, sizeof(buf)); + rv = copy_to_user(usr_buf, buf, cnt); if (rv) return rv; - return sizeof(buf) - 1; + *ppos += cnt; + return cnt; } static ssize_t gpio_mockup_debugfs_write(struct file *file,