From patchwork Mon May 4 15:10:43 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johan Hovold X-Patchwork-Id: 467659 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 9ED691402AB for ; Tue, 5 May 2015 01:17:32 +1000 (AEST) Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b=N4zKObd/; dkim-atps=neutral Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752424AbbEDPRS (ORCPT ); Mon, 4 May 2015 11:17:18 -0400 Received: from mail-lb0-f181.google.com ([209.85.217.181]:34344 "EHLO mail-lb0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752065AbbEDPNq (ORCPT ); Mon, 4 May 2015 11:13:46 -0400 Received: by lbcga7 with SMTP id ga7so107205272lbc.1; Mon, 04 May 2015 08:13:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=o1824x9pAc+Mt9Bh76xWDBmXdmj7qgtpKqpdhdrIk8c=; b=N4zKObd/o/kBjFH4I41wG9FhLqtZU5DggzAKYs7tJmjcyaBlDr4eabvrn/HCqLQUat WhyKU6A0gCb6zwB99hCb36mEqx/fjIO8IADq0YgcNNIaWbCOHBqzRatJUhdnNR59lEqO Sfq9oMWqeACKJSYIqTeMPh94I9kXEcjrg/MnvweGXJUFmJyKpDltigI79elp1HKOU+44 HZ3cfsOacGD/Ebd/duKiO7xYhK96Y2NKXONeJT6OvFDPTHyE+6t/2cMAmD/QoK4I7x2P xdD2WsLzUaW8Rfk2x1QLJ8AXuJgqHPjd5koyVGIHgp0HyWKqbcK+LYbNfqGBihpeXfdD MofA== X-Received: by 10.112.120.199 with SMTP id le7mr19759263lbb.48.1430752425458; Mon, 04 May 2015 08:13:45 -0700 (PDT) Received: from xi.terra (c193-14-96-226.cust.tele2.se. [193.14.96.226]) by mx.google.com with ESMTPSA id r4sm3419785lae.13.2015.05.04.08.13.41 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 04 May 2015 08:13:44 -0700 (PDT) Received: from johan by xi.terra with local (Exim 4.84) (envelope-from ) id 1YpI3z-000437-F5; Mon, 04 May 2015 17:13:43 +0200 From: Johan Hovold To: Linus Walleij Cc: Alexandre Courbot , linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, Johan Hovold Subject: [PATCH v2 18/23] gpio: sysfs: clean up gpiod_export_link locking Date: Mon, 4 May 2015 17:10:43 +0200 Message-Id: <1430752248-15401-19-git-send-email-johan@kernel.org> X-Mailer: git-send-email 2.0.5 In-Reply-To: <1430752248-15401-1-git-send-email-johan@kernel.org> References: <1430752248-15401-1-git-send-email-johan@kernel.org> Sender: linux-gpio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org Drop unnecessary locking from gpiod_export_link. If the class device has not already been unregistered, class_find_device returns the ref-counted class device so there's no need for locking. Signed-off-by: Johan Hovold --- drivers/gpio/gpiolib-sysfs.c | 28 ++++++++-------------------- 1 file changed, 8 insertions(+), 20 deletions(-) diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c index 1161a46618dd..682e4d34999c 100644 --- a/drivers/gpio/gpiolib-sysfs.c +++ b/drivers/gpio/gpiolib-sysfs.c @@ -631,34 +631,22 @@ static int match_export(struct device *dev, const void *desc) int gpiod_export_link(struct device *dev, const char *name, struct gpio_desc *desc) { - int status = -EINVAL; + struct device *cdev; + int ret; if (!desc) { pr_warn("%s: invalid GPIO\n", __func__); return -EINVAL; } - mutex_lock(&sysfs_lock); - - if (test_bit(FLAG_EXPORT, &desc->flags)) { - struct device *tdev; - - tdev = class_find_device(&gpio_class, NULL, desc, match_export); - if (tdev != NULL) { - status = sysfs_create_link(&dev->kobj, &tdev->kobj, - name); - put_device(tdev); - } else { - status = -ENODEV; - } - } - - mutex_unlock(&sysfs_lock); + cdev = class_find_device(&gpio_class, NULL, desc, match_export); + if (!cdev) + return -ENODEV; - if (status) - gpiod_dbg(desc, "%s: status %d\n", __func__, status); + ret = sysfs_create_link(&dev->kobj, &cdev->kobj, name); + put_device(cdev); - return status; + return ret; } EXPORT_SYMBOL_GPL(gpiod_export_link);