From patchwork Mon Aug 8 22:31:42 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rafael Wysocki X-Patchwork-Id: 1047112 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter2.kernel.org (8.14.4/8.14.4) with ESMTP id p78MXDE4003402 for ; Mon, 8 Aug 2011 22:33:13 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753483Ab1HHWcx (ORCPT ); Mon, 8 Aug 2011 18:32:53 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:55707 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753108Ab1HHWcX (ORCPT ); Mon, 8 Aug 2011 18:32:23 -0400 Received: from localhost (localhost.localdomain [127.0.0.1]) by ogre.sisk.pl (Postfix) with ESMTP id 701271B7523; Mon, 8 Aug 2011 23:56:23 +0200 (CEST) Received: from ogre.sisk.pl ([127.0.0.1]) by localhost (ogre.sisk.pl [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 05995-06; Mon, 8 Aug 2011 23:55:51 +0200 (CEST) Received: from ferrari.rjw.lan (unknown [82.210.184.220]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ogre.sisk.pl (Postfix) with ESMTP id 7C9771B7897; Mon, 8 Aug 2011 23:55:51 +0200 (CEST) From: "Rafael J. Wysocki" To: Linux PM mailing list Subject: [PATCH 2/4] PM: Reference counting of power.subsys_data Date: Tue, 9 Aug 2011 00:31:42 +0200 User-Agent: KMail/1.13.6 (Linux/3.1.0-rc1+; KDE/4.6.0; x86_64; ; ) Cc: LKML , linux-sh@vger.kernel.org, Magnus Damm , Greg KH References: <201108090028.12698.rjw@sisk.pl> In-Reply-To: <201108090028.12698.rjw@sisk.pl> MIME-Version: 1.0 Message-Id: <201108090031.42691.rjw@sisk.pl> X-Virus-Scanned: amavisd-new at ogre.sisk.pl using MkS_Vir for Linux Sender: linux-sh-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter2.kernel.org [140.211.167.43]); Mon, 08 Aug 2011 22:33:14 +0000 (UTC) From: Rafael J. Wysocki Since the power.subsys_data device field will be used by multiple filesystems, introduce a reference counting mechanism for it to avoid freeing it prematurely or changing its value at a wrong time. Make the PM clocks management code that currently is the only user of power.subsys_data use the new reference counting. Signed-off-by: Rafael J. Wysocki --- drivers/base/power/Makefile | 2 drivers/base/power/clock_ops.c | 24 ++--------- drivers/base/power/common.c | 86 +++++++++++++++++++++++++++++++++++++++++ include/linux/pm.h | 3 + 4 files changed, 95 insertions(+), 20 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-sh" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Index: linux-2.6/drivers/base/power/common.c =================================================================== --- /dev/null +++ linux-2.6/drivers/base/power/common.c @@ -0,0 +1,86 @@ +/* + * drivers/base/power/common.c - Common device power management code. + * + * Copyright (C) 2011 Rafael J. Wysocki , Renesas Electronics Corp. + * + * This file is released under the GPLv2. + */ + +#include +#include +#include +#include +#include + +/** + * dev_pm_get_subsys_data - Create or refcount power.subsys_data for device. + * @dev: Device to handle. + * + * If power.subsys_data is NULL, point it to a new object, otherwise increment + * its reference counter. Return 1 if a new object has been created, otherwise + * return 0 or error code. + */ +int dev_pm_get_subsys_data(struct device *dev) +{ + struct pm_subsys_data *psd; + int ret = 0; + + psd = kzalloc(sizeof(*psd), GFP_KERNEL); + if (!psd) + return -ENOMEM; + + spin_lock_irq(&dev->power.lock); + + if (dev->power.subsys_data) { + dev->power.subsys_data->refcount++; + } else { + mutex_init(&psd->lock); + psd->refcount = 1; + dev->power.subsys_data = psd; + pm_clk_init(dev); + psd = NULL; + ret = 1; + } + + spin_unlock_irq(&dev->power.lock); + + /* kfree() verifies that its argument is nonzero. */ + kfree(psd); + + return ret; +} +EXPORT_SYMBOL_GPL(dev_pm_get_subsys_data); + +/** + * dev_pm_put_subsys_data - Drop reference to power.subsys_data. + * @dev: Device to handle. + * + * If the reference counter of power.subsys_data is zero after dropping the + * reference, power.subsys_data is removed. Return 1 if that happens or 0 + * otherwise. + */ +int dev_pm_put_subsys_data(struct device *dev) +{ + struct pm_subsys_data *psd; + int ret = 0; + + spin_lock_irq(&dev->power.lock); + + psd = dev_to_psd(dev); + if (!psd) { + ret = -EINVAL; + goto out; + } + + if (--psd->refcount == 0) { + dev->power.subsys_data = NULL; + kfree(psd); + ret = 1; + } + + out: + spin_unlock_irq(&dev->power.lock); + + return ret; +} +EXPORT_SYMBOL_GPL(dev_pm_put_subsys_data); Index: linux-2.6/include/linux/pm.h =================================================================== --- linux-2.6.orig/include/linux/pm.h +++ linux-2.6/include/linux/pm.h @@ -424,6 +424,7 @@ struct wakeup_source; struct pm_subsys_data { struct mutex lock; + unsigned int refcount; #ifdef CONFIG_PM_CLK struct list_head clock_list; #endif @@ -474,6 +475,8 @@ struct dev_pm_info { }; extern void update_pm_runtime_accounting(struct device *dev); +extern int dev_pm_get_subsys_data(struct device *dev); +extern int dev_pm_put_subsys_data(struct device *dev); /* * Power domains provide callbacks that are executed during system suspend, Index: linux-2.6/drivers/base/power/Makefile =================================================================== --- linux-2.6.orig/drivers/base/power/Makefile +++ linux-2.6/drivers/base/power/Makefile @@ -1,4 +1,4 @@ -obj-$(CONFIG_PM) += sysfs.o generic_ops.o +obj-$(CONFIG_PM) += sysfs.o generic_ops.o common.o obj-$(CONFIG_PM_SLEEP) += main.o wakeup.o obj-$(CONFIG_PM_RUNTIME) += runtime.o obj-$(CONFIG_PM_TRACE_RTC) += trace.o Index: linux-2.6/drivers/base/power/clock_ops.c =================================================================== --- linux-2.6.orig/drivers/base/power/clock_ops.c +++ linux-2.6/drivers/base/power/clock_ops.c @@ -140,12 +140,8 @@ void pm_clk_remove(struct device *dev, c void pm_clk_init(struct device *dev) { struct pm_subsys_data *psd = dev_to_psd(dev); - - if (!psd) - return; - - INIT_LIST_HEAD(&psd->clock_list); - mutex_init(&psd->lock); + if (psd) + INIT_LIST_HEAD(&psd->clock_list); } /** @@ -157,16 +153,8 @@ void pm_clk_init(struct device *dev) */ int pm_clk_create(struct device *dev) { - struct pm_subsys_data *psd; - - psd = kzalloc(sizeof(*psd), GFP_KERNEL); - if (!psd) { - dev_err(dev, "Not enough memory for PM clock data.\n"); - return -ENOMEM; - } - dev->power.subsys_data = psd; - pm_clk_init(dev); - return 0; + int ret = dev_pm_get_subsys_data(dev); + return ret < 0 ? ret : 0; } /** @@ -185,8 +173,6 @@ void pm_clk_destroy(struct device *dev) if (!psd) return; - dev->power.subsys_data = NULL; - mutex_lock(&psd->lock); list_for_each_entry_safe_reverse(ce, c, &psd->clock_list, node) @@ -194,7 +180,7 @@ void pm_clk_destroy(struct device *dev) mutex_unlock(&psd->lock); - kfree(psd); + dev_pm_put_subsys_data(dev); } #endif /* CONFIG_PM */