Revision ed48ece27cd3d5ee0354c32bbaec0f3e1d4715c3 authored by Tejun Heo on 18 September 2012, 19:48:43 UTC, committed by Tejun Heo on 19 September 2012, 17:13:12 UTC
The existing work_on_cpu() implementation is hugely inefficient. It creates a new kthread, execute that single function and then let the kthread die on each invocation. Now that system_wq can handle concurrent executions, there's no advantage of doing this. Reimplement work_on_cpu() using system_wq which makes it simpler and way more efficient. stable: While this isn't a fix in itself, it's needed to fix a workqueue related bug in cpufreq/powernow-k8. AFAICS, this shouldn't break other existing users. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Jiri Kosina <jkosina@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Len Brown <lenb@kernel.org> Cc: Rafael J. Wysocki <rjw@sisk.pl> Cc: stable@vger.kernel.org
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media-device.h
/*
* Media device
*
* Copyright (C) 2010 Nokia Corporation
*
* Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
* Sakari Ailus <sakari.ailus@iki.fi>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef _MEDIA_DEVICE_H
#define _MEDIA_DEVICE_H
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
#include <media/media-devnode.h>
#include <media/media-entity.h>
struct device;
/**
* struct media_device - Media device
* @dev: Parent device
* @devnode: Media device node
* @model: Device model name
* @serial: Device serial number (optional)
* @bus_info: Unique and stable device location identifier
* @hw_revision: Hardware device revision
* @driver_version: Device driver version
* @entity_id: ID of the next entity to be registered
* @entities: List of registered entities
* @lock: Entities list lock
* @graph_mutex: Entities graph operation lock
*
* This structure represents an abstract high-level media device. It allows easy
* access to entities and provides basic media device-level support. The
* structure can be allocated directly or embedded in a larger structure.
*
* The parent @dev is a physical device. It must be set before registering the
* media device.
*
* @model is a descriptive model name exported through sysfs. It doesn't have to
* be unique.
*/
struct media_device {
/* dev->driver_data points to this struct. */
struct device *dev;
struct media_devnode devnode;
char model[32];
char serial[40];
char bus_info[32];
u32 hw_revision;
u32 driver_version;
u32 entity_id;
struct list_head entities;
/* Protects the entities list */
spinlock_t lock;
/* Serializes graph operations. */
struct mutex graph_mutex;
int (*link_notify)(struct media_pad *source,
struct media_pad *sink, u32 flags);
};
/* media_devnode to media_device */
#define to_media_device(node) container_of(node, struct media_device, devnode)
int __must_check media_device_register(struct media_device *mdev);
void media_device_unregister(struct media_device *mdev);
int __must_check media_device_register_entity(struct media_device *mdev,
struct media_entity *entity);
void media_device_unregister_entity(struct media_entity *entity);
/* Iterate over all entities. */
#define media_device_for_each_entity(entity, mdev) \
list_for_each_entry(entity, &(mdev)->entities, list)
#endif
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