Driver core: create lock/unlock functions for struct device

In the future, we are going to be changing the lock type for struct
device (once we get the lockdep infrastructure properly worked out)  To
make that changeover easier, and to possibly burry the lock in a
different part of struct device, let's create some functions to lock and
unlock a device so that no out-of-core code needs to be changed in the
future.

This patch creates the device_lock/unlock/trylock() functions, and
converts all in-tree users to them.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Dave Young <hidave.darkstar@gmail.com>
Cc: Ming Lei <tom.leiming@gmail.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Phil Carmody <ext-phil.2.carmody@nokia.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Len Brown <len.brown@intel.com>
Cc: Magnus Damm <damm@igel.co.jp>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Alex Chiang <achiang@hp.com>
Cc: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrew Patterson <andrew.patterson@hp.com>
Cc: Yu Zhao <yu.zhao@intel.com>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: Wolfram Sang <w.sang@pengutronix.de>
Cc: CHENG Renquan <rqcheng@smu.edu.sg>
Cc: Oliver Neukum <oliver@neukum.org>
Cc: Frans Pop <elendil@planet.nl>
Cc: David Vrabel <david.vrabel@csr.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 16 insertions, 1 deletions

diff --git a/include/linux/device.h b/include/linux/device.h
index f95d5bfe8248..182192892d45 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -106,7 +106,7 @@ extern int bus_unregister_notifier(struct bus_type *bus,
 
 /* All 4 notifers below get called with the target struct device *
  * as an argument. Note that those functions are likely to be called
- * with the device semaphore held in the core, so be careful.
+ * with the device lock held in the core, so be careful.
  */
 #define BUS_NOTIFY_ADD_DEVICE		0x00000001 /* device added */
 #define BUS_NOTIFY_DEL_DEVICE		0x00000002 /* device removed */
@@ -508,6 +508,21 @@ static inline bool device_async_suspend_enabled(struct device *dev)
 	return !!dev->power.async_suspend;
 }
 
+static inline void device_lock(struct device *dev)
+{
+	down(&dev->sem);
+}
+
+static inline int device_trylock(struct device *dev)
+{
+	return down_trylock(&dev->sem);
+}
+
+static inline void device_unlock(struct device *dev)
+{
+	up(&dev->sem);
+}
+
 void driver_init(void);
 
 /*