Re: klists and struct device semaphores

[Patrick Mochel <mochel@digitalimplant.org>]

On Wed, 30 Mar 2005, Dmitry Torokhov wrote:

> Will the lock be exported (via helper functions)? I always felt dirty using
> subsys.rwsem because it I think it was supposed to be implementation detail.

Sure, why not? See the attached patch for helpers, exported GPL only of
course.

Thanks,


	Pat

===== drivers/base/core.c 1.97 vs edited =====
--- 1.97/drivers/base/core.c	2005-03-24 19:07:33 -08:00
+++ edited/drivers/base/core.c	2005-03-30 21:20:54 -08:00
@@ -196,6 +196,33 @@


 /**
+ *	device_lock - lock device by taking its semaphore
+ *	@dev:	Device to lock
+ */
+
+void device_lock(struct device * dev)
+{
+	if (dev)
+		down(&dev->sem);
+}
+
+EXPORT_SYMBOL_GPL(device_lock);
+
+
+/**
+ *	device_unlock - unlock device
+ *	@dev:	Device we're unlocking
+ */
+
+void device_unlock(struct device * dev)
+{
+	if (dev)
+		up(&dev->sem);
+}
+
+EXPORT_SYMBOL_GPL(device_unlock);
+
+/**
  *	device_initialize - init device structure.
  *	@dev:	device.
  *
===== include/linux/device.h 1.147 vs edited =====
--- 1.147/include/linux/device.h	2005-03-24 19:07:33 -08:00
+++ edited/include/linux/device.h	2005-03-30 21:17:28 -08:00
@@ -325,6 +325,9 @@
 extern int device_for_each_child(struct device *, void *,
 		     int (*fn)(struct device *, void *));

+extern void device_lock(struct device * dev);
+extern void device_unlock(struct device * dev);
+
 /*
  * Manual binding of a device to driver. See drivers/base/bus.c
  * for information on use.
-
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