Re: [PATCH][2.6][CFT] rmmod floppy kills box fixes + default_device_remove

[Zwane Mwaikambo]

On Tue, 9 Sep 2003, Greg KH wrote:

> Ugh.  Sure, point out the theoretical :)
> 
> Any thoughts on how to solve this?

How about something like the following, the kobj_type.done is passed from 
the driver so the driver's presence can maintain it's persistence and 
we're guaranteed that the ->release() function is not running on a 
processor at completion time.

Index: linux-2.6.0-test5/drivers/base/core.c
===================================================================
RCS file: /build/cvsroot/linux-2.6.0-test5/drivers/base/core.c,v
retrieving revision 1.1.1.1
diff -u -p -B -r1.1.1.1 core.c
--- linux-2.6.0-test5/drivers/base/core.c	8 Sep 2003 22:07:57 -0000	1.1.1.1
+++ linux-2.6.0-test5/drivers/base/core.c	9 Sep 2003 18:38:45 -0000
@@ -334,6 +334,14 @@ void device_del(struct device * dev)
 
 }
 
+void device_release_notify(struct device *dev, struct completion *done)
+{
+	struct kobj_type *ktype = get_ktype(&dev->kobj);
+
+	init_completion(done);
+	ktype->done = done;
+}
+
 /**
  *	device_unregister - unregister device from system.
  *	@dev:	device going away.
Index: linux-2.6.0-test5/lib/kobject.c
===================================================================
RCS file: /build/cvsroot/linux-2.6.0-test5/lib/kobject.c,v
retrieving revision 1.1.1.1
diff -u -p -B -r1.1.1.1 kobject.c
--- linux-2.6.0-test5/lib/kobject.c	8 Sep 2003 22:08:55 -0000	1.1.1.1
+++ linux-2.6.0-test5/lib/kobject.c	9 Sep 2003 18:10:50 -0000
@@ -448,8 +448,12 @@ void kobject_cleanup(struct kobject * ko
 	if (kobj->k_name != kobj->name)
 		kfree(kobj->k_name);
 	kobj->k_name = NULL;
-	if (t && t->release)
+	if (t && t->release) {
 		t->release(kobj);
+		if (t->done)
+			complete(t->done);
+	}
+
 	if (s)
 		kset_put(s);
 }
Index: linux-2.6.0-test5/include/linux/kobject.h
===================================================================
RCS file: /build/cvsroot/linux-2.6.0-test5/include/linux/kobject.h,v
retrieving revision 1.1.1.1
diff -u -p -B -r1.1.1.1 kobject.h
--- linux-2.6.0-test5/include/linux/kobject.h	8 Sep 2003 22:08:50 -0000	1.1.1.1
+++ linux-2.6.0-test5/include/linux/kobject.h	9 Sep 2003 17:47:19 -0000
@@ -59,6 +59,7 @@ extern void kobject_put(struct kobject *
 
 struct kobj_type {
 	void (*release)(struct kobject *);
+	struct completion	* done;
 	struct sysfs_ops	* sysfs_ops;
 	struct attribute	** default_attrs;
 };


Then in the driver module_exit;

void cleanup_module(void)
{
	...
	struct completion done;
	struct device *dev = ...

	device_release_notify(dev, &done);

	...

	wait_for_completion(&done);
}
-
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