Re: [01/12] driver core fixes: make_class_name() retval check

[Cornelia Huck]

On Thu, 14 Sep 2006 14:01:33 +0200,
Martin Waitz <tali@xxxxxxxxxxxxxx> wrote:

> perhaps it makes sense to return NULL in make_class_name on error,
> to have consistent error return values?

It should make the code a bit nicer, I think. But I'm not sure if it's
worth the hassle (config_sysfs_deprecated.patch moves make_class_name()
under CONFIG_SYSFS_DEPRECATED).

Anyway, here is a patch against the latest version of Greg's tree:


From: Cornelia Huck <cornelia.huck@xxxxxxxxxx>

Make make_class_name() return NULL on error and fixup callers in the
driver core.

Signed-off-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx>

 class.c |   12 ++++++++----
 core.c  |    7 +++++--
 2 files changed, 13 insertions(+), 6 deletions(-)

diff -Naurp linux-2.6.18-rc7/drivers/base/class.c linux-2.6.18-rc7+CH/drivers/base/class.c
--- linux-2.6.18-rc7/drivers/base/class.c	2006-09-15 10:38:55.000000000 +0200
+++ linux-2.6.18-rc7+CH/drivers/base/class.c	2006-09-15 12:18:30.000000000 +0200
@@ -360,7 +360,7 @@ char *make_class_name(const char *name, 
 
 	class_name = kmalloc(size, GFP_KERNEL);
 	if (!class_name)
-		return ERR_PTR(-ENOMEM);
+		return NULL;
 
 	strcpy(class_name, name);
 	strcat(class_name, ":");
@@ -407,8 +407,11 @@ static int make_deprecated_class_device_
 		return 0;
 
 	class_name = make_class_name(class_dev->class->name, &class_dev->kobj);
-	error = sysfs_create_link(&class_dev->dev->kobj, &class_dev->kobj,
-				  class_name);
+	if (!class_name)
+		error = sysfs_create_link(&class_dev->dev->kobj,
+					  &class_dev->kobj, class_name);
+	else
+		error = -ENOMEM;
 	kfree(class_name);
 	return error;
 }
@@ -769,7 +772,8 @@ void class_device_del(struct class_devic
 #ifdef CONFIG_SYSFS_DEPRECATED
 		class_name = make_class_name(class_dev->class->name,
 					     &class_dev->kobj);
-		sysfs_remove_link(&class_dev->dev->kobj, class_name);
+		if (class_name)
+			sysfs_remove_link(&class_dev->dev->kobj, class_name);
 #endif
 		sysfs_remove_link(&class_dev->kobj, "device");
 	}
diff -Naurp linux-2.6.18-rc7/drivers/base/core.c linux-2.6.18-rc7+CH/drivers/base/core.c
--- linux-2.6.18-rc7/drivers/base/core.c	2006-09-15 10:39:03.000000000 +0200
+++ linux-2.6.18-rc7+CH/drivers/base/core.c	2006-09-15 11:01:58.000000000 +0200
@@ -443,7 +443,9 @@ int device_add(struct device *dev)
 		if ((parent) && (!device_is_virtual(dev))) {
 			sysfs_create_link(&dev->kobj, &dev->parent->kobj, "device");
 			class_name = make_class_name(dev->class->name, &dev->kobj);
-			sysfs_create_link(&dev->parent->kobj, &dev->kobj, class_name);
+			if (class_name)
+				sysfs_create_link(&dev->parent->kobj,
+						  &dev->kobj, class_name);
 		}
 #endif
 	}
@@ -574,7 +576,8 @@ void device_del(struct device * dev)
 			char *class_name = NULL;
 
 			class_name = make_class_name(dev->class->name, &dev->kobj);
-			sysfs_remove_link(&dev->parent->kobj, class_name);
+			if (class_name)
+				sysfs_remove_link(&dev->parent->kobj, class_name);
 			kfree(class_name);
 #endif
 			sysfs_remove_link(&dev->kobj, "device");
-
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