[Patch 3/7] driver core fixes: device_register() retval check in platform.c

[Patch 3/7] driver core fixes: device_register() retval check in platform.c

[Cornelia Huck]

From: Cornelia Huck <cornelia.huck@de.ibm.com>

Check the return value of device_register() in platform_bus_init().

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

---

 drivers/base/platform.c |   11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

--- linux-2.6.orig/drivers/base/platform.c
+++ linux-2.6/drivers/base/platform.c
@@ -563,8 +563,15 @@ EXPORT_SYMBOL_GPL(platform_bus_type);
 
 int __init platform_bus_init(void)
 {
-	device_register(&platform_bus);
-	return bus_register(&platform_bus_type);
+	int error;
+
+	error = device_register(&platform_bus);
+	if (error)
+		return error;
+	error =  bus_register(&platform_bus_type);
+	if (error)
+		device_unregister(&platform_bus);
+	return error;
 }
 
 #ifndef ARCH_HAS_DMA_GET_REQUIRED_MASK

[Patch 3/7] driver core fixes: device_register() retval check in platform.c

[Cornelia Huck]

From: Cornelia Huck <cornelia.huck@de.ibm.com>

Check the return value of device_register() in platform_bus_init().

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

---

 drivers/base/platform.c |   11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)

--- linux-2.6-CH.orig/drivers/base/platform.c
+++ linux-2.6-CH/drivers/base/platform.c
@@ -611,8 +611,15 @@ EXPORT_SYMBOL_GPL(platform_bus_type);
 
 int __init platform_bus_init(void)
 {
-	device_register(&platform_bus);
-	return bus_register(&platform_bus_type);
+	int error;
+
+	error = device_register(&platform_bus);
+	if (error)
+		return error;
+	error =  bus_register(&platform_bus_type);
+	if (error)
+		device_unregister(&platform_bus);
+	return error;
 }
 
 #ifndef ARCH_HAS_DMA_GET_REQUIRED_MASK

Re: [Patch 3/7] driver core fixes: device_register() retval check in platform.c

[Russell King]

On Mon, Nov 27, 2006 at 10:35:08AM +0100, Cornelia Huck wrote:
> From: Cornelia Huck <cornelia.huck@de.ibm.com>
> 
> Check the return value of device_register() in platform_bus_init().

I still say this is absolutely crazy.  If a bus does not get registered,
what happens to all the devices and drivers which are registered against
that bus?

I suspect that if this bus_register doesn't work, you'll see an oops
sooner or later.  So it might as well be a BUG_ON here.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:

Re: [Patch 3/7] driver core fixes: device_register() retval check in platform.c

[Cornelia Huck]

On Mon, 27 Nov 2006 11:24:47 +0000,
Russell King <rmk+lkml@arm.linux.org.uk> wrote:

> I still say this is absolutely crazy.  If a bus does not get registered,
> what happens to all the devices and drivers which are registered against
> that bus?

This is a generic problem. Does any driver check if the bus it is
registering against is really present? Or should the driver core check
whether a bus is registered when someone tries to register a
device/driver?

> I suspect that if this bus_register doesn't work, you'll see an oops
> sooner or later.  So it might as well be a BUG_ON here.

What we need to do here is to make sure we get to know that something
went really wrong here. If a BUG_ON is considered preferrable to oopses
on platform device registering, I can roll a patch.

-- 
Cornelia Huck
Linux for zSeries Developer
Tel.: +49-7031-16-4837, Mail: cornelia.huck@de.ibm.com