Messages in this thread Patch in this message |  | | | Date | Wed, 18 May 2005 10:42:23 +0200 | | From | Hannes Reinecke <> | | Subject | Re: [PATCH] fix error handling in bus_add_device |
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Greg KH wrote: > On Wed, May 18, 2005 at 09:19:37AM +0200, Hannes Reinecke wrote: >>Greg KH wrote: >>>On Thu, May 12, 2005 at 04:19:24PM +0200, Hannes Reinecke wrote: >>>>Hi Greg, >>>> >>>>this patch fixes the error handling in bus_add_device() and >>>>device_attach(). Previously it was 'interesting'. >>>>And totally confusing to boot. >>>I agree, that's why it has been rewritten in the -mm tree :) >>> >>>Anyway, your patch doesn't take into account that device_attach()'s >>>return value is tested in the bus_rescan_devices_helper(), so if you >>>change the return value, that also needs to be changed. >>> >>>But even in the -mm tree, the bus_add_devices() function has not had the >>>error handling added to it that you provided, is there any devices that >>>you are seeing that need this? >>> >>Not yet :-) >> >>I'm just doing some cleanups here which me and Kay Sievers will be >>exploiting in the near future. >>My main point is: >>either we do an error check in bus_add_device and return a proper >>status, or we don't and fix bus_add_device to be of type 'void'. >>And as some functions called by bus_add_device may fail I thought it >>reasonable to evaluate the return status properly. >>Unless you tell me that bus_add_device is a fire-and-forget procedure >>and we don't care at all for any failures. But then we should at least >>set the type of bus_add_device() to 'void'. >>You're the maintainer, you have to decide :-). >>I don't care either way, I just want to have it consistent. >> >>But you're correct about the bus_rescan_devices_helper. Fixed and new >>patch attached. > > Ok, I agree that we should have error checks in there. Now, could you > make your patch against the latest -mm tree instead due to all of the > changes involved in that area in my trees? That way I can apply it :) > Whee, innovations. Which your patches to -mm the whole thing is even easier and now actually looks quite sane. New patch attached.
Cheers,
Hannes -- Dr. Hannes Reinecke hare@suse.de SuSE Linux AG S390 & zSeries Maxfeldstraße 5 +49 911 74053 688 90409 Nürnberg http://www.suse.de From: Hannes Reinecke <hare@suse.de> Subject: Fix error handling in bus_add_device()
The error handling in bus_add_device() and device_attach() is simply non-existing. This patch propagates any error from device_attach to the upper layers to allow for a proper recovery.
--- linux-2.6.12-rc4-mm2/drivers/base/bus.c.orig 2005-05-18 10:26:50.000000000 +0200 +++ linux-2.6.12-rc4-mm2/drivers/base/bus.c 2005-05-18 10:36:08.000000000 +0200 @@ -270,11 +270,14 @@ int bus_add_device(struct device * dev) if (bus) { pr_debug("bus %s: add device %s\n", bus->name, dev->bus_id); - device_attach(dev); + error = device_attach(dev); klist_add_tail(&bus->klist_devices, &dev->knode_bus); - device_add_attrs(bus, dev); - sysfs_create_link(&bus->devices.kobj, &dev->kobj, dev->bus_id); - sysfs_create_link(&dev->kobj, &dev->bus->subsys.kset.kobj, "bus"); + if (error >= 0) + error = device_add_attrs(bus, dev); + if (!error) { + sysfs_create_link(&bus->devices.kobj, &dev->kobj, dev->bus_id); + sysfs_create_link(&dev->kobj, &dev->bus->subsys.kset.kobj, "bus"); + } } return error; } @@ -394,7 +397,7 @@ static int bus_rescan_devices_helper(str { int *count = data; - if (!dev->driver && device_attach(dev)) + if (!dev->driver && (device_attach(dev) > 0)) (*count)++; return 0; --- linux-2.6.12-rc4-mm2/drivers/base/dd.c.orig 2005-05-18 10:29:27.000000000 +0200 +++ linux-2.6.12-rc4-mm2/drivers/base/dd.c 2005-05-18 10:39:45.000000000 +0200 @@ -119,7 +119,8 @@ static int __device_attach(struct device * driver_probe_device() for each pair. If a compatible * pair is found, break out and return. * - * Returns 1 if the device was bound to a driver; 0 otherwise. + * Returns 1 if the device was bound to a driver; + * 0 if no matching device was found; error code otherwise. */ int device_attach(struct device * dev) { |  |