Re: [Alsa-devel] [PATCH] Driver core: Don't ignore error returnsfrom probing

From: Jaroslav Kysela
Date: Fri Oct 06 2006 - 05:41:31 EST


On Fri, 6 Oct 2006, Cornelia Huck wrote:

> On Thu, 5 Oct 2006 17:03:24 -0400 (EDT),
> Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
>
> > Index: 18g20/drivers/base/bus.c
> > ===================================================================
> > --- 18g20.orig/drivers/base/bus.c
> > +++ 18g20/drivers/base/bus.c
> > @@ -453,8 +453,10 @@ void bus_remove_device(struct device * d
> > remove_deprecated_bus_links(dev);
> > sysfs_remove_link(&dev->bus->devices.kobj, dev->bus_id);
> > device_remove_attrs(dev->bus, dev);
> > - dev->is_registered = 0;
> > - klist_del(&dev->knode_bus);
> > + if (dev->is_registered) {
> > + dev->is_registered = 0;
> > + klist_del(&dev->knode_bus);
> > + }
> > pr_debug("bus %s: remove device %s\n", dev->bus->name, dev->bus_id);
> > device_release_driver(dev);
> > put_bus(dev->bus);
> > Index: 18g20/drivers/base/core.c
> > ===================================================================
> > --- 18g20.orig/drivers/base/core.c
> > +++ 18g20/drivers/base/core.c
> > @@ -485,7 +485,8 @@ int device_add(struct device *dev)
> > if ((error = bus_add_device(dev)))
> > goto BusError;
> > kobject_uevent(&dev->kobj, KOBJ_ADD);
> > - bus_attach_device(dev);
> > + if ((error = bus_attach_device(dev)))
> > + goto AttachError;
> > if (parent)
> > klist_add_tail(&dev->knode_parent, &parent->klist_children);
> >
> > @@ -504,6 +505,8 @@ int device_add(struct device *dev)
> > kfree(class_name);
> > put_device(dev);
> > return error;
> > + AttachError:
> > + bus_remove_device(dev);
> > BusError:
> > device_pm_remove(dev);
> > PMError:
>
> Hm, I don't think we should call device_release_driver if
> bus_attach_device failed (and I think calling bus_remove_device if
> bus_attach_device failed is unintuitive). I did a patch that added a
> function which undid just the things bus_add_device did (here:
> http://marc.theaimsgroup.com/?l=linux-kernel&m=115816560424389&w=2),
> which unfortunately got lost somewhere... (I'll rebase and resend.)

Yes, but it might be better to check dev->is_registered flag in
bus_remove_device() before device_release_driver() call to save some code,
rather than reuse most of code in bus_delete_device().

Jaroslav

-----
Jaroslav Kysela <perex@xxxxxxx>
Linux Kernel Sound Maintainer
ALSA Project, SUSE Labs
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