Re: [Bluez-devel] Oops involving RFCOMM and sysfs

Dave Young
2008-01-21T03:16:01Z

On Jan 18, 2008 7:26 PM, Cornelia Huck <cornelia.huck@de.ibm.com> wrote:
> On Fri, 18 Jan 2008 18:34:55 +0800,
> "Dave Young" <hidave.darkstar@gmail.com> wrote:
>
>
> > On Jan 18, 2008 6:23 PM, Cornelia Huck <cornelia.huck@de.ibm.com> wrote:
> > > On Fri, 18 Jan 2008 10:19:33 +0100,
> > > Cornelia Huck <cornelia.huck@de.ibm.com> wrote:
> > >
> > > > >
> > > > > 1314 if (IS_ERR(new_parent_kobj)) {
> > > > > 1315 error = PTR_ERR(new_parent_kobj);
> > > > > 1316 put_device(new_parent);
> > > > > 1317 goto out;
> > > > > 1318 }
> > > > > 1319 pr_debug("DEVICE: moving '%s' to '%s'\n", dev->bus_id,
> > > > > 1320 new_parent ? new_parent->bus_id : "<NULL>");
> > > > > 1321 error = kobject_move(&dev->kobj, new_parent_kobj);
> > > > > 1322 if (error) {
> > > > > 1323 put_device(new_parent);
> > > > >
> > > > > imagine new_parent is NULL, then the new_parent_kobj should be put
> > > >
> > > > No, we would need a put_device_parent() (crappy name) which puts the
> > > > reference iff get_device_parent() grabbed it.
> > >
> > > And looking at Greg's patchset, it has cleanup_device_parent(), which
> > > does just that. But it is only called in device_del(), not when
> > > device_move() has errors.
> > >
> > > (get_device_parent() also always returns a pointer to a kobject or
> > > NULL, so we can get rid of those IS_ERR() checks in setup_parent() and
> > > device_move() as well.)
> > >
> >
> > Hmm, thanks.
> > I will be offline during weekend, but I will still check the
> > device_move and other code if I have time.
>
> Just hacked together the following against Greg's tree:
>
> COMPLETELY UNTESTED DO NOT APPLY
>
> ---
> drivers/base/core.c | 33 ++++++++++++++++-----------------
> 1 files changed, 16 insertions(+), 17 deletions(-)
>
> --- linux-2.6.orig/drivers/base/core.c
> +++ linux-2.6/drivers/base/core.c
> @@ -553,6 +553,8 @@ static struct kobject *get_device_parent
> }
>
> static inline void cleanup_device_parent(struct device *dev) {}
> +static inline void cleanup_glue_dir(struct device *dev,
> + struct kobject *kobj) {}
> #else
> static struct kobject *virtual_device_parent(struct device *dev)
> {
> @@ -617,27 +619,27 @@ static struct kobject *get_device_parent
> return NULL;
> }
>
> -static void cleanup_device_parent(struct device *dev)
> +static void cleanup_glue_dir(struct device *dev, struct kobject *kobj)
> {
> - struct kobject *glue_dir = dev->kobj.parent;
> -
> /* see if we live in a "glue" directory */
> - if (!dev->class || glue_dir->kset != &dev->class->class_dirs)
> + if (!dev->class || kobj->kset != &dev->class->class_dirs)
> return;
>
> - kobject_put(glue_dir);
> + kobject_put(kobj);
> +}
> +
> +static void cleanup_device_parent(struct device *dev)
> +{
> + cleanup_glue_dir(dev, dev->kobj.parent);
> }
> #endif
>
> -static int setup_parent(struct device *dev, struct device *parent)
> +static void setup_parent(struct device *dev, struct device *parent)
> {
> struct kobject *kobj;
> kobj = get_device_parent(dev, parent);
> - if (IS_ERR(kobj))
> - return PTR_ERR(kobj);
> if (kobj)
> dev->kobj.parent = kobj;
> - return 0;
> }
>
> static int device_add_class_symlinks(struct device *dev)
> @@ -782,9 +784,7 @@ int device_add(struct device *dev)
> pr_debug("device: '%s': %s\n", dev->bus_id, __FUNCTION__);
>
> parent = get_device(dev->parent);
> - error = setup_parent(dev, parent);
> - if (error)
> - goto Error;
> + setup_parent(dev, parent);
>
> /* first, register with generic layer. */
> error = kobject_add(&dev->kobj, dev->kobj.parent, "%s", dev->bus_id);
> @@ -862,6 +862,7 @@ int device_add(struct device *dev)
> kobject_uevent(&dev->kobj, KOBJ_REMOVE);
> kobject_del(&dev->kobj);
> Error:
> + cleanup_device_parent(dev);
> if (parent)
> put_device(parent);
> goto Done;
> @@ -1303,15 +1304,12 @@ int device_move(struct device *dev, stru
>
> new_parent = get_device(new_parent);
> new_parent_kobj = get_device_parent (dev, new_parent);
> - if (IS_ERR(new_parent_kobj)) {
> - error = PTR_ERR(new_parent_kobj);
> - put_device(new_parent);
> - goto out;
> - }
> +
> pr_debug("device: '%s': %s: moving to '%s'\n", dev->bus_id,
> __FUNCTION__, new_parent ? new_parent->bus_id : "<NULL>");
> error = kobject_move(&dev->kobj, new_parent_kobj);
> if (error) {
> + cleanup_glue_dir(dev, new_parent_kobj);
> put_device(new_parent);
> goto out;
> }
> @@ -1334,6 +1332,7 @@ int device_move(struct device *dev, stru
> klist_add_tail(&dev->knode_parent,
> &old_parent->klist_children);
> }
> + cleanup_glue_dir(dev, new_parent_kobj);
> put_device(new_parent);
> goto out;
> }
>

Looks good.