Re: [PATCH V5 net-next 1/8] debugfs: Add debugfs_create_devm_dir() helper

[Jijie Shao]

on 2024/12/6 19:40, Greg KH wrote:
> On Fri, Dec 06, 2024 at 07:16:22PM +0800, Jijie Shao wrote:
> > Add debugfs_create_devm_dir() helper
> >
> > Signed-off-by: Jijie Shao <shaojijie@xxxxxxxxxx>
> > ---
> >   fs/debugfs/inode.c      | 36 ++++++++++++++++++++++++++++++++++++
> >   include/linux/debugfs.h | 10 ++++++++++
> >   2 files changed, 46 insertions(+)
> >
> > diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
> > index 38a9c7eb97e6..f682c4952a27 100644
> > --- a/fs/debugfs/inode.c
> > +++ b/fs/debugfs/inode.c
> > @@ -610,6 +610,42 @@ struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
> >   }
> >   EXPORT_SYMBOL_GPL(debugfs_create_dir);
> >   
> > +static void debugfs_remove_devm(void *dentry_rwa)
> > +{
> > +	struct dentry *dentry = dentry_rwa;
> > +
> > +	debugfs_remove(dentry);
> > +}
> > +
> > +/**
> > + * debugfs_create_devm_dir - Managed debugfs_create_dir()
> > + * @dev: Device that owns the action
> > + * @name: a pointer to a string containing the name of the directory to
> > + *        create.
> > + * @parent: a pointer to the parent dentry for this file.  This should be a
> > + *          directory dentry if set.  If this parameter is NULL, then the
> > + *          directory will be created in the root of the debugfs filesystem.
> > + * Managed debugfs_create_dir(). dentry will automatically be remove on
> > + * driver detach.
> > + */
> > +struct dentry *debugfs_create_devm_dir(struct device *dev, const char *name,
> > +				       struct dentry *parent)
> > +{
> > +	struct dentry *dentry;
> > +	int ret;
> > +
> > +	dentry = debugfs_create_dir(name, parent);
> > +	if (IS_ERR(dentry))
> > +		return dentry;
> > +
> > +	ret = devm_add_action_or_reset(dev, debugfs_remove_devm, dentry);
> > +	if (ret)
> > +		ERR_PTR(ret);
> You don't clean up the directory you created if this failed?  Why not?

Don't need to clean up.
in devm_add_action_or_reset(), if failed, will call action: debugfs_remove_devm(),
So, not clean up again.

#define devm_add_action_or_reset(dev, action, data) \
	__devm_add_action_or_reset(dev, action, data, #action)

static inline int __devm_add_action_or_reset(struct device *dev, void (*action)(void *),
					     void *data, const char *name)
{
	int ret;

	ret = __devm_add_action(dev, action, data, name);
	if (ret)
		action(data);

	return ret;
}

But there's a problem with this, I missed return.
I will add return in v6.

Thanks,
Jijie Shao