Re: [PATCH v5 08/11] devm-helpers: Add resource managed version of debugfs directory create function

[Christophe JAILLET]

Le 23/03/2024 à 22:25, Marek Behún a écrit :
> On Sat, 23 Mar 2024 22:10:40 +0100
> Christophe JAILLET <christophe.jaillet@xxxxxxxxxx> wrote:

..

> > >    static int pvt_ts_dbgfs_create(struct pvt_device *pvt, struct device *dev)
> > >    {
> > > -	pvt->dbgfs_dir = debugfs_create_dir(dev_name(dev), NULL);
> > > +	pvt->dbgfs_dir = devm_debugfs_create_dir(dev, dev_name(dev), NULL);
> > > +	if (IS_ERR(pvt->dbgfs_dir))
> > > +		return PTR_ERR(pvt->dbgfs_dir);
> >
> > Not sure if the test and error handling should be added here.
> > *If I'm correct*, functions related to debugfs already handle this case
> > and just do nothing. And failure in debugfs related code is not
> > considered as something that need to be reported and abort a probe function.
> >
> > Maybe the same other (already existing) tests in this patch should be
> > removed as well, in a separated patch.
>
> Functions related to debugfs maybe do, but devm_ resource management
> functions may fail to allocate release structure, and those errors need
> to be handled, AFAIK.

I would say no.
If this memory allocation fails, then debugfs_create_dir() will not be 
called, but that's not a really big deal if the driver itself can still 
run normally without it.

Up to you to leave it as-is or remove what I think is a useless error 
handling.
At least, maybe it could be said in the commit log, so that maintainers 
can comment on it, if they don't spot the error handling you introduce.

CJ

> Marek