linux-kernel - Re: [PATCH 2/2] drm/debugfs: add descriptions to struct parameters

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Message-ID: <Y7866924YruF9OrY@phenom.ffwll.local>
Date:   Wed, 11 Jan 2023 23:40:43 +0100
From:   Daniel Vetter <daniel@...ll.ch>
To:     Maíra Canal <mcanal@...lia.com>
Cc:     Stephen Rothwell <sfr@...b.auug.org.au>,
        Jani Nikula <jani.nikula@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...il.com>,
        Melissa Wen <mwen@...lia.com>,
        André Almeida <andrealmeid@...lia.com>,
        linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH 2/2] drm/debugfs: add descriptions to struct parameters

On Mon, Jan 09, 2023 at 08:28:20AM -0300, Maíra Canal wrote:
> On 1/6/23 17:19, Daniel Vetter wrote:
> > On Thu, Jan 05, 2023 at 04:30:39PM -0300, Maíra Canal wrote:
> > > The structs drm_debugfs_info and drm_debugfs_entry don't have
> > > descriptions for their parameters, which is causing the following warnings:
> > > 
> > > include/drm/drm_debugfs.h:93: warning: Function parameter or member
> > > 'name' not described in 'drm_debugfs_info'
> > > include/drm/drm_debugfs.h:93: warning: Function parameter or member
> > > 'show' not described in 'drm_debugfs_info'
> > > include/drm/drm_debugfs.h:93: warning: Function parameter or member
> > > 'driver_features' not described in 'drm_debugfs_info'
> > > include/drm/drm_debugfs.h:93: warning: Function parameter or member
> > > 'data' not described in 'drm_debugfs_info'
> > > include/drm/drm_debugfs.h:105: warning: Function parameter or member
> > > 'dev' not described in 'drm_debugfs_entry'
> > > include/drm/drm_debugfs.h:105: warning: Function parameter or member
> > > 'file' not described in 'drm_debugfs_entry'
> > > include/drm/drm_debugfs.h:105: warning: Function parameter or member
> > > 'list' not described in 'drm_debugfs_entry'
> > > 
> > > Therefore, fix the warnings by adding descriptions to all struct
> > > parameters.
> > > 
> > > Reported-by: Stephen Rothwell <sfr@...b.auug.org.au>
> > > Signed-off-by: Maíra Canal <mcanal@...lia.com>
> > > ---
> > >   include/drm/drm_debugfs.h | 18 ++++++++++++++++++
> > >   1 file changed, 18 insertions(+)
> > > 
> > > diff --git a/include/drm/drm_debugfs.h b/include/drm/drm_debugfs.h
> > > index 53b7297260a5..7616f457ce70 100644
> > > --- a/include/drm/drm_debugfs.h
> > > +++ b/include/drm/drm_debugfs.h
> > > @@ -86,9 +86,22 @@ struct drm_info_node {
> > >    * core.
> > >    */
> > >   struct drm_debugfs_info {
> > > +	/** @name: File name */
> > >   	const char *name;
> > > +
> > > +	/**
> > > +	 * @show:
> > > +	 *
> > > +	 * Show callback. &seq_file->private will be set to the &struct
> > > +	 * drm_debugfs_entry corresponding to the instance of this info
> > > +	 * on a given &struct drm_device.
> > 
> > So this is a bit late, but why don't we pass that drm_debugfs_entry as an
> > explicit parameter? Or maybe just the struct drm_device, because that and
> > the void *data is really all there is to pass along. Would give us more
> > type-safety, which really is the main reason for having drm-specific
> > debugfs functions.
> 
> It seems like a better idea to pass the drm_debugfs_entry as an explicit
> parameter. I can work on it, but I guess it is a better idea to finish
> the conversion of all drm_debugfs_create_files() to drm_debugfs_add_files()
> and then perform the change in the show() signature.

So drm_debugfs_entry still feels like a bit too high level, do callers
really need that? They get the void * and I guess need the struct
drm_device *

This really starts to matter more when we also roll this out for
connector/crtc, then you can give them directly a pointer to that. And the
drm_debugfs_entry thing becomes an implementation detail entirely.

Or do I miss something?

Also yes we can do that later on, it shouldn't be too annyoing to roll
out.
-Daniel
> 
> Best Regards,
> - Maíra Canal
> 
> > 
> > Either way, on the series: Reviewed-by: Daniel Vetter <daniel.vetter@...ll.ch>
> > 
> > > +	 */
> > >   	int (*show)(struct seq_file*, void*);
> > > +
> > > +	/** @driver_features: Required driver features for this entry. */
> > >   	u32 driver_features;
> > > +
> > > +	/** @data: Driver-private data, should not be device-specific. */
> > >   	void *data;
> > >   };
> > > @@ -99,8 +112,13 @@ struct drm_debugfs_info {
> > >    * drm_debugfs_info on a &struct drm_device.
> > >    */
> > >   struct drm_debugfs_entry {
> > > +	/** @dev: &struct drm_device for this node. */
> > >   	struct drm_device *dev;
> > > +
> > > +	/** @file: Template for this node. */
> > >   	struct drm_debugfs_info file;
> > > +
> > > +	/** @list: Linked list of all device nodes. */
> > >   	struct list_head list;
> > >   };
> > > -- 
> > > 2.39.0
> > > 
> > 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch