[PATCH] nouveau: no need to check return value of debugfs_create functions

[PATCH] nouveau: no need to check return value of debugfs_create functions

[Greg Kroah-Hartman]

When calling debugfs functions, there is no need to ever check the
return value.  The function can work or not, but the code logic should
never do something different based on this.

Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Cc: nouveau@lists.freedesktop.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpu/drm/nouveau/nouveau_debugfs.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_debugfs.c b/drivers/gpu/drm/nouveau/nouveau_debugfs.c
index 080e964d49aa..d1c82fc45a68 100644
--- a/drivers/gpu/drm/nouveau/nouveau_debugfs.c
+++ b/drivers/gpu/drm/nouveau/nouveau_debugfs.c
@@ -224,14 +224,10 @@ nouveau_drm_debugfs_init(struct drm_minor *minor)
 	struct dentry *dentry;
 	int i;
 
-	for (i = 0; i < ARRAY_SIZE(nouveau_debugfs_files); i++) {
-		dentry = debugfs_create_file(nouveau_debugfs_files[i].name,
-					     S_IRUGO | S_IWUSR,
-					     minor->debugfs_root, minor->dev,
-					     nouveau_debugfs_files[i].fops);
-		if (!dentry)
-			return -ENOMEM;
-	}
+	for (i = 0; i < ARRAY_SIZE(nouveau_debugfs_files); i++)
+		debugfs_create_file(nouveau_debugfs_files[i].name,
+				    S_IRUGO | S_IWUSR, minor->debugfs_root,
+				    minor->dev, nouveau_debugfs_files[i].fops);
 
 	drm_debugfs_create_files(nouveau_debugfs_list,
 				 NOUVEAU_DEBUGFS_ENTRIES,
-- 
2.25.0

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Re: [Nouveau] [PATCH] nouveau: no need to check return value of debugfs_create functions

[Ben Skeggs]

On Sun, 9 Feb 2020 at 22:56, Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> When calling debugfs functions, there is no need to ever check the
> return value.  The function can work or not, but the code logic should
> never do something different based on this.
Thanks!

>
> Cc: Ben Skeggs <bskeggs@redhat.com>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: dri-devel@lists.freedesktop.org
> Cc: nouveau@lists.freedesktop.org
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
>  drivers/gpu/drm/nouveau/nouveau_debugfs.c | 12 ++++--------
>  1 file changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/nouveau/nouveau_debugfs.c b/drivers/gpu/drm/nouveau/nouveau_debugfs.c
> index 080e964d49aa..d1c82fc45a68 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_debugfs.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_debugfs.c
> @@ -224,14 +224,10 @@ nouveau_drm_debugfs_init(struct drm_minor *minor)
>         struct dentry *dentry;
>         int i;
>
> -       for (i = 0; i < ARRAY_SIZE(nouveau_debugfs_files); i++) {
> -               dentry = debugfs_create_file(nouveau_debugfs_files[i].name,
> -                                            S_IRUGO | S_IWUSR,
> -                                            minor->debugfs_root, minor->dev,
> -                                            nouveau_debugfs_files[i].fops);
> -               if (!dentry)
> -                       return -ENOMEM;
> -       }
> +       for (i = 0; i < ARRAY_SIZE(nouveau_debugfs_files); i++)
> +               debugfs_create_file(nouveau_debugfs_files[i].name,
> +                                   S_IRUGO | S_IWUSR, minor->debugfs_root,
> +                                   minor->dev, nouveau_debugfs_files[i].fops);
>
>         drm_debugfs_create_files(nouveau_debugfs_list,
>                                  NOUVEAU_DEBUGFS_ENTRIES,
> --
> 2.25.0
>
> _______________________________________________
> Nouveau mailing list
> Nouveau@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/nouveau
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Re: [Nouveau] [PATCH] nouveau: no need to check return value of debugfs_create functions

[John Hubbard]

On 2/9/20 2:55 AM, Greg Kroah-Hartman wrote:
> When calling debugfs functions, there is no need to ever check the
> return value.  The function can work or not, but the code logic should
> never do something different based on this.
> 

Should we follow that line of reasoning further, and simply return void
from the debugfs functions--rather than playing whack-a-mole with this
indefinitely?


thanks,
-- 
John Hubbard
NVIDIA

> Cc: Ben Skeggs <bskeggs@redhat.com>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: dri-devel@lists.freedesktop.org
> Cc: nouveau@lists.freedesktop.org
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
>  drivers/gpu/drm/nouveau/nouveau_debugfs.c | 12 ++++--------
>  1 file changed, 4 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/nouveau/nouveau_debugfs.c b/drivers/gpu/drm/nouveau/nouveau_debugfs.c
> index 080e964d49aa..d1c82fc45a68 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_debugfs.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_debugfs.c
> @@ -224,14 +224,10 @@ nouveau_drm_debugfs_init(struct drm_minor *minor)
>  	struct dentry *dentry;
>  	int i;
>  
> -	for (i = 0; i < ARRAY_SIZE(nouveau_debugfs_files); i++) {
> -		dentry = debugfs_create_file(nouveau_debugfs_files[i].name,
> -					     S_IRUGO | S_IWUSR,
> -					     minor->debugfs_root, minor->dev,
> -					     nouveau_debugfs_files[i].fops);
> -		if (!dentry)
> -			return -ENOMEM;
> -	}
> +	for (i = 0; i < ARRAY_SIZE(nouveau_debugfs_files); i++)
> +		debugfs_create_file(nouveau_debugfs_files[i].name,
> +				    S_IRUGO | S_IWUSR, minor->debugfs_root,
> +				    minor->dev, nouveau_debugfs_files[i].fops);
>  
>  	drm_debugfs_create_files(nouveau_debugfs_list,
>  				 NOUVEAU_DEBUGFS_ENTRIES,
> 
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Re: [Nouveau] [PATCH] nouveau: no need to check return value of debugfs_create functions

[Greg Kroah-Hartman]

On Thu, Feb 13, 2020 at 02:30:09PM -0800, John Hubbard wrote:
> On 2/9/20 2:55 AM, Greg Kroah-Hartman wrote:
> > When calling debugfs functions, there is no need to ever check the
> > return value.  The function can work or not, but the code logic should
> > never do something different based on this.
> > 
> 
> Should we follow that line of reasoning further, and simply return void
> from the debugfs functions--rather than playing whack-a-mole with this
> indefinitely?

That is what we (well I) have been doing.  Look at all of the changes
that have happened to include/linux/debugfs.h over the past few
releases.  I'm slowly winnowing down the api to make it impossible to
get wrong for this type of thing, and am almost there.

DRM is the big fish left to tackle, I have submitted some patches in the
past, but lots more cleanup needs to be done to get them into mergable
shape.  I just need to find the time...

thanks,

greg k-h
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Re: [Nouveau] [PATCH] nouveau: no need to check return value of debugfs_create functions

[John Hubbard]

On 2/13/20 2:39 PM, Greg Kroah-Hartman wrote:
> On Thu, Feb 13, 2020 at 02:30:09PM -0800, John Hubbard wrote:
>> On 2/9/20 2:55 AM, Greg Kroah-Hartman wrote:
>>> When calling debugfs functions, there is no need to ever check the
>>> return value.  The function can work or not, but the code logic should
>>> never do something different based on this.
>>>
>>
>> Should we follow that line of reasoning further, and simply return void
>> from the debugfs functions--rather than playing whack-a-mole with this
>> indefinitely?
> 
> That is what we (well I) have been doing.  Look at all of the changes
> that have happened to include/linux/debugfs.h over the past few
> releases.  I'm slowly winnowing down the api to make it impossible to
> get wrong for this type of thing, and am almost there.
>


Oops, I see now that you have already been very busy with this. :)  
Looking good...


thanks,
-- 
John Hubbard
NVIDIA
 
> DRM is the big fish left to tackle, I have submitted some patches in the
> past, but lots more cleanup needs to be done to get them into mergable
> shape.  I just need to find the time...
>>
> thanks,
> 
> greg k-h
> 
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Re: [Nouveau] [PATCH] nouveau: no need to check return value of debugfs_create functions

[Daniel Vetter]

On Thu, Feb 13, 2020 at 11:39 PM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Thu, Feb 13, 2020 at 02:30:09PM -0800, John Hubbard wrote:
> > On 2/9/20 2:55 AM, Greg Kroah-Hartman wrote:
> > > When calling debugfs functions, there is no need to ever check the
> > > return value.  The function can work or not, but the code logic should
> > > never do something different based on this.
> > >
> >
> > Should we follow that line of reasoning further, and simply return void
> > from the debugfs functions--rather than playing whack-a-mole with this
> > indefinitely?
>
> That is what we (well I) have been doing.  Look at all of the changes
> that have happened to include/linux/debugfs.h over the past few
> releases.  I'm slowly winnowing down the api to make it impossible to
> get wrong for this type of thing, and am almost there.
>
> DRM is the big fish left to tackle, I have submitted some patches in the
> past, but lots more cleanup needs to be done to get them into mergable
> shape.  I just need to find the time...

Just to avoid duplication, Wambui (cc'ed) just started working on
this. Expect a lot more void return values and a pile of deleted code
rsn.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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Re: [Nouveau] [PATCH] nouveau: no need to check return value of debugfs_create functions

[Greg Kroah-Hartman]

On Fri, Feb 14, 2020 at 12:30:48AM +0100, Daniel Vetter wrote:
> On Thu, Feb 13, 2020 at 11:39 PM Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> >
> > On Thu, Feb 13, 2020 at 02:30:09PM -0800, John Hubbard wrote:
> > > On 2/9/20 2:55 AM, Greg Kroah-Hartman wrote:
> > > > When calling debugfs functions, there is no need to ever check the
> > > > return value.  The function can work or not, but the code logic should
> > > > never do something different based on this.
> > > >
> > >
> > > Should we follow that line of reasoning further, and simply return void
> > > from the debugfs functions--rather than playing whack-a-mole with this
> > > indefinitely?
> >
> > That is what we (well I) have been doing.  Look at all of the changes
> > that have happened to include/linux/debugfs.h over the past few
> > releases.  I'm slowly winnowing down the api to make it impossible to
> > get wrong for this type of thing, and am almost there.
> >
> > DRM is the big fish left to tackle, I have submitted some patches in the
> > past, but lots more cleanup needs to be done to get them into mergable
> > shape.  I just need to find the time...
> 
> Just to avoid duplication, Wambui (cc'ed) just started working on
> this. Expect a lot more void return values and a pile of deleted code
> rsn.

Nice!

It's not duplication if I haven't started on it :)

greg k-h
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