Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Mon, 24 May 2021 11:51:42 +0200 | Subject | Re: [PATCH] debugfs: remove return value of debugfs_create_bool() |
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Hi Greg,
On Mon, May 24, 2021 at 11:41 AM Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > On Mon, May 24, 2021 at 11:11:32AM +0200, Geert Uytterhoeven wrote: > > On Fri, May 21, 2021 at 10:28 PM Greg Kroah-Hartman > > <gregkh@linuxfoundation.org> wrote: > > > No one checks the return value of debugfs_create_bool(), as it's not > > > needed, so make the return value void, so that no one tries to do so in > > > > Please explain in the patch description why it is not needed. > > Because you just do not need it, like almost all other debugfs calls > now.
Why do I just not need it?
> > > the future. > > > > > > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > > > > > --- a/fs/debugfs/file.c > > > +++ b/fs/debugfs/file.c > > > @@ -836,20 +836,11 @@ static const struct file_operations fops_bool_wo = { > > > * This function creates a file in debugfs with the given name that > > > * contains the value of the variable @value. If the @mode variable is so > > > * set, it can be read from, and written to. > > > - * > > > - * This function will return a pointer to a dentry if it succeeds. This > > > - * pointer must be passed to the debugfs_remove() function when the file is > > > - * to be removed (no automatic cleanup happens if your module is unloaded, > > > > Why isn't the above no longer true? > > Because there is no return value.
Why is there no longer a return value? Please stop giving circular answers as justifications.
> > Are we no longer allowed to remove individual debugfs entries? > > It's not something that is almost ever needed.
Why not?
> > Do we always have to remove the whole parent directory and all its > > contents together? > > For 99% of all debugfs usages, yes, that is true.
So 1% of the users still need it...
> If you really do need the file dentry, there is still a call to create > it, and you can always query debugfs for the dentry after it is created
... and will have to duplicate debugfs_create_bool() and friends, but with a return value. This may introduce bugs, and will complicate maintenance, as any change to debugfs_create_bool() means all those copies need to be found and updated, too.
> if you need it later on.
Which involves looking up something again...
Seriously, what's the added value of removing the return value from debugfs_create_bool() and friends?
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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