linux-kernel - Re: [PATCH] mtd: no need to check return value of debugfs

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Message-ID: <20191107091518.GA1328892@kroah.com>
Date:   Thu, 7 Nov 2019 10:15:18 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Miquel Raynal <miquel.raynal@...tlin.com>
Cc:     Brian Norris <computersforpeace@...il.com>,
        Marek Vasut <marek.vasut@...il.com>,
        Richard Weinberger <richard@....at>,
        Vignesh Raghavendra <vigneshr@...com>,
        Artem Bityutskiy <dedekind1@...il.com>,
        linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mtd: no need to check return value of debugfs_create
 functions

On Thu, Nov 07, 2019 at 10:09:44AM +0100, Miquel Raynal wrote:
> Hi Greg,
> 
> Greg Kroah-Hartman <gregkh@...uxfoundation.org> wrote on Thu, 7 Nov
> 2019 09:51:11 +0100:
> 
> > 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.
> 
> I didn't know about this. Is this something new or has it been the rule
> since the beginning? In the  case, don't we need a Fixes tag here?

It's been the way always, but as of a few kernel releases ago, debugfs
is even more "fault-tolerant" of stuff like this.

And there's no need for a "Fixes:" as this is just work to clean up the
debugfs api and usage (I have a lot more work to do after these types of
changes.)

> 
> > Cc: David Woodhouse <dwmw2@...radead.org>
> > Cc: Brian Norris <computersforpeace@...il.com>
> > Cc: Marek Vasut <marek.vasut@...il.com>
> > Cc: Miquel Raynal <miquel.raynal@...tlin.com>
> > Cc: Richard Weinberger <richard@....at>
> > Cc: Vignesh Raghavendra <vigneshr@...com>
> > Cc: Artem Bityutskiy <dedekind1@...il.com>
> > Cc: linux-mtd@...ts.infradead.org
> > Cc: linux-kernel@...r.kernel.org
> > Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> 
> [...]
> 
> > +
> > +	d->dfs_emulate_io_failures = debugfs_create_file("tst_emulate_io_failures",
> > +							 S_IWUSR, d->dfs_dir,
> > +							 (void *)ubi_num,
> > +							 &dfs_fops);
> > +
> > +	d->dfs_emulate_power_cut = debugfs_create_file("tst_emulate_power_cut",
> > +						       S_IWUSR, d->dfs_dir,
> > +						       (void *)ubi_num,
> > +						       &dfs_fops);
> 
> Nitpick: I think we miss an empty line here. I can fix it when applying.

Ah, oops, sorry about that.

thanks,

greg k-h