linux-kernel - Re: [PATCH] tools/gpio: prevent resource leak

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Message-ID: <ZUzlh9M-w4ZITvGW@rigel>
Date:   Thu, 9 Nov 2023 21:58:31 +0800
From:   Kent Gibson <warthog618@...il.com>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     heminhong <heminhong@...inos.cn>, linus.walleij@...aro.org,
        brgl@...ev.pl, andy@...nel.org, linux-gpio@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] tools/gpio: prevent resource leak

On Thu, Nov 09, 2023 at 03:53:45PM +0200, Andy Shevchenko wrote:
> On Thu, Nov 9, 2023 at 2:36 PM Kent Gibson <warthog618@...il.com> wrote:
> >
> > On Thu, Nov 09, 2023 at 04:54:19PM +0800, heminhong wrote:
> > > In the main() function, the open() function is used to open the file.
> > > When the file is successfully opened, fd is used to interact with the file,
> > > but the fd is not closed, it will cause resource leak.
> > >
> >
> > All open files are automatically closed when a process exits.
> > That includes both those returned by open() and by the GPIO ioctls.
> > So explicitly closing them here before exiting is redundant.
>
> I would argue that this is a good practice for GPIO cases.
> More the GPIOs we have, the more line handles we can get, then default
> MAX open FD limit may occur. The best is to combine both.
>

That makes sense if the application is long lived and is continually
requesting and releasing resources, but that is not the case here - this
is a short lived app that makes a single request.
Note the "here" in my initial reply.

Cheers,
Kent.