From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Alessandro Rubini <rubini@gnudd.com>,
Michal.Vokac@ysoft.com, corbet@lwn.net,
gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
thierry.reding@gmail.com, kernel@pengutronix.de,
akpm@linux-foundation.org
Subject: Re: [PATCH RFC] err.h: document that PTR_ERR should only be used if IS_ERR returns true
Date: Tue, 16 Oct 2018 21:29:28 +0200 [thread overview]
Message-ID: <20181016192928.pinjwxfors4reigh@pengutronix.de> (raw)
In-Reply-To: <20181016180650.GZ32577@ZenIV.linux.org.uk>
On Tue, Oct 16, 2018 at 07:06:51PM +0100, Al Viro wrote:
> On Mon, Oct 15, 2018 at 11:37:08AM +0200, Alessandro Rubini wrote:
>
> > OTOH I admit you can compare any value with -EINVAL, after PTR_ERR.
> > But in general you first detect the error condition and then split
> > among error (or print a message according to the exact value.
>
> if (IS_ERR(p) && PTR_ERR(p) == -ENOENT)
> instead of
> if (p == ERR_PTR(-ENOENT))
>
> is ugly, obfuscating what's going on for no good reason and I'm going
> to keep killing those every time I run into one...
And what do you do if you see a
p = somefunc(...);
if (PTR_ERR(p) == -ENOENT)
without first checking for IS_ERR(p)? Another alternative is
if (PTR_ERR_OR_ZERO(p) == -ENOENT)
? In your eyes, should they all be converted to
if (p == ERR_PTR(-ENOENT))
?
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
next prev parent reply other threads:[~2018-10-16 19:29 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-14 20:28 [PATCH RFC] err.h: document that PTR_ERR should only be used if IS_ERR returns true Uwe Kleine-König
2018-10-15 9:37 ` Alessandro Rubini
2018-10-15 9:46 ` Uwe Kleine-König
2018-10-16 18:06 ` Al Viro
2018-10-16 19:29 ` Uwe Kleine-König [this message]
2018-10-16 20:10 ` Alessandro Rubini
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20181016192928.pinjwxfors4reigh@pengutronix.de \
--to=u.kleine-koenig@pengutronix.de \
--cc=Michal.Vokac@ysoft.com \
--cc=akpm@linux-foundation.org \
--cc=corbet@lwn.net \
--cc=gregkh@linuxfoundation.org \
--cc=kernel@pengutronix.de \
--cc=linux-kernel@vger.kernel.org \
--cc=rubini@gnudd.com \
--cc=thierry.reding@gmail.com \
--cc=viro@ZenIV.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).