From: Dan Carpenter <dan.carpenter@oracle.com>
To: Sergey Organov <sorganov@gmail.com>
Cc: Walter Harms <wharms@bfs.de>,
David Laight <David.Laight@ACULAB.COM>,
Joel Stanley <joel@jms.id.au>, Andrew Jeffery <andrew@aj.id.au>,
"Chia-Wei, Wang" <chiawei_wang@aspeedtech.com>,
Jae Hyun Yoo <jae.hyun.yoo@intel.com>,
John Wang <wangzhiqiang.bj@bytedance.com>,
Brad Bishop <bradleyb@fuzziesquirrel.com>,
Patrick Venture <venture@google.com>,
Benjamin Fair <benjaminfair@google.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Robert Lippert <rlippert@google.com>,
"linux-aspeed@lists.ozlabs.org" <linux-aspeed@lists.ozlabs.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kernel-janitors@vger.kernel.org"
<kernel-janitors@vger.kernel.org>
Subject: Re: AW: [PATCH] soc: aspeed: fix a ternary sign expansion bug
Date: Fri, 23 Apr 2021 18:24:59 +0300 [thread overview]
Message-ID: <20210423152459.GU1959@kadam> (raw)
In-Reply-To: <878s59rrn0.fsf@osv.gnss.ru>
On Fri, Apr 23, 2021 at 05:40:19PM +0300, Sergey Organov wrote:
> Walter Harms <wharms@bfs.de> writes:
>
> > as indepentent observer,
> > i would go for Dans solution:
> >
> > ret = kfifo_to_user();
> > /* if an error occurs just return */
> > if (ret)
> > return ret;
> >
> > /* otherwise return the copied number of bytes */
> >
> > return copied;
> >
> > there is no need for any deeper language knowledge,
>
> Yep, but this is not idiomatic C, so one looking at this code would
> tend to convert it back to ternary, and the actual problem here is that
> the type of 'copied' does not match the return type of the function.
>
I help maintain drivers/staging. I would hope that no one would send us
a patch like this because it's not a checkpatch or CodingStyle violation.
But people have sent us these before and Greg NAKs them because he
doesn't like ternaries. I NAK them because I like my success path kept
separate from the failure path. I want the success path indented one
tab and the failure path indented two tabs. I like when code is written
ploddingly, without fanciness, or combining multiple things on one line.
Using a ternary in this context seems to me like it falls under the
anti-pattern of "making the last call in a function weird". A lot of
times people change from failure handling to success handling for the
last function call.
err = one();
if (err)
goto fail;
err = two();
if (err)
goto fail;
err = three();
if (!err)
return 0;
goto fail:
print("failed!\n");
It seems crazy, but people do this all the time! It's fine to do:
return three();
There are some maintainers who insist that it should be:
err = three();
if (err)
return err;
return 0;
I don't go as far as that. But I also do like when I can glance at the
function and there is a giant "return 0;" at the bottom.
Anyway, if people change it back to ternary then the kbuild bot will
send them a warning message and they'll learn about an odd quirk in C's
type promotion rules.
regards,
dan carpenter
next prev parent reply other threads:[~2021-04-23 15:25 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-22 9:11 [PATCH] soc: aspeed: fix a ternary sign expansion bug Dan Carpenter
2021-04-22 9:24 ` Al Viro
2021-04-22 9:26 ` Al Viro
2021-04-22 14:56 ` Patrick Venture
2021-04-22 16:21 ` David Laight
2021-04-23 0:07 ` Joel Stanley
2021-04-23 7:43 ` Dan Carpenter
2021-04-23 10:45 ` Sergey Organov
2021-04-23 10:54 ` David Laight
2021-04-23 11:03 ` AW: " Walter Harms
2021-04-23 14:40 ` Sergey Organov
2021-04-23 14:55 ` David Laight
2021-04-23 15:24 ` Dan Carpenter [this message]
2021-04-23 11:14 ` Dan Carpenter
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=20210423152459.GU1959@kadam \
--to=dan.carpenter@oracle.com \
--cc=David.Laight@ACULAB.COM \
--cc=andrew@aj.id.au \
--cc=benjaminfair@google.com \
--cc=bradleyb@fuzziesquirrel.com \
--cc=chiawei_wang@aspeedtech.com \
--cc=gregkh@linuxfoundation.org \
--cc=jae.hyun.yoo@intel.com \
--cc=joel@jms.id.au \
--cc=kernel-janitors@vger.kernel.org \
--cc=linux-aspeed@lists.ozlabs.org \
--cc=linux-kernel@vger.kernel.org \
--cc=rlippert@google.com \
--cc=sorganov@gmail.com \
--cc=venture@google.com \
--cc=wangzhiqiang.bj@bytedance.com \
--cc=wharms@bfs.de \
/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).