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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jirislaby@kernel.org>,
	Vignesh Raghavendra <vigneshr@ti.com>,
	Alexander Sverdlin <alexander.sverdlin@gmail.com>,
	Johan Hovold <johan@kernel.org>,
	linux-serial@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] serial: 8250_omap: fix a timeout loop condition
Date: Fri, 30 Apr 2021 17:21:24 +0300	[thread overview]
Message-ID: <YIwSZGE76f2ZJyyf@smile.fi.intel.com> (raw)
In-Reply-To: <20210430133329.GH1981@kadam>

On Fri, Apr 30, 2021 at 04:33:29PM +0300, Dan Carpenter wrote:
> On Fri, Apr 30, 2021 at 03:53:44PM +0300, Andy Shevchenko wrote:
> > On Fri, Apr 30, 2021 at 02:41:06PM +0300, Dan Carpenter wrote:
> > > On Fri, Apr 30, 2021 at 11:46:07AM +0300, Andy Shevchenko wrote:

...

> > > Why would I make it unsigned?  As a static analysis developer,
> > > pointlessly unsigned variables are one of the leading causes for the
> > > bugs I see.
> > > 
> > > There are times where a iterator counter needs to be unsigned long, or
> > > u64 but I have never seen a case where changing an iterator from
> > > "int i;" to "unsigned int i;" solves a real life kernel bug.  It only
> > > introduces bugs.
> > 
> > See my followup to that, I meant
> > 
> > unsigned int count;
> > 
> > do {
> > 	...
> > } while (--count);
> > 
> > It doesn't solve bug, but prevents the code be read incorrectly like what you
> > are fixing can be avoided with do {} while (); along with unsigned type.
> 
> Why would you use an unsigned int for this???

Why it should be signed? You clearly show the amount of iterations. Check for
null I guess even compact in the assembly in comparison to -1.

I do not see any point why it should be signed. For what purpose?

It's a *down* counter.

-- 
With Best Regards,
Andy Shevchenko



  reply	other threads:[~2021-04-30 14:22 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-29  7:19 [PATCH] serial: 8250_omap: fix a timeout loop condition Dan Carpenter
2021-04-29  9:23 ` Alexander Sverdlin
2021-04-29 11:08 ` Andy Shevchenko
2021-04-29 13:02   ` Dan Carpenter
2021-04-30  8:46     ` Andy Shevchenko
2021-04-30  8:47       ` Andy Shevchenko
2021-04-30 11:41       ` Dan Carpenter
2021-04-30 12:53         ` Andy Shevchenko
2021-04-30 13:33           ` Dan Carpenter
2021-04-30 14:21             ` Andy Shevchenko [this message]
2021-05-03  6:54               ` Dan Carpenter
2021-05-03  9:51                 ` Andy Shevchenko
2021-05-14  8:00                   ` Dan Carpenter

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