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Date: Fri, 12 Apr 2024 20:53:03 +0300
From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= <u.kleine-koenig@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Raag Jadav <raag.jadav@intel.com>, linux-kernel@vger.kernel.org,
	kernel@pengutronix.de, "Rafael J. Wysocki" <rafael@kernel.org>
Subject: Re: [PATCH] driver core: Make dev_err_probe() silent for -ENOMEM
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On Fri, Apr 12, 2024 at 07:47:43PM +0200, Uwe Kleine-K?nig wrote:
> On Fri, Apr 12, 2024 at 08:07:29PM +0300, Andy Shevchenko wrote:
> > On Fri, Apr 12, 2024 at 07:03:01PM +0200, Uwe Kleine-K?nig wrote:
> > > On Fri, Apr 12, 2024 at 07:51:48PM +0300, Andy Shevchenko wrote:
> > > > On Fri, Apr 12, 2024 at 06:44:05PM +0200, Uwe Kleine-K?nig wrote:
> > > > > For an out-of-memory error there should be no additional output. Adapt
> > > > > dev_err_probe() to not emit the error message when err is -ENOMEM.
> > > > > This simplifies handling errors that might among others be -ENOMEM.

..

> > > > 	BUILD_BUG_ON(err == -ENOMEM);
> > > > 
> > > > Done!
> > > 
> > > Well no, that doesn't do the trick. Consider for example device_add().
> > > That function can return (at least) -EINVAL and -ENOMEM. To properly
> > > ensure that the error handling is silent with the current
> > > dev_err_probe(), we'd need to do:
> > > 
> > > 	ret = device_add(...);
> > > 	if (ret) {
> > > 		if (ret != -ENOMEM)
> > > 			return dev_err_probe(...);
> > > 		else
> > > 			return ret;
> > > 	}
> > > 
> > > With my suggested patch this can be reduced to:
> > > 
> > > 	ret = device_add(...);
> > > 	if (ret)
> > > 		return dev_err_probe(...);
> > 
> > Fair enough, but these two should be combined.
> > Mine is for the rejecting a dead code on the phase of the submission.
> 
> So something like the following on top of my change (only compile
> tested):

Hmm, but why macro? Shouldn't compiler be clever enough to see it even for
the exported function?

..

> I don't know if the kernel doc for dev_err_probe() should move to
> include/linux/dev_printk.h then?!

Not if you mark it for the __ variant.

But it has other kernel-doc formatting issues...

-- 
With Best Regards,
Andy Shevchenko