linux-kernel - Re: [PATCH 1/2] regmap: debugfs: remove bogus check

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Message-ID: <20150930172045.GE15635@sirena.org.uk>
Date:	Wed, 30 Sep 2015 18:20:45 +0100
From:	Mark Brown <broonie@...nel.org>
To:	Rasmus Villemoes <linux@...musvillemoes.dk>
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] regmap: debugfs: remove bogus check

On Wed, Sep 30, 2015 at 09:27:38AM +0200, Rasmus Villemoes wrote:

> I agree, but only on the word 'great'. There is value in removing such
> bogosities (or rather, their presence provides negative value). It makes
> the code harder to read ("why is this instance checked, but not any of
> the other snprintfs?"); people may think that it's trying to check for
> truncation, but it does no such thing; and it contributes a few
> worthless bytes to .text (and the source).

The solution to partial error checking isn't always to remove the error
checking!

> If you're worried about map->dev->driver->name actually ever being > 2G,
> returning some almost totally random negative number isn't really
> helpful (the function is supposed to return a -errno). And what makes
> you think that in some hypothetical universe where the kernel's snprintf
> explicit returns a negative value that it wouldn't just return -1 (aka
> -EPERM)?

This is going back to the discussion about having to learn the specific
snprinf() implementation one is dealing with.

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