linux-kernel - Re: [PATCH][next] mips: sgi-ip22: Replace "s[n]?printf" with sysfs

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Message-ID: <ZxDRmlDbtjEaTH8z@mail.google.com>
Date: Thu, 17 Oct 2024 21:58:02 +1300
From: Paulo Miguel Almeida <paulo.miguel.almeida.rodenas@...il.com>
To: "Maciej W. Rozycki" <macro@...am.me.uk>
Cc: Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	zhanggenjian@...inos.cn, ricardo@...liere.net, bvanassche@....org,
	linux-mips@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-hardening@...r.kernel.org
Subject: Re: [PATCH][next] mips: sgi-ip22: Replace "s[n]?printf" with
 sysfs_emit in sysfs callbacks

On Tue, Oct 15, 2024 at 03:01:13AM +0100, Maciej W. Rozycki wrote:
> On Tue, 15 Oct 2024, Paulo Miguel Almeida wrote:
> 
> > snprintf() has the documented, but still rather strange trait of
> > returning the length of the data that *would have been* written to the
> > array if space were available, rather than the arguably more useful
> > length of data *actually* written, [...]
> 
>  Why do you think that just returning `n - 1' in the case of a length 
> overflow would be more useful than returning the unmet buffer length 
> requirement?  I think the opposite is the case: the value returned lets 
> you reallocate the buffer for more space and retry, and there's no other 
> way to figure out how much this would be.  And if you need to know how 
> many characters were actually written, then `min(n - 1, snprintf(...))' 
> will do (and code you propose to replace does exactly that, open-coded).
> 
>  The change itself makes sense to me, but not your proposed description 
> I'm afraid.  Just replacing open-coded pieces with calls to `sysfs_emit' 
> is enough justification.
> 
>   Maciej

Thanks for taking the time to review this patch.

Will submit a v2 with the description you pointed out.

- Paulo A.