linux-kernel - Re: [PATCH 1/4] lib/sprintf: add scnprintf

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Message-Id: <20251107161130.4418562992d2477c4accc6ef@linux-foundation.org>
Date: Fri, 7 Nov 2025 16:11:30 -0800
From: Andrew Morton <akpm@...ux-foundation.org>
To: David Laight <david.laight.linux@...il.com>
Cc: Junrui Luo <moonafterrain@...look.com>, linux-kernel@...r.kernel.org,
 pmladek@...e.com, rostedt@...dmis.org, andriy.shevchenko@...ux.intel.com,
 tiwai@...e.com, perex@...ex.cz, linux-sound@...r.kernel.org,
 mchehab@...nel.org, awalls@...metrocast.net, linux-media@...r.kernel.org,
 davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
 pabeni@...hat.com, netdev@...r.kernel.org
Subject: Re: [PATCH 1/4] lib/sprintf: add scnprintf_append() helper function

On Fri, 7 Nov 2025 09:12:46 +0000 David Laight <david.laight.linux@...il.com> wrote:

> > I wonder if we should instead implement a kasprintf() version of this
> > which reallocs each time and then switch all the callers over to that.
> 
> That adds the cost of a malloc, and I, like kasprintf() probably ends up
> doing all the work of snprintf twice.

There is no need at all to optimize the performance of scruffy once-off
string pasting functions.  For these it's better to optimize for
readability, reliability.  maintainability.