linux-kernel - Re: sound/pci/ctxfi/ctdaio.c: duplicate function removal question

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Message-ID: <87frm6dfda.wl-tiwai@suse.de>
Date: Sun, 29 Dec 2024 10:10:09 +0100
From: Takashi Iwai <tiwai@...e.de>
To: David Laight <david.laight.linux@...il.com>
Cc: Ethan Carter Edwards <ethan@...ancedwards.com>,
	"wychay@....creative.com" <wychay@....creative.com>,
	"ryan_richards@...ativelabs.com" <ryan_richards@...ativelabs.com>,
	"tiwai@...e.de" <tiwai@...e.de>,
	"linux-sound@...r.kernel.org"
 <linux-sound@...r.kernel.org>,
	"linux-kernel@...r.kernel.org"
 <linux-kernel@...r.kernel.org>
Subject: Re: sound/pci/ctxfi/ctdaio.c: duplicate function removal question

On Sun, 29 Dec 2024 10:02:28 +0100,
David Laight wrote:
> 
> On Tue, 24 Dec 2024 23:16:17 +0000
> Ethan Carter Edwards <ethan@...ancedwards.com> wrote:
> 
> > Hello all,
> > 
> > First of all, happy holidays. 
> > 
> > I was browsing the ctdaio.c code and I noticed a lot of 
> > duplicate code and functions, specifically:
> > 
> > dao_set_{right,left}_input and
> > dao_clear_{right,left}_input functions.
> > 
> > The functions are pretty much identical. They only 
> > differ in the side (left, right). What was the original
> > idea in doing this? Wouldn't it make more since to just
> > have an ENUM (left, right) as an argument that would 
> > determine the side and just reduce the function to 
> > dao_set_input and dao_clear_input.
> 
> Hmmm... you'd have a lot of conditionals inside the function.
> 
> They also look like a memory leak just waiting to happen.
> I guess that an earlier implementation used a separate kmalloc()
> for each imappers[].
> 
> Why is imappers[] an array of pointers not an array of the items?
> Each is just 8 bytes plus a 'list_head' (2 pointers?).

AFAIUC, it's a setup of a chained element, so no leak there as of
now.

I agree with that the code is unnecessarily complex, though.


thanks,

Takashi