linux-kernel - Object code duplication in sound/pci/echoaudio/

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Date:	Mon, 11 May 2015 22:15:28 +0200
From:	Denys Vlasenko <dvlasenk@...hat.com>
To:	Giuliano Pochini <pochini@...ny.it>, Takashi Iwai <tiwai@...e.de>,
	Jaroslav Kysela <perex@...e.cz>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Object code duplication in sound/pci/echoaudio/

There are fourteen files in sound/pci/echoaudio/, namely:

darla20.c darla24.c echo3g.c gina20.c gina24.c indigo.c
indigodj.c indigodjx.c indigoio.c indigoiox.c layla20.c
layla24.c mia.c mona.c

Which use the following method of "code reuse":

#include "echoaudio_dsp.c"
#include "echoaudio_gml.c"
#include "echoaudio.c"

echoaudio.c is not a header file, it contains a bunch of
static functions, some of a considerable size.
This makes those functions to be duplicated many times over.

For instance, there are fourteen instances of init_engine(),
each 1117 bytes long. Fourteen instances of pcm_open(), each 556 bytes
long.

11 get_firmware
10 free_firmware
13 audiopipe_free
14 init_hw
14 hw_rule_capture_format_by_channels
14 hw_rule_capture_channels_by_format
14 hw_rule_playback_format_by_channels
14 hw_rule_playback_channels_by_format

and so on.

In my humble opinion, this is not a good coding practice.
You should not duplicate functions like this.
Where possible, you need to reuse a single instance of a function.

According to git, author of these drivers is Giuliano Pochini
<pochini@...ny.it>.
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