2023-12-19 13:35:10

by Greg Kroah-Hartman

[permalink] [raw]
Subject: [PATCH] ALSA: mark all struct bus_type as const

Now that the driver core can properly handle constant struct bus_type,
move all of the sound subsystem struct bus_type structures as const,
placing them into read-only memory which can not be modified at runtime.

Note, this fixes a duplicate definition of ac97_bus_type, which somehow
was declared extern in a .h file, and then static as a prototype in a .c
file, and then properly later on in the same .c file. Amazing that no
compiler warning ever showed up for this.

Cc: Jaroslav Kysela <[email protected]>
Cc: Takashi Iwai <[email protected]>
Cc: Dawei Li <[email protected]>
Cc: Yu Liao <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Hans de Goede <[email protected]>
Cc: [email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
include/sound/ac97_codec.h | 2 +-
include/sound/hdaudio.h | 2 +-
sound/ac97/bus.c | 2 --
sound/ac97_bus.c | 2 +-
sound/hda/hda_bus_type.c | 2 +-
5 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/include/sound/ac97_codec.h b/include/sound/ac97_codec.h
index c495c6d5fbe0..4bd3be3a3192 100644
--- a/include/sound/ac97_codec.h
+++ b/include/sound/ac97_codec.h
@@ -410,7 +410,7 @@ int snd_ac97_pcm_close(struct ac97_pcm *pcm);
int snd_ac97_pcm_double_rate_rules(struct snd_pcm_runtime *runtime);

/* ad hoc AC97 device driver access */
-extern struct bus_type ac97_bus_type;
+extern const struct bus_type ac97_bus_type;

/* AC97 platform_data adding function */
static inline void snd_ac97_dev_add_pdata(struct snd_ac97 *ac97, void *data)
diff --git a/include/sound/hdaudio.h b/include/sound/hdaudio.h
index dd7c87bbc613..1517d752f750 100644
--- a/include/sound/hdaudio.h
+++ b/include/sound/hdaudio.h
@@ -33,7 +33,7 @@ struct hda_device_id;
/*
* exported bus type
*/
-extern struct bus_type snd_hda_bus_type;
+extern const struct bus_type snd_hda_bus_type;

/*
* generic arrays
diff --git a/sound/ac97/bus.c b/sound/ac97/bus.c
index 3173e9d98927..1dc7965eb14b 100644
--- a/sound/ac97/bus.c
+++ b/sound/ac97/bus.c
@@ -28,8 +28,6 @@ static DEFINE_MUTEX(ac97_controllers_mutex);
static DEFINE_IDR(ac97_adapter_idr);
static LIST_HEAD(ac97_controllers);

-static struct bus_type ac97_bus_type;
-
static inline struct ac97_controller*
to_ac97_controller(struct device *ac97_adapter)
{
diff --git a/sound/ac97_bus.c b/sound/ac97_bus.c
index c7aee8c42c55..7ea274c55900 100644
--- a/sound/ac97_bus.c
+++ b/sound/ac97_bus.c
@@ -75,7 +75,7 @@ int snd_ac97_reset(struct snd_ac97 *ac97, bool try_warm, unsigned int id,
}
EXPORT_SYMBOL_GPL(snd_ac97_reset);

-struct bus_type ac97_bus_type = {
+const struct bus_type ac97_bus_type = {
.name = "ac97",
};

diff --git a/sound/hda/hda_bus_type.c b/sound/hda/hda_bus_type.c
index 4cd94178df9f..cce2c30511a2 100644
--- a/sound/hda/hda_bus_type.c
+++ b/sound/hda/hda_bus_type.c
@@ -76,7 +76,7 @@ static int hda_uevent(const struct device *dev, struct kobj_uevent_env *env)
return 0;
}

-struct bus_type snd_hda_bus_type = {
+const struct bus_type snd_hda_bus_type = {
.name = "hdaudio",
.match = hda_bus_match,
.uevent = hda_uevent,
--
2.43.0



2023-12-30 09:13:33

by Takashi Iwai

[permalink] [raw]
Subject: Re: [PATCH] ALSA: mark all struct bus_type as const

On Tue, 19 Dec 2023 14:34:46 +0100,
Greg Kroah-Hartman wrote:
>
> Now that the driver core can properly handle constant struct bus_type,
> move all of the sound subsystem struct bus_type structures as const,
> placing them into read-only memory which can not be modified at runtime.
>
> Note, this fixes a duplicate definition of ac97_bus_type, which somehow
> was declared extern in a .h file, and then static as a prototype in a .c
> file, and then properly later on in the same .c file. Amazing that no
> compiler warning ever showed up for this.
>
> Cc: Jaroslav Kysela <[email protected]>
> Cc: Takashi Iwai <[email protected]>
> Cc: Dawei Li <[email protected]>
> Cc: Yu Liao <[email protected]>
> Cc: "Rafael J. Wysocki" <[email protected]>
> Cc: Hans de Goede <[email protected]>
> Cc: [email protected]
> Signed-off-by: Greg Kroah-Hartman <[email protected]>

Applied to for-next branch now. Thanks.


Takashi