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 <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Dawei Li <set_pte_at@outlook.com>
Cc: Yu Liao <liaoyu15@huawei.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: linux-sound@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/2023121945-immersion-budget-d0aa@gregkh
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 1 insertions, 1 deletions

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",
 };