[PATCH] ALSA: aloop: Constify ops structs

[PATCH] ALSA: aloop: Constify ops structs

[Rikard Falkeborn]

The only usage of the ops field in the loopback_cable struct is to call
its members, the field it self is never changed. Make it a pointer to
const. This allows us to constify two static loopback_ops structs to
allow the compiler to put them in read-only memory.

Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
---
 sound/drivers/aloop.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/sound/drivers/aloop.c b/sound/drivers/aloop.c
index c91356326699..702f91b9c60f 100644
--- a/sound/drivers/aloop.c
+++ b/sound/drivers/aloop.c
@@ -105,7 +105,7 @@ struct loopback_cable {
 	unsigned int running;
 	unsigned int pause;
 	/* timer specific */
-	struct loopback_ops *ops;
+	const struct loopback_ops *ops;
 	/* If sound timer is used */
 	struct {
 		int stream;
@@ -1021,7 +1021,7 @@ static int loopback_jiffies_timer_open(struct loopback_pcm *dpcm)
 	return 0;
 }
 
-static struct loopback_ops loopback_jiffies_timer_ops = {
+static const struct loopback_ops loopback_jiffies_timer_ops = {
 	.open = loopback_jiffies_timer_open,
 	.start = loopback_jiffies_timer_start,
 	.stop = loopback_jiffies_timer_stop,
@@ -1172,7 +1172,7 @@ static int loopback_snd_timer_open(struct loopback_pcm *dpcm)
 /* stop_sync() is not required for sound timer because it does not need to be
  * restarted in loopback_prepare() on Xrun recovery
  */
-static struct loopback_ops loopback_snd_timer_ops = {
+static const struct loopback_ops loopback_snd_timer_ops = {
 	.open = loopback_snd_timer_open,
 	.start = loopback_snd_timer_start,
 	.stop = loopback_snd_timer_stop,
-- 
2.29.2

Re: [PATCH] ALSA: aloop: Constify ops structs

[Takashi Iwai]

On Sat, 21 Nov 2020 00:10:46 +0100,
Rikard Falkeborn wrote:
> 
> The only usage of the ops field in the loopback_cable struct is to call
> its members, the field it self is never changed. Make it a pointer to
> const. This allows us to constify two static loopback_ops structs to
> allow the compiler to put them in read-only memory.
> 
> Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>

Thanks, applied.


Takashi