diff --git a/include/sound/seq_midi_emul.h b/include/sound/seq_midi_emul.h
index d6b74059b4b1984f1f168526350b55f0b04b450b..88799d1e1f53dfb695919241576213700757fa9f 100644
--- a/include/sound/seq_midi_emul.h
+++ b/include/sound/seq_midi_emul.h
@@ -174,7 +174,8 @@ enum {
};
/* Prototypes for midi_process.c */
-void snd_midi_process_event(struct snd_midi_op *ops, struct snd_seq_event *ev,
+void snd_midi_process_event(const struct snd_midi_op *ops,
+ struct snd_seq_event *ev,
struct snd_midi_channel_set *chanset);
void snd_midi_channel_set_clear(struct snd_midi_channel_set *chset);
struct snd_midi_channel_set *snd_midi_channel_alloc_set(int n);
diff --git a/sound/core/seq/seq_midi_emul.c b/sound/core/seq/seq_midi_emul.c
index 770d3f4eee7cd47b59a5ee75ef218e4e71adc532..536ccf48ee72563445ed9e5e492e5360a39f8f88 100644
--- a/sound/core/seq/seq_midi_emul.c
+++ b/sound/core/seq/seq_midi_emul.c
@@ -30,22 +30,25 @@ MODULE_DESCRIPTION("Advanced Linux Sound Architecture sequencer MIDI emulation."
MODULE_LICENSE("GPL");
/* Prototypes for static functions */
-static void note_off(struct snd_midi_op *ops, void *drv,
+static void note_off(const struct snd_midi_op *ops, void *drv,
struct snd_midi_channel *chan,
int note, int vel);
-static void do_control(struct snd_midi_op *ops, void *private,
+static void do_control(const struct snd_midi_op *ops, void *private,
struct snd_midi_channel_set *chset,
struct snd_midi_channel *chan,
int control, int value);
-static void rpn(struct snd_midi_op *ops, void *drv, struct snd_midi_channel *chan,
+static void rpn(const struct snd_midi_op *ops, void *drv,
+ struct snd_midi_channel *chan,
struct snd_midi_channel_set *chset);
-static void nrpn(struct snd_midi_op *ops, void *drv, struct snd_midi_channel *chan,
+static void nrpn(const struct snd_midi_op *ops, void *drv,
+ struct snd_midi_channel *chan,
struct snd_midi_channel_set *chset);
-static void sysex(struct snd_midi_op *ops, void *private, unsigned char *sysex,
+static void sysex(const struct snd_midi_op *ops, void *private,
+ unsigned char *sysex,
int len, struct snd_midi_channel_set *chset);
-static void all_sounds_off(struct snd_midi_op *ops, void *private,
+static void all_sounds_off(const struct snd_midi_op *ops, void *private,
struct snd_midi_channel *chan);
-static void all_notes_off(struct snd_midi_op *ops, void *private,
+static void all_notes_off(const struct snd_midi_op *ops, void *private,
struct snd_midi_channel *chan);
static void snd_midi_reset_controllers(struct snd_midi_channel *chan);
static void reset_all_channels(struct snd_midi_channel_set *chset);
@@ -66,7 +69,7 @@ static void reset_all_channels(struct snd_midi_channel_set *chset);
* be interpreted.
*/
void
-snd_midi_process_event(struct snd_midi_op *ops,
+snd_midi_process_event(const struct snd_midi_op *ops,
struct snd_seq_event *ev,
struct snd_midi_channel_set *chanset)
{
@@ -229,7 +232,8 @@ EXPORT_SYMBOL(snd_midi_process_event);
* release note
*/
static void
-note_off(struct snd_midi_op *ops, void *drv, struct snd_midi_channel *chan,
+note_off(const struct snd_midi_op *ops, void *drv,
+ struct snd_midi_channel *chan,
int note, int vel)
{
if (chan->gm_hold) {
@@ -251,7 +255,8 @@ note_off(struct snd_midi_op *ops, void *drv, struct snd_midi_channel *chan,
* events that need to take place immediately to the driver.
*/
static void
-do_control(struct snd_midi_op *ops, void *drv, struct snd_midi_channel_set *chset,
+do_control(const struct snd_midi_op *ops, void *drv,
+ struct snd_midi_channel_set *chset,
struct snd_midi_channel *chan, int control, int value)
{
int i;
@@ -402,7 +407,7 @@ EXPORT_SYMBOL(snd_midi_channel_set_clear);
* Process a rpn message.
*/
static void
-rpn(struct snd_midi_op *ops, void *drv, struct snd_midi_channel *chan,
+rpn(const struct snd_midi_op *ops, void *drv, struct snd_midi_channel *chan,
struct snd_midi_channel_set *chset)
{
int type;
@@ -442,7 +447,7 @@ rpn(struct snd_midi_op *ops, void *drv, struct snd_midi_channel *chan,
* Process an nrpn message.
*/
static void
-nrpn(struct snd_midi_op *ops, void *drv, struct snd_midi_channel *chan,
+nrpn(const struct snd_midi_op *ops, void *drv, struct snd_midi_channel *chan,
struct snd_midi_channel_set *chset)
{
/* parse XG NRPNs here if possible */
@@ -470,7 +475,7 @@ get_channel(unsigned char cmd)
* Process a sysex message.
*/
static void
-sysex(struct snd_midi_op *ops, void *private, unsigned char *buf, int len,
+sysex(const struct snd_midi_op *ops, void *private, unsigned char *buf, int len,
struct snd_midi_channel_set *chset)
{
/* GM on */
@@ -584,7 +589,8 @@ sysex(struct snd_midi_op *ops, void *private, unsigned char *buf, int len,
* all sound off
*/
static void
-all_sounds_off(struct snd_midi_op *ops, void *drv, struct snd_midi_channel *chan)
+all_sounds_off(const struct snd_midi_op *ops, void *drv,
+ struct snd_midi_channel *chan)
{
int n;
@@ -602,7 +608,8 @@ all_sounds_off(struct snd_midi_op *ops, void *drv, struct snd_midi_channel *chan
* all notes off
*/
static void
-all_notes_off(struct snd_midi_op *ops, void *drv, struct snd_midi_channel *chan)
+all_notes_off(const struct snd_midi_op *ops, void *drv,
+ struct snd_midi_channel *chan)
{
int n;
diff --git a/sound/drivers/opl3/opl3_seq.c b/sound/drivers/opl3/opl3_seq.c
index 20f2f512539439a836aa711902d18ac576dc085e..cd2a01b5e2e134dd1199af216491d3241e6d6244 100644
--- a/sound/drivers/opl3/opl3_seq.c
+++ b/sound/drivers/opl3/opl3_seq.c
@@ -128,7 +128,7 @@ static int snd_opl3_synth_unuse(void *private_data, struct snd_seq_port_subscrib
/*
* MIDI emulation operators
*/
-struct snd_midi_op opl3_ops = {
+const struct snd_midi_op opl3_ops = {
.note_on = snd_opl3_note_on,
.note_off = snd_opl3_note_off,
.key_press = snd_opl3_key_press,
diff --git a/sound/drivers/opl3/opl3_voice.h b/sound/drivers/opl3/opl3_voice.h
index dc0626a2dd61a8f00847ef34077fbeddef1a9668..be9ccca2d95237fe72d55f0fd1cfee79da3cc4f7 100644
--- a/sound/drivers/opl3/opl3_voice.h
+++ b/sound/drivers/opl3/opl3_voice.h
@@ -41,6 +41,6 @@ void snd_opl3_free_seq_oss(struct snd_opl3 *opl3);
extern char snd_opl3_regmap[MAX_OPL2_VOICES][4];
extern bool use_internal_drums;
-extern struct snd_midi_op opl3_ops;
+extern const struct snd_midi_op opl3_ops;
#endif
diff --git a/sound/drivers/opl4/opl4_seq.c b/sound/drivers/opl4/opl4_seq.c
index 03d6202f482931ed4c9aeab5808bec0457aab23a..f59ca660c6164e0019e284c2172e02f892e0ce6e 100644
--- a/sound/drivers/opl4/opl4_seq.c
+++ b/sound/drivers/opl4/opl4_seq.c
@@ -100,7 +100,7 @@ static int snd_opl4_seq_unuse(void *private_data, struct snd_seq_port_subscribe
return 0;
}
-static struct snd_midi_op opl4_ops = {
+static const struct snd_midi_op opl4_ops = {
.note_on = snd_opl4_note_on,
.note_off = snd_opl4_note_off,
.note_terminate = snd_opl4_terminate_note,
diff --git a/sound/synth/emux/emux_seq.c b/sound/synth/emux/emux_seq.c
index 9d8a69f1a644e52bb3224e434e5048d58a1728ea..b227c7e0bc2ac91fb13553e692fcd77002345125 100644
--- a/sound/synth/emux/emux_seq.c
+++ b/sound/synth/emux/emux_seq.c
@@ -19,7 +19,7 @@ static int snd_emux_unuse(void *private_data, struct snd_seq_port_subscribe *inf
/*
* MIDI emulation operators
*/
-static struct snd_midi_op emux_ops = {
+static const struct snd_midi_op emux_ops = {
.note_on = snd_emux_note_on,
.note_off = snd_emux_note_off,
.key_press = snd_emux_key_press,