ALSA: seq: Constify struct snd_midi_op

Change the argument of snd_midi_process_event() to receive a const
snd_midi_op pointer and its callers respectively.  This allows further
optimizations.

There should be no functional changes by this patch.

Link: https://lore.kernel.org/r/20200103081714.9560-30-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

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);

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;
 

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,

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

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,

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,