ALSA: seq: Use flexible array for MIDI channels

Store MIDI channel entries in the MIDI channel set allocation instead
of allocating them separately.

This ties the channel array lifetime directly to the channel set, removes
a separate allocation failure path, and lets __counted_by() describe the
array bounds. Move the embedded emux channel set to the end of its
containing structure so it can carry the flexible array.

Assisted-by: Codex:GPT-5.5
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Link: https://patch.msgid.link/20260511075447.445350-1-rosenp@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/include/sound/emux_synth.h b/include/sound/emux_synth.h
index 3f7f365ed248cd82c0fd96c0414ccfdc2c4079ae..2c0a976e00abb4d20b94fd4df64cec370a29333e 100644 (file)
--- a/include/sound/emux_synth.h
+++ b/include/sound/emux_synth.h
@@ -125,7 +125,6 @@ struct snd_emux {
  */
 struct snd_emux_port {
 
-       struct snd_midi_channel_set chset;
        struct snd_emux *emu;
 
        char port_mode;                 /* operation mode */
@@ -138,6 +137,7 @@ struct snd_emux_port {
 #if IS_ENABLED(CONFIG_SND_SEQUENCER_OSS)
        struct snd_seq_oss_arg *oss_arg;
 #endif
+       struct snd_midi_channel_set chset;
 };
 
 /* port_mode */

diff --git a/include/sound/seq_midi_emul.h b/include/sound/seq_midi_emul.h
index 88799d1e1f53dfb695919241576213700757fa9f..afc7654378701e0f00ecf40320e53ce624f1fd93 100644 (file)
--- a/include/sound/seq_midi_emul.h
+++ b/include/sound/seq_midi_emul.h
@@ -55,14 +55,14 @@ struct snd_midi_channel_set {
        int  client;                    /* Client for this port */
        int  port;                      /* The port number */
 
-       int  max_channels;              /* Size of the channels array */
-       struct snd_midi_channel *channels;
-
        unsigned char midi_mode;        /* MIDI operating mode */
        unsigned char gs_master_volume; /* SYSEX master volume: 0-127 */
        unsigned char gs_chorus_mode;
        unsigned char gs_reverb_mode;
 
+       int  max_channels;              /* Size of the channels array */
+       struct snd_midi_channel channels[] __counted_by(max_channels);
+
 };
 
 struct snd_midi_op {

diff --git a/sound/core/seq/seq_midi_emul.c b/sound/core/seq/seq_midi_emul.c
index fd067c85c524fcdc566fba1fc62bd8c4a151e657..a90ebc7b3811b24fc0aabf78698bdd0367d0860e 100644 (file)
--- a/sound/core/seq/seq_midi_emul.c
+++ b/sound/core/seq/seq_midi_emul.c
@@ -81,9 +81,6 @@ snd_midi_process_event(const struct snd_midi_op *ops,
                pr_debug("ALSA: seq_midi_emul: ev or chanbase NULL (snd_midi_process_event)\n");
                return;
        }
-       if (chanset->channels == NULL)
-               return;
-
        if (snd_seq_ev_is_channel_type(ev)) {
                dest_channel = ev->data.note.channel;
                if (dest_channel >= chanset->max_channels) {
@@ -642,23 +639,6 @@ static void snd_midi_channel_init(struct snd_midi_channel *p, int n)
                p->drum_channel = 1;    /* Default ch 10 as drums */
 }
 
-/*
- * Allocate and initialise a set of midi channel control blocks.
- */
-static struct snd_midi_channel *snd_midi_channel_init_set(int n)
-{
-       struct snd_midi_channel *chan;
-       int  i;
-
-       chan = kmalloc_objs(struct snd_midi_channel, n);
-       if (chan) {
-               for (i = 0; i < n; i++)
-                       snd_midi_channel_init(chan+i, i);
-       }
-
-       return chan;
-}
-
 /*
  * reset all midi channels
  */
@@ -687,13 +667,18 @@ reset_all_channels(struct snd_midi_channel_set *chset)
 struct snd_midi_channel_set *snd_midi_channel_alloc_set(int n)
 {
        struct snd_midi_channel_set *chset;
+       int i;
+
+       chset = kmalloc_flex(*chset, channels, n);
+       if (!chset)
+               return NULL;
+
+       chset->max_channels = n;
+       chset->private_data = NULL;
+
+       for (i = 0; i < n; i++)
+               snd_midi_channel_init(&chset->channels[i], i);
 
-       chset = kmalloc_obj(*chset);
-       if (chset) {
-               chset->channels = snd_midi_channel_init_set(n);
-               chset->private_data = NULL;
-               chset->max_channels = n;
-       }
        return chset;
 }
 EXPORT_SYMBOL(snd_midi_channel_alloc_set);
@@ -717,7 +702,6 @@ void snd_midi_channel_free_set(struct snd_midi_channel_set *chset)
 {
        if (chset == NULL)
                return;
-       kfree(chset->channels);
        kfree(chset);
 }
 EXPORT_SYMBOL(snd_midi_channel_free_set);

diff --git a/sound/synth/emux/emux_seq.c b/sound/synth/emux/emux_seq.c
index 2ed01e9d79bb9057142baafa7625db0c3d054077..01ad5b12b680f5d13b018795f7ab8f92088e4c4a 100644 (file)
--- a/sound/synth/emux/emux_seq.c
+++ b/sound/synth/emux/emux_seq.c
@@ -132,19 +132,15 @@ snd_emux_create_port(struct snd_emux *emu, char *name,
        int i, type, cap;
 
        /* Allocate structures for this channel */
-       p = kzalloc_obj(*p);
+       p = kzalloc_flex(*p, chset.channels, max_channels);
        if (!p)
                return NULL;
 
-       p->chset.channels = kzalloc_objs(*p->chset.channels, max_channels);
-       if (!p->chset.channels) {
-               kfree(p);
-               return NULL;
-       }
+       p->chset.max_channels = max_channels;
+
        for (i = 0; i < max_channels; i++)
                p->chset.channels[i].number = i;
        p->chset.private_data = p;
-       p->chset.max_channels = max_channels;
        p->emu = emu;
        p->chset.client = emu->client;
 #ifdef SNDRV_EMUX_USE_RAW_EFFECT
@@ -182,7 +178,6 @@ free_port(void *private_data)
 #ifdef SNDRV_EMUX_USE_RAW_EFFECT
                snd_emux_delete_effect(p);
 #endif
-               kfree(p->chset.channels);
                kfree(p);
        }
 }