From cb02416507bc0c31415f1527aefc280ae96260bd Mon Sep 17 00:00:00 2001 From: Rosen Penev Date: Mon, 11 May 2026 00:54:47 -0700 Subject: [PATCH] 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 Link: https://patch.msgid.link/20260511075447.445350-1-rosenp@gmail.com Signed-off-by: Takashi Iwai --- include/sound/emux_synth.h | 2 +- include/sound/seq_midi_emul.h | 6 +++--- sound/core/seq/seq_midi_emul.c | 38 ++++++++++------------------------ sound/synth/emux/emux_seq.c | 11 +++------- 4 files changed, 18 insertions(+), 39 deletions(-) diff --git a/include/sound/emux_synth.h b/include/sound/emux_synth.h index 3f7f365ed248..2c0a976e00ab 100644 --- 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 88799d1e1f53..afc765437870 100644 --- 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 fd067c85c524..a90ebc7b3811 100644 --- 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 2ed01e9d79bb..01ad5b12b680 100644 --- 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); } }