![Takashi Iwai](/assets/img/avatar_default.png)
The OSS emulation in synth-emux helper has a potential AB/BA deadlock at the simultaneous closing and opening: close -> snd_seq_release() -> sne_seq_free_client() -> snd_seq_delete_all_ports(): takes client->ports_mutex -> port_delete() -> snd_emux_unuse(): takes emux->register_mutex open -> snd_seq_oss_open() -> snd_emux_open_seq_oss(): takes emux->register_mutex -> snd_seq_event_port_attach() -> snd_seq_create_port(): takes client->ports_mutex This patch addresses the deadlock by reducing the rance taking emux->register_mutex in snd_emux_open_seq_oss(). The lock is needed for the refcount handling, so move it locally. The calls in emux_seq.c are already with the mutex, thus they are replaced with the version without mutex lock/unlock. Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
417 lines
9 KiB
C
417 lines
9 KiB
C
/*
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* Midi Sequencer interface routines.
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*
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* Copyright (C) 1999 Steve Ratcliffe
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* Copyright (c) 1999-2000 Takashi Iwai <tiwai@suse.de>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include "emux_voice.h"
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#include <linux/slab.h>
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#include <linux/module.h>
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/* Prototypes for static functions */
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static void free_port(void *private);
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static void snd_emux_init_port(struct snd_emux_port *p);
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static int snd_emux_use(void *private_data, struct snd_seq_port_subscribe *info);
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static int snd_emux_unuse(void *private_data, struct snd_seq_port_subscribe *info);
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/*
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* MIDI emulation operators
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*/
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static struct snd_midi_op emux_ops = {
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snd_emux_note_on,
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snd_emux_note_off,
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snd_emux_key_press,
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snd_emux_terminate_note,
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snd_emux_control,
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snd_emux_nrpn,
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snd_emux_sysex,
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};
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/*
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* number of MIDI channels
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*/
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#define MIDI_CHANNELS 16
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/*
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* type flags for MIDI sequencer port
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*/
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#define DEFAULT_MIDI_TYPE (SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC |\
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SNDRV_SEQ_PORT_TYPE_MIDI_GM |\
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SNDRV_SEQ_PORT_TYPE_MIDI_GS |\
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SNDRV_SEQ_PORT_TYPE_MIDI_XG |\
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SNDRV_SEQ_PORT_TYPE_HARDWARE |\
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SNDRV_SEQ_PORT_TYPE_SYNTHESIZER)
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/*
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* Initialise the EMUX Synth by creating a client and registering
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* a series of ports.
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* Each of the ports will contain the 16 midi channels. Applications
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* can connect to these ports to play midi data.
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*/
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int
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snd_emux_init_seq(struct snd_emux *emu, struct snd_card *card, int index)
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{
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int i;
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struct snd_seq_port_callback pinfo;
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char tmpname[64];
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emu->client = snd_seq_create_kernel_client(card, index,
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"%s WaveTable", emu->name);
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if (emu->client < 0) {
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snd_printk(KERN_ERR "can't create client\n");
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return -ENODEV;
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}
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if (emu->num_ports < 0) {
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snd_printk(KERN_WARNING "seqports must be greater than zero\n");
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emu->num_ports = 1;
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} else if (emu->num_ports >= SNDRV_EMUX_MAX_PORTS) {
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snd_printk(KERN_WARNING "too many ports."
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"limited max. ports %d\n", SNDRV_EMUX_MAX_PORTS);
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emu->num_ports = SNDRV_EMUX_MAX_PORTS;
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}
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memset(&pinfo, 0, sizeof(pinfo));
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pinfo.owner = THIS_MODULE;
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pinfo.use = snd_emux_use;
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pinfo.unuse = snd_emux_unuse;
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pinfo.event_input = snd_emux_event_input;
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for (i = 0; i < emu->num_ports; i++) {
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struct snd_emux_port *p;
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sprintf(tmpname, "%s Port %d", emu->name, i);
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p = snd_emux_create_port(emu, tmpname, MIDI_CHANNELS,
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0, &pinfo);
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if (p == NULL) {
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snd_printk(KERN_ERR "can't create port\n");
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return -ENOMEM;
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}
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p->port_mode = SNDRV_EMUX_PORT_MODE_MIDI;
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snd_emux_init_port(p);
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emu->ports[i] = p->chset.port;
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emu->portptrs[i] = p;
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}
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return 0;
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}
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/*
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* Detach from the ports that were set up for this synthesizer and
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* destroy the kernel client.
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*/
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void
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snd_emux_detach_seq(struct snd_emux *emu)
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{
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if (emu->voices)
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snd_emux_terminate_all(emu);
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if (emu->client >= 0) {
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snd_seq_delete_kernel_client(emu->client);
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emu->client = -1;
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}
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}
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/*
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* create a sequencer port and channel_set
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*/
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struct snd_emux_port *
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snd_emux_create_port(struct snd_emux *emu, char *name,
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int max_channels, int oss_port,
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struct snd_seq_port_callback *callback)
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{
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struct snd_emux_port *p;
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int i, type, cap;
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/* Allocate structures for this channel */
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if ((p = kzalloc(sizeof(*p), GFP_KERNEL)) == NULL) {
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snd_printk(KERN_ERR "no memory\n");
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return NULL;
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}
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p->chset.channels = kcalloc(max_channels, sizeof(struct snd_midi_channel), GFP_KERNEL);
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if (p->chset.channels == NULL) {
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snd_printk(KERN_ERR "no memory\n");
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kfree(p);
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return NULL;
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}
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for (i = 0; i < max_channels; i++)
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p->chset.channels[i].number = i;
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p->chset.private_data = p;
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p->chset.max_channels = max_channels;
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p->emu = emu;
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p->chset.client = emu->client;
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#ifdef SNDRV_EMUX_USE_RAW_EFFECT
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snd_emux_create_effect(p);
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#endif
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callback->private_free = free_port;
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callback->private_data = p;
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cap = SNDRV_SEQ_PORT_CAP_WRITE;
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if (oss_port) {
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type = SNDRV_SEQ_PORT_TYPE_SPECIFIC;
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} else {
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type = DEFAULT_MIDI_TYPE;
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cap |= SNDRV_SEQ_PORT_CAP_SUBS_WRITE;
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}
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p->chset.port = snd_seq_event_port_attach(emu->client, callback,
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cap, type, max_channels,
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emu->max_voices, name);
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return p;
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}
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/*
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* release memory block for port
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*/
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static void
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free_port(void *private_data)
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{
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struct snd_emux_port *p;
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p = private_data;
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if (p) {
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#ifdef SNDRV_EMUX_USE_RAW_EFFECT
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snd_emux_delete_effect(p);
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#endif
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kfree(p->chset.channels);
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kfree(p);
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}
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}
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#define DEFAULT_DRUM_FLAGS (1<<9)
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/*
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* initialize the port specific parameters
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*/
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static void
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snd_emux_init_port(struct snd_emux_port *p)
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{
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p->drum_flags = DEFAULT_DRUM_FLAGS;
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p->volume_atten = 0;
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snd_emux_reset_port(p);
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}
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/*
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* reset port
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*/
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void
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snd_emux_reset_port(struct snd_emux_port *port)
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{
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int i;
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/* stop all sounds */
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snd_emux_sounds_off_all(port);
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snd_midi_channel_set_clear(&port->chset);
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#ifdef SNDRV_EMUX_USE_RAW_EFFECT
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snd_emux_clear_effect(port);
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#endif
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/* set port specific control parameters */
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port->ctrls[EMUX_MD_DEF_BANK] = 0;
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port->ctrls[EMUX_MD_DEF_DRUM] = 0;
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port->ctrls[EMUX_MD_REALTIME_PAN] = 1;
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for (i = 0; i < port->chset.max_channels; i++) {
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struct snd_midi_channel *chan = port->chset.channels + i;
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chan->drum_channel = ((port->drum_flags >> i) & 1) ? 1 : 0;
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}
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}
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/*
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* input sequencer event
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*/
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int
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snd_emux_event_input(struct snd_seq_event *ev, int direct, void *private_data,
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int atomic, int hop)
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{
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struct snd_emux_port *port;
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port = private_data;
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if (snd_BUG_ON(!port || !ev))
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return -EINVAL;
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snd_midi_process_event(&emux_ops, ev, &port->chset);
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return 0;
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}
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/*
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* increment usage count
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*/
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static int
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__snd_emux_inc_count(struct snd_emux *emu)
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{
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emu->used++;
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if (!try_module_get(emu->ops.owner))
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goto __error;
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if (!try_module_get(emu->card->module)) {
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module_put(emu->ops.owner);
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__error:
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emu->used--;
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return 0;
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}
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return 1;
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}
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int snd_emux_inc_count(struct snd_emux *emu)
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{
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int ret;
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mutex_lock(&emu->register_mutex);
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ret = __snd_emux_inc_count(emu);
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mutex_unlock(&emu->register_mutex);
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return ret;
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}
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/*
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* decrease usage count
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*/
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static void
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__snd_emux_dec_count(struct snd_emux *emu)
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{
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module_put(emu->card->module);
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emu->used--;
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if (emu->used <= 0)
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snd_emux_terminate_all(emu);
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module_put(emu->ops.owner);
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}
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void snd_emux_dec_count(struct snd_emux *emu)
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{
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mutex_lock(&emu->register_mutex);
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__snd_emux_dec_count(emu);
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mutex_unlock(&emu->register_mutex);
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}
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/*
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* Routine that is called upon a first use of a particular port
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*/
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static int
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snd_emux_use(void *private_data, struct snd_seq_port_subscribe *info)
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{
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struct snd_emux_port *p;
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struct snd_emux *emu;
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p = private_data;
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if (snd_BUG_ON(!p))
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return -EINVAL;
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emu = p->emu;
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if (snd_BUG_ON(!emu))
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return -EINVAL;
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mutex_lock(&emu->register_mutex);
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snd_emux_init_port(p);
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__snd_emux_inc_count(emu);
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mutex_unlock(&emu->register_mutex);
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return 0;
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}
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/*
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* Routine that is called upon the last unuse() of a particular port.
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*/
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static int
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snd_emux_unuse(void *private_data, struct snd_seq_port_subscribe *info)
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{
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struct snd_emux_port *p;
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struct snd_emux *emu;
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p = private_data;
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if (snd_BUG_ON(!p))
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return -EINVAL;
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emu = p->emu;
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if (snd_BUG_ON(!emu))
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return -EINVAL;
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mutex_lock(&emu->register_mutex);
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snd_emux_sounds_off_all(p);
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__snd_emux_dec_count(emu);
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mutex_unlock(&emu->register_mutex);
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return 0;
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}
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/*
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* attach virtual rawmidi devices
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*/
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int snd_emux_init_virmidi(struct snd_emux *emu, struct snd_card *card)
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{
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int i;
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emu->vmidi = NULL;
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if (emu->midi_ports <= 0)
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return 0;
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emu->vmidi = kcalloc(emu->midi_ports, sizeof(struct snd_rawmidi *), GFP_KERNEL);
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if (emu->vmidi == NULL)
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return -ENOMEM;
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for (i = 0; i < emu->midi_ports; i++) {
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struct snd_rawmidi *rmidi;
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struct snd_virmidi_dev *rdev;
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if (snd_virmidi_new(card, emu->midi_devidx + i, &rmidi) < 0)
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goto __error;
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rdev = rmidi->private_data;
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sprintf(rmidi->name, "%s Synth MIDI", emu->name);
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rdev->seq_mode = SNDRV_VIRMIDI_SEQ_ATTACH;
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rdev->client = emu->client;
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rdev->port = emu->ports[i];
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if (snd_device_register(card, rmidi) < 0) {
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snd_device_free(card, rmidi);
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goto __error;
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}
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emu->vmidi[i] = rmidi;
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/* snd_printk(KERN_DEBUG "virmidi %d ok\n", i); */
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}
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return 0;
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__error:
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/* snd_printk(KERN_DEBUG "error init..\n"); */
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snd_emux_delete_virmidi(emu);
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return -ENOMEM;
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}
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int snd_emux_delete_virmidi(struct snd_emux *emu)
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{
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int i;
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if (emu->vmidi == NULL)
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return 0;
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for (i = 0; i < emu->midi_ports; i++) {
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if (emu->vmidi[i])
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snd_device_free(emu->card, emu->vmidi[i]);
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}
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kfree(emu->vmidi);
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emu->vmidi = NULL;
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return 0;
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}
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