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sound: pcm: record a substream's owner process 

Record the pid of the task that opened a PCM substream. For sound
cards with hardware mixing, this allows determining which process
is associated with a specific substream's volume control.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Clemens Ladisch 2009-11-10 10:13:30 +01:00 committed by Takashi Iwai
parent 91d12c485b
commit e7373b702f
2 changed files with 7 additions and 0 deletions
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3
include/sound/pcm.h
View File

@ -348,6 +348,8 @@ struct snd_pcm_group { /* keep linked substreams */
int count;
};
struct pid;
struct snd_pcm_substream {
struct snd_pcm *pcm;
struct snd_pcm_str *pstr;
@ -379,6 +381,7 @@ struct snd_pcm_substream {
atomic_t mmap_count;
unsigned int f_flags;
void (*pcm_release)(struct snd_pcm_substream *);
struct pid *pid;
#if defined(CONFIG_SND_PCM_OSS) || defined(CONFIG_SND_PCM_OSS_MODULE)
/* -- OSS things -- */
struct snd_pcm_oss_substream oss;

4
sound/core/pcm.c
View File

@ -435,6 +435,7 @@ static void snd_pcm_substream_proc_status_read(struct snd_info_entry *entry,
return;
}
snd_iprintf(buffer, "state: %s\n", snd_pcm_state_name(status.state));
snd_iprintf(buffer, "owner_pid : %d\n", pid_vnr(substream->pid));
snd_iprintf(buffer, "trigger_time: %ld.%09ld\n",
status.trigger_tstamp.tv_sec, status.trigger_tstamp.tv_nsec);
snd_iprintf(buffer, "tstamp : %ld.%09ld\n",
@ -900,6 +901,7 @@ int snd_pcm_attach_substream(struct snd_pcm *pcm, int stream,
substream->private_data = pcm->private_data;
substream->ref_count = 1;
substream->f_flags = file->f_flags;
substream->pid = get_pid(task_pid(current));
pstr->substream_opened++;
*rsubstream = substream;
return 0;
@ -921,6 +923,8 @@ void snd_pcm_detach_substream(struct snd_pcm_substream *substream)
kfree(runtime->hw_constraints.rules);
kfree(runtime);
substream->runtime = NULL;
put_pid(substream->pid);
substream->pid = NULL;
substream->pstr->substream_opened--;
}