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>
diff --git a/include/sound/pcm.h b/include/sound/pcm.h
index de6d981..c83a4a7 100644
--- a/include/sound/pcm.h
+++ b/include/sound/pcm.h
@@ -348,6 +348,8 @@
int count;
};
+struct pid;
+
struct snd_pcm_substream {
struct snd_pcm *pcm;
struct snd_pcm_str *pstr;
@@ -379,6 +381,7 @@
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;