control: use reference-counted pid

Instead of storing the PID number, take a reference to the task's pid
structure.  This protects against duplicates due to PID overflows, and
using pid_vnr() ensures that the PID returned by snd_ctl_elem_info() is
correct as seen from the current namespace.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 1 insertions, 1 deletions

diff --git a/sound/core/pcm.c b/sound/core/pcm.c
index c69c60b2a48a..8e2c7833614c 100644
--- a/sound/core/pcm.c
+++ b/sound/core/pcm.c
@@ -809,7 +809,7 @@ int snd_pcm_attach_substream(struct snd_pcm *pcm, int stream,
         card = pcm->card;
         read_lock(&card->ctl_files_rwlock);
         list_for_each_entry(kctl, &card->ctl_files, list) {
-                if (kctl->pid == current->pid) {
+                if (kctl->pid == task_pid(current)) {
                         prefer_subdevice = kctl->prefer_pcm_subdevice;
                         if (prefer_subdevice != -1)
                                 break;