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control: use reference-counted pid

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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>
This commit is contained in:
Clemens Ladisch
2009-11-02 09:35:44 +01:00
committed by Takashi Iwai
parent 31cef7076e
commit 25d27eded1
4 changed files with 8 additions and 5 deletions
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5
sound/core/control.c
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@@ -75,7 +75,7 @@ static int snd_ctl_open(struct inode *inode, struct file *file)
ctl->card = card;
ctl->prefer_pcm_subdevice = -1;
ctl->prefer_rawmidi_subdevice = -1;
ctl->pid = current->pid;
ctl->pid = get_pid(task_pid(current));
file->private_data = ctl;
write_lock_irqsave(&card->ctl_files_rwlock, flags);
list_add_tail(&ctl->list, &card->ctl_files);
@@ -125,6 +125,7 @@ static int snd_ctl_release(struct inode *inode, struct file *file)
control->vd[idx].owner = NULL;
up_write(&card->controls_rwsem);
snd_ctl_empty_read_queue(ctl);
put_pid(ctl->pid);
kfree(ctl);
module_put(card->module);
snd_card_file_remove(card, file);
@@ -672,7 +673,7 @@ static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
if (vd->owner == ctl)
info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
info->owner = vd->owner->pid;
info->owner = pid_vnr(vd->owner->pid);
} else {
info->owner = -1;
}