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authorTakashi Iwai <tiwai@suse.de>2022-07-28 15:59:45 +0300
committerTakashi Iwai <tiwai@suse.de>2022-07-29 13:57:12 +0300
commit4a971e84a7ae10a38d875cd2d4e487c8d1682ca3 (patch)
tree750576e84d71b0f772fdb1c267e340ede1377de4 /sound/core
parent96b097091c66df4f6fbf5cbff21df6cc02a2f055 (diff)
downloadlinux-4a971e84a7ae10a38d875cd2d4e487c8d1682ca3.tar.xz
ALSA: control: Use deferred fasync helper
For avoiding the potential deadlock via kill_fasync() call, use the new fasync helpers to defer the invocation from the control API. Note that it's merely a workaround. Another note: although we haven't received reports about the deadlock with the control API, the deadlock is still potentially possible, and it's better to align the behavior with other core APIs (PCM and timer); so let's move altogether. Link: https://lore.kernel.org/r/20220728125945.29533-5-tiwai@suse.de Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/core')
-rw-r--r--sound/core/control.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/sound/core/control.c b/sound/core/control.c
index 4dba3a342458..f3e893715369 100644
--- a/sound/core/control.c
+++ b/sound/core/control.c
@@ -127,6 +127,7 @@ static int snd_ctl_release(struct inode *inode, struct file *file)
if (control->vd[idx].owner == ctl)
control->vd[idx].owner = NULL;
up_write(&card->controls_rwsem);
+ snd_fasync_free(ctl->fasync);
snd_ctl_empty_read_queue(ctl);
put_pid(ctl->pid);
kfree(ctl);
@@ -181,7 +182,7 @@ void snd_ctl_notify(struct snd_card *card, unsigned int mask,
_found:
wake_up(&ctl->change_sleep);
spin_unlock(&ctl->read_lock);
- kill_fasync(&ctl->fasync, SIGIO, POLL_IN);
+ snd_kill_fasync(ctl->fasync, SIGIO, POLL_IN);
}
read_unlock_irqrestore(&card->ctl_files_rwlock, flags);
}
@@ -2134,7 +2135,7 @@ static int snd_ctl_fasync(int fd, struct file * file, int on)
struct snd_ctl_file *ctl;
ctl = file->private_data;
- return fasync_helper(fd, file, on, &ctl->fasync);
+ return snd_fasync_helper(fd, file, on, &ctl->fasync);
}
/* return the preferred subdevice number if already assigned;
@@ -2302,7 +2303,7 @@ static int snd_ctl_dev_disconnect(struct snd_device *device)
read_lock_irqsave(&card->ctl_files_rwlock, flags);
list_for_each_entry(ctl, &card->ctl_files, list) {
wake_up(&ctl->change_sleep);
- kill_fasync(&ctl->fasync, SIGIO, POLL_ERR);
+ snd_kill_fasync(ctl->fasync, SIGIO, POLL_ERR);
}
read_unlock_irqrestore(&card->ctl_files_rwlock, flags);