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| author | Takashi Iwai <tiwai@suse.de> | 2022-07-28 14:59:45 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2022-07-29 12:57:12 +0200 |
| commit | 4a971e84a7ae10a38d875cd2d4e487c8d1682ca3 (patch) | |
| tree | 750576e84d71b0f772fdb1c267e340ede1377de4 /sound/core | |
| parent | ALSA: pcm: Use deferred fasync helper (diff) | |
| download | linux-4a971e84a7ae10a38d875cd2d4e487c8d1682ca3.tar.xz linux-4a971e84a7ae10a38d875cd2d4e487c8d1682ca3.zip | |
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.c | 7 |
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); |