Patch "ASoC: rt5668: do not block workqueue if card is unbound" has been added to the 5.16-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    ASoC: rt5668: do not block workqueue if card is unbound

to the 5.16-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     asoc-rt5668-do-not-block-workqueue-if-card-is-unboun.patch
and it can be found in the queue-5.16 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 15d87134d40773f482b2d6c198b832d189b92ed7
Author: Kai Vehmanen <kai.vehmanen@xxxxxxxxxxxxxxx>
Date:   Mon Feb 7 17:29:59 2022 +0200

    ASoC: rt5668: do not block workqueue if card is unbound
    
    [ Upstream commit a6d78661dc903d90a327892bbc34268f3a5f4b9c ]
    
    The current rt5668_jack_detect_handler() assumes the component
    and card will always show up and implements an infinite usleep
    loop waiting for them to show up.
    
    This does not hold true if a codec interrupt (or other
    event) occurs when the card is unbound. The codec driver's
    remove  or shutdown functions cannot cancel the workqueue due
    to the wait loop. As a result, code can either end up blocking
    the workqueue, or hit a kernel oops when the card is freed.
    
    Fix the issue by rescheduling the jack detect handler in
    case the card is not ready. In case card never shows up,
    the shutdown/remove/suspend calls can now cancel the detect
    task.
    
    Signed-off-by: Kai Vehmanen <kai.vehmanen@xxxxxxxxxxxxxxx>
    Reviewed-by: Bard Liao <yung-chuan.liao@xxxxxxxxxxxxxxx>
    Reviewed-by: Ranjani Sridharan <ranjani.sridharan@xxxxxxxxxxxxxxx>
    Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
    Reviewed-by: Péter Ujfalusi <peter.ujfalusi@xxxxxxxxxxxxxxx>
    Reviewed-by: Shuming Fan <shumingf@xxxxxxxxxxx>
    Link: https://lore.kernel.org/r/20220207153000.3452802-2-kai.vehmanen@xxxxxxxxxxxxxxx
    Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/sound/soc/codecs/rt5668.c b/sound/soc/codecs/rt5668.c
index fb09715bf9328..5b12cbf2ba215 100644
--- a/sound/soc/codecs/rt5668.c
+++ b/sound/soc/codecs/rt5668.c
@@ -1022,11 +1022,13 @@ static void rt5668_jack_detect_handler(struct work_struct *work)
 		container_of(work, struct rt5668_priv, jack_detect_work.work);
 	int val, btn_type;
 
-	while (!rt5668->component)
-		usleep_range(10000, 15000);
-
-	while (!rt5668->component->card->instantiated)
-		usleep_range(10000, 15000);
+	if (!rt5668->component || !rt5668->component->card ||
+	    !rt5668->component->card->instantiated) {
+		/* card not yet ready, try later */
+		mod_delayed_work(system_power_efficient_wq,
+				 &rt5668->jack_detect_work, msecs_to_jiffies(15));
+		return;
+	}
 
 	mutex_lock(&rt5668->calibrate_mutex);