linux-kernel - [PATCH AUTOSEL 4.19 04/13] ASoC: rt5668: do not block workqueue if card is unbound

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Message-Id: <20220223023152.242065-4-sashal@kernel.org>
Date:   Tue, 22 Feb 2022 21:31:43 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Kai Vehmanen <kai.vehmanen@...ux.intel.com>,
        Bard Liao <yung-chuan.liao@...ux.intel.com>,
        Ranjani Sridharan <ranjani.sridharan@...ux.intel.com>,
        Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>,
        Péter Ujfalusi <peter.ujfalusi@...ux.intel.com>,
        Shuming Fan <shumingf@...ltek.com>,
        Mark Brown <broonie@...nel.org>,
        Sasha Levin <sashal@...nel.org>, oder_chiou@...ltek.com,
        lgirdwood@...il.com, perex@...ex.cz, tiwai@...e.com,
        alsa-devel@...a-project.org
Subject: [PATCH AUTOSEL 4.19 04/13] ASoC: rt5668: do not block workqueue if card is unbound

From: Kai Vehmanen <kai.vehmanen@...ux.intel.com>

[ 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@...ux.intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@...ux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@...ux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@...ux.intel.com>
Reviewed-by: Shuming Fan <shumingf@...ltek.com>
Link: https://lore.kernel.org/r/20220207153000.3452802-2-kai.vehmanen@linux.intel.com
Signed-off-by: Mark Brown <broonie@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 sound/soc/codecs/rt5668.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/sound/soc/codecs/rt5668.c b/sound/soc/codecs/rt5668.c
index 3c19d03f2446b..a78503f24aa8a 100644
--- a/sound/soc/codecs/rt5668.c
+++ b/sound/soc/codecs/rt5668.c
@@ -1025,11 +1025,13 @@ 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);
 
-- 
2.34.1