linux-kernel - [PATCH 4.9 126/206] ASoC: samsung: i2s: Fixup last IRQ unsafe spin lock call

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Date:   Tue, 10 Jan 2017 14:36:49 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Sylwester Nawrocki <s.nawrocki@...sung.com>,
        Mark Brown <broonie@...nel.org>
Subject: [PATCH 4.9 126/206] ASoC: samsung: i2s: Fixup last IRQ unsafe spin lock call

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>

commit 5faf071d08ddd1c1be66deaa93a09ccf43f5b538 upstream.

Unfortunately, I seem to have missed a case where an IRQ safe spinlock was
required, in samsung_i2s_dai_remove, when I fixed up the other calls in
this patch:

316fa9e09ad7 ("ASoC: samsung: Use IRQ safe spin lock calls")

This causes a lockdep warning when unbinding and rebinding the audio card:

[  104.357664]        CPU0                    CPU1
[  104.362174]        ----                    ----
[  104.366692]   lock(&(&pri_dai->spinlock)->rlock);
[  104.371372]                                local_irq_disable();
[  104.377283]                                lock(&(&substream->self_group.lock)->rlock);
[  104.385259]                                lock(&(&pri_dai->spinlock)->rlock);
[  104.392469]   <Interrupt>
[  104.395072]     lock(&(&substream->self_group.lock)->rlock);
[  104.400710]
[  104.400710]  *** DEADLOCK ***

Fixes: ce8bcdbb61d9 ("ASoC: samsung: i2s: Protect more registers with a spinlock")
Signed-off-by: Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>
Reviewed-by: Krzysztof Kozlowski <krzk@...nel.org>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@...sung.com>
Signed-off-by: Mark Brown <broonie@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 sound/soc/samsung/i2s.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/sound/soc/samsung/i2s.c
+++ b/sound/soc/samsung/i2s.c
@@ -1029,12 +1029,13 @@ static int samsung_i2s_dai_probe(struct
 static int samsung_i2s_dai_remove(struct snd_soc_dai *dai)
 {
 	struct i2s_dai *i2s = snd_soc_dai_get_drvdata(dai);
+	unsigned long flags;
 
 	if (!is_secondary(i2s)) {
 		if (i2s->quirks & QUIRK_NEED_RSTCLR) {
-			spin_lock(i2s->lock);
+			spin_lock_irqsave(i2s->lock, flags);
 			writel(0, i2s->addr + I2SCON);
-			spin_unlock(i2s->lock);
+			spin_unlock_irqrestore(i2s->lock, flags);
 		}
 	}