[PATCH 3.16 141/245] ALSA: ice1724: Fix sleep-in-atomic in Infrasonic Quartet support code

[Ben Hutchings]

3.16.83-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Takashi Iwai <tiwai@xxxxxxx>

commit 0aec96f5897ac16ad9945f531b4bef9a2edd2ebd upstream.

Jia-Ju Bai reported a possible sleep-in-atomic scenario in the ice1724
driver with Infrasonic Quartet support code: namely, ice->set_rate
callback gets called inside ice->reg_lock spinlock, while the callback
in quartet.c holds ice->gpio_mutex.

This patch fixes the invalid call: it simply moves the calls of
ice->set_rate and ice->set_mclk callbacks outside the spinlock.

Reported-by: Jia-Ju Bai <baijiaju1990@xxxxxxxxx>
Link: https://lore.kernel.org/r/5d43135e-73b9-a46a-2155-9e91d0dcdf83@xxxxxxxxx
Link: https://lore.kernel.org/r/20191218192606.12866-1-tiwai@xxxxxxx
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 sound/pci/ice1712/ice1724.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

--- a/sound/pci/ice1712/ice1724.c
+++ b/sound/pci/ice1712/ice1724.c
@@ -663,6 +663,7 @@ static int snd_vt1724_set_pro_rate(struc
 	unsigned long flags;
 	unsigned char mclk_change;
 	unsigned int i, old_rate;
+	bool call_set_rate = false;
 
 	if (rate > ice->hw_rates->list[ice->hw_rates->count - 1])
 		return -EINVAL;
@@ -686,7 +687,7 @@ static int snd_vt1724_set_pro_rate(struc
 		 * setting clock rate for internal clock mode */
 		old_rate = ice->get_rate(ice);
 		if (force || (old_rate != rate))
-			ice->set_rate(ice, rate);
+			call_set_rate = true;
 		else if (rate == ice->cur_rate) {
 			spin_unlock_irqrestore(&ice->reg_lock, flags);
 			return 0;
@@ -694,12 +695,14 @@ static int snd_vt1724_set_pro_rate(struc
 	}
 
 	ice->cur_rate = rate;
+	spin_unlock_irqrestore(&ice->reg_lock, flags);
+
+	if (call_set_rate)
+		ice->set_rate(ice, rate);
 
 	/* setting master clock */
 	mclk_change = ice->set_mclk(ice, rate);
 
-	spin_unlock_irqrestore(&ice->reg_lock, flags);
-
 	if (mclk_change && ice->gpio.i2s_mclk_changed)
 		ice->gpio.i2s_mclk_changed(ice);
 	if (ice->gpio.set_pro_rate)