linux-kernel - [PATCH] drivers: gpio: gpio-adp5588: Fix sleep-in-atomic-context bug

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Message-ID: <1534168664-13034-1-git-send-email-michael.hennerich@analog.com>
Date:   Mon, 13 Aug 2018 15:57:44 +0200
From:   <michael.hennerich@...log.com>
To:     <linus.walleij@...aro.org>
CC:     <linux-gpio@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <baijiaju1990@...il.com>,
        Michael Hennerich <michael.hennerich@...log.com>
Subject: [PATCH] drivers: gpio: gpio-adp5588: Fix sleep-in-atomic-context bug

From: Michael Hennerich <michael.hennerich@...log.com>

This fixes:
[BUG] gpio: gpio-adp5588: A possible sleep-in-atomic-context bug
                          in adp5588_gpio_write()
[BUG] gpio: gpio-adp5588: A possible sleep-in-atomic-context bug
                          in adp5588_gpio_direction_input()

Reported-by: Jia-Ju Bai <baijiaju1990@...il.com>
Signed-off-by: Michael Hennerich <michael.hennerich@...log.com>
---
 drivers/gpio/gpio-adp5588.c | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/drivers/gpio/gpio-adp5588.c b/drivers/gpio/gpio-adp5588.c
index e717f8d..202d367 100644
--- a/drivers/gpio/gpio-adp5588.c
+++ b/drivers/gpio/gpio-adp5588.c
@@ -41,6 +41,8 @@ struct adp5588_gpio {
 	uint8_t int_en[3];
 	uint8_t irq_mask[3];
 	uint8_t irq_stat[3];
+	uint8_t int_input_en[3];
+	uint8_t int_lvl_cached[3];
 };
 
 static int adp5588_gpio_read(struct i2c_client *client, u8 reg)
@@ -173,12 +175,28 @@ static void adp5588_irq_bus_sync_unlock(struct irq_data *d)
 	struct adp5588_gpio *dev = irq_data_get_irq_chip_data(d);
 	int i;
 
-	for (i = 0; i <= ADP5588_BANK(ADP5588_MAXGPIO); i++)
+	for (i = 0; i <= ADP5588_BANK(ADP5588_MAXGPIO); i++) {
+		if (dev->int_input_en[i]) {
+			mutex_lock(&dev->lock);
+			dev->dir[i] &= ~dev->int_input_en[i];
+			dev->int_input_en[i] = 0;
+			adp5588_gpio_write(dev->client, GPIO_DIR1 + i,
+					   dev->dir[i]);
+			mutex_unlock(&dev->lock);
+		}
+
+		if (dev->int_lvl_cached[i] != dev->int_lvl[i]) {
+			dev->int_lvl_cached[i] = dev->int_lvl[i];
+			adp5588_gpio_write(dev->client, GPIO_INT_LVL1 + i,
+					   dev->int_lvl[i]);
+		}
+
 		if (dev->int_en[i] ^ dev->irq_mask[i]) {
 			dev->int_en[i] = dev->irq_mask[i];
 			adp5588_gpio_write(dev->client, GPIO_INT_EN1 + i,
 					   dev->int_en[i]);
 		}
+	}
 
 	mutex_unlock(&dev->irq_lock);
 }
@@ -221,9 +239,7 @@ static int adp5588_irq_set_type(struct irq_data *d, unsigned int type)
 	else
 		return -EINVAL;
 
-	adp5588_gpio_direction_input(&dev->gpio_chip, gpio);
-	adp5588_gpio_write(dev->client, GPIO_INT_LVL1 + bank,
-			   dev->int_lvl[bank]);
+	dev->int_input_en[bank] |= bit;
 
 	return 0;
 }
-- 
2.7.4