linux-kernel - [PATCH 1/5] gpio: thunderx: avoid potential deadlock

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Date:   Wed, 27 Apr 2022 07:46:16 -0700
From:   Piyush Malgujar <pmalgujar@...vell.com>
To:     <linux-gpio@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <devicetree@...r.kernel.org>
CC:     <linus.walleij@...aro.org>, <brgl@...ev.pl>, <robh+dt@...nel.org>,
        <krzysztof.kozlowski+dt@...aro.org>, <rric@...nel.org>,
        <cchavva@...vell.com>, <wsadowski@...vell.com>,
        Piyush Malgujar <pmalgujar@...vell.com>
Subject: [PATCH 1/5] gpio: thunderx: avoid potential deadlock

Using irqsave/irqrestore locking variants to avoid any deadlock.

Signed-off-by: Piyush Malgujar <pmalgujar@...vell.com>
---
 drivers/gpio/gpio-thunderx.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/drivers/gpio/gpio-thunderx.c b/drivers/gpio/gpio-thunderx.c
index 9f66deab46eaa99d05413a996b585284c433574d..bb2b40e4033b00134af35592b6b7c7f83cf6c737 100644
--- a/drivers/gpio/gpio-thunderx.c
+++ b/drivers/gpio/gpio-thunderx.c
@@ -104,16 +104,17 @@ static int thunderx_gpio_request(struct gpio_chip *chip, unsigned int line)
 static int thunderx_gpio_dir_in(struct gpio_chip *chip, unsigned int line)
 {
 	struct thunderx_gpio *txgpio = gpiochip_get_data(chip);
+	unsigned long flags;
 
 	if (!thunderx_gpio_is_gpio(txgpio, line))
 		return -EIO;
 
-	raw_spin_lock(&txgpio->lock);
+	raw_spin_lock_irqsave(&txgpio->lock, flags);
 	clear_bit(line, txgpio->invert_mask);
 	clear_bit(line, txgpio->od_mask);
 	writeq(txgpio->line_entries[line].fil_bits,
 	       txgpio->register_base + bit_cfg_reg(line));
-	raw_spin_unlock(&txgpio->lock);
+	raw_spin_unlock_irqrestore(&txgpio->lock, flags);
 	return 0;
 }
 
@@ -135,11 +136,12 @@ static int thunderx_gpio_dir_out(struct gpio_chip *chip, unsigned int line,
 {
 	struct thunderx_gpio *txgpio = gpiochip_get_data(chip);
 	u64 bit_cfg = txgpio->line_entries[line].fil_bits | GPIO_BIT_CFG_TX_OE;
+	unsigned long flags;
 
 	if (!thunderx_gpio_is_gpio(txgpio, line))
 		return -EIO;
 
-	raw_spin_lock(&txgpio->lock);
+	raw_spin_lock_irqsave(&txgpio->lock, flags);
 
 	thunderx_gpio_set(chip, line, value);
 
@@ -151,7 +153,7 @@ static int thunderx_gpio_dir_out(struct gpio_chip *chip, unsigned int line,
 
 	writeq(bit_cfg, txgpio->register_base + bit_cfg_reg(line));
 
-	raw_spin_unlock(&txgpio->lock);
+	raw_spin_unlock_irqrestore(&txgpio->lock, flags);
 	return 0;
 }
 
@@ -188,11 +190,12 @@ static int thunderx_gpio_set_config(struct gpio_chip *chip,
 	int ret = -ENOTSUPP;
 	struct thunderx_gpio *txgpio = gpiochip_get_data(chip);
 	void __iomem *reg = txgpio->register_base + (bank * GPIO_2ND_BANK) + GPIO_TX_SET;
+	unsigned long flags;
 
 	if (!thunderx_gpio_is_gpio(txgpio, line))
 		return -EIO;
 
-	raw_spin_lock(&txgpio->lock);
+	raw_spin_lock_irqsave(&txgpio->lock, flags);
 	orig_invert = test_bit(line, txgpio->invert_mask);
 	new_invert  = orig_invert;
 	orig_od = test_bit(line, txgpio->od_mask);
@@ -243,7 +246,7 @@ static int thunderx_gpio_set_config(struct gpio_chip *chip,
 	default:
 		break;
 	}
-	raw_spin_unlock(&txgpio->lock);
+	raw_spin_unlock_irqrestore(&txgpio->lock, flags);
 
 	/*
 	 * If currently output and OPEN_DRAIN changed, install the new
@@ -329,6 +332,7 @@ static int thunderx_gpio_irq_set_type(struct irq_data *d,
 	struct thunderx_gpio *txgpio = gpiochip_get_data(gc);
 	struct thunderx_line *txline =
 		&txgpio->line_entries[irqd_to_hwirq(d)];
+	unsigned long flags;
 	u64 bit_cfg;
 
 	irqd_set_trigger_type(d, flow_type);
@@ -342,7 +346,7 @@ static int thunderx_gpio_irq_set_type(struct irq_data *d,
 		irq_set_handler_locked(d, handle_fasteoi_mask_irq);
 	}
 
-	raw_spin_lock(&txgpio->lock);
+	raw_spin_lock_irqsave(&txgpio->lock, flags);
 	if (flow_type & (IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_LEVEL_LOW)) {
 		bit_cfg |= GPIO_BIT_CFG_PIN_XOR;
 		set_bit(txline->line, txgpio->invert_mask);
@@ -351,7 +355,7 @@ static int thunderx_gpio_irq_set_type(struct irq_data *d,
 	}
 	clear_bit(txline->line, txgpio->od_mask);
 	writeq(bit_cfg, txgpio->register_base + bit_cfg_reg(txline->line));
-	raw_spin_unlock(&txgpio->lock);
+	raw_spin_unlock_irqrestore(&txgpio->lock, flags);
 
 	return IRQ_SET_MASK_OK;
 }
-- 
2.17.1