linux-kernel - [PATCH 3.16 088/294] gpio: tegra: fix unbalanced chained_irq

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Message-ID: <lsq.1510009382.829587778@decadent.org.uk>
Date:   Mon, 06 Nov 2017 23:03:02 +0000
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org,
        "Michał Mirosław" <mirq-linux@...e.qmqm.pl>,
        "Linus Walleij" <linus.walleij@...aro.org>
Subject: [PATCH 3.16 088/294] gpio: tegra: fix unbalanced chained_irq_enter/exit

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

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

From: Michał Mirosław <mirq-linux@...e.qmqm.pl>

commit 9e9509e38fbe034782339eb09c915f0b5765ff69 upstream.

When more than one GPIO IRQs are triggered simultaneously,
tegra_gpio_irq_handler() called chained_irq_exit() multiple
times for one chained_irq_enter().

Fixes: 3c92db9ac0ca3eee8e46e2424b6c074e2e394ad9
Signed-off-by: Michał Mirosław <mirq-linux@...e.qmqm.pl>
[Also changed the variable to a bool]
Signed-off-by: Linus Walleij <linus.walleij@...aro.org>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/gpio/gpio-tegra.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/gpio/gpio-tegra.c
+++ b/drivers/gpio/gpio-tegra.c
@@ -271,7 +271,7 @@ static void tegra_gpio_irq_handler(unsig
 	struct tegra_gpio_bank *bank;
 	int port;
 	int pin;
-	int unmasked = 0;
+	bool unmasked = false;
 	struct irq_chip *chip = irq_desc_get_chip(desc);
 
 	chained_irq_enter(chip, desc);
@@ -291,8 +291,8 @@ static void tegra_gpio_irq_handler(unsig
 			 * before executing the hander so that we don't
 			 * miss edges
 			 */
-			if (lvl & (0x100 << pin)) {
-				unmasked = 1;
+			if (!unmasked && lvl & (0x100 << pin)) {
+				unmasked = true;
 				chained_irq_exit(chip, desc);
 			}