linux-kernel - [PATCH] gpiolib: fix filtering out unwanted events

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Date:   Fri, 23 Jun 2017 13:45:16 +0200
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Linus Walleij <linus.walleij@...aro.org>
Cc:     linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
        Bartosz Golaszewski <brgl@...ev.pl>
Subject: [PATCH] gpiolib: fix filtering out unwanted events

GPIOEVENT_REQUEST_BOTH_EDGES is not a single flag, but a binary OR of
GPIOEVENT_REQUEST_RISING_EDGE and GPIOEVENT_REQUEST_FALLING_EDGE.

The expression 'le->eflags & GPIOEVENT_REQUEST_BOTH_EDGES' we'll get
evaluated to true even if only one event type was requested.

Fix it by checking both RISING & FALLING flags explicitly.

Signed-off-by: Bartosz Golaszewski <brgl@...ev.pl>
---
 drivers/gpio/gpiolib.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 5db4413..a42a1ee 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -708,7 +708,8 @@ static irqreturn_t lineevent_irq_thread(int irq, void *p)
 
 	ge.timestamp = ktime_get_real_ns();
 
-	if (le->eflags & GPIOEVENT_REQUEST_BOTH_EDGES) {
+	if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE
+	    && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
 		int level = gpiod_get_value_cansleep(le->desc);
 
 		if (level)
-- 
2.9.3