| Message ID | 1464095903-29145-1-git-send-email-ldewangan@nvidia.com |
|---|---|
| State | New |
| Headers | show |
On Tue, May 24, 2016 at 3:18 PM, Laxman Dewangan <ldewangan@nvidia.com> wrote: > When adding the gpiochip, the GPIO HW drivers' callback get_direction() > get called in atomic context. Some of the GPIO HW drivers can sleep when > accessing the register and hence it can create the sleeping call in > atomic context. > > Call get_direction() in non-atomic context from gpiochip_add() if GPIO > HW driver is having sleepable callback i.e. chip->can_sleep = 1. > > Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com> > > --- > This is found when implementing the get_direction() of max77620 on 20160520 > linux-next. I chose to send a new patch just moving the lock release before the direction check. I just sent it with you as Reported-by. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index d407f904..4d04171 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -636,7 +636,15 @@ int gpiochip_add_data(struct gpio_chip *chip, void *data) * If we have .get_direction, set up the initial * direction flag from the hardware. */ - int dir = chip->get_direction(chip, i); + int dir; + + if (chip->can_sleep) + spin_unlock_irqrestore(&gpio_lock, flags); + + dir = chip->get_direction(chip, i); + + if (chip->can_sleep) + spin_lock_irqsave(&gpio_lock, flags); if (!dir) set_bit(FLAG_IS_OUT, &desc->flags);
When adding the gpiochip, the GPIO HW drivers' callback get_direction() get called in atomic context. Some of the GPIO HW drivers can sleep when accessing the register and hence it can create the sleeping call in atomic context. Call get_direction() in non-atomic context from gpiochip_add() if GPIO HW driver is having sleepable callback i.e. chip->can_sleep = 1. Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com> --- This is found when implementing the get_direction() of max77620 on 20160520 linux-next. drivers/gpio/gpiolib.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)