Commit 411b39bd authored by Alex Tran's avatar Alex Tran Committed by Bartosz Golaszewski
Browse files

gpio: grgpio: call request_irq after incrementing the reference count 



Remove extraneous dropping of the lock just to call 'request_irq'
and locking again afterwards. Increment reference count
before calling 'request_irq'. Rollback reference count if
'request_irq' fails.

Suggested-by: default avatarBartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: default avatarAlex Tran <alex.t.tran@gmail.com>
Signed-off-by: default avatarBartosz Golaszewski <bartosz.golaszewski@linaro.org>
parent 383760e3

drivers/gpio/gpio-grgpio.c

+8 −16
Original line number Diff line number Diff line
@@ -46,7 +46,7 @@ 


/* Structure for an irq of the core - called an underlying irq */

struct grgpio_uirq {

	u8 refcnt; /* Reference counter to manage requesting/freeing of uirq */

	atomic_t refcnt; /* Reference counter to manage requesting/freeing of uirq */

	u8 uirq; /* Underlying irq of the gpio driver */

};
@@ -242,30 +242,22 @@ static int grgpio_irq_map(struct irq_domain *d, unsigned int irq, 
		irq, offset);



	gpio_generic_chip_lock_irqsave(&priv->chip, flags);



	/* Request underlying irq if not already requested */

	lirq->irq = irq;

	uirq = &priv->uirqs[lirq->index];

	if (uirq->refcnt == 0) {

		/*

		 * FIXME: This is not how locking works at all, you can't just

		 * release the lock for a moment to do something that can't

		 * sleep...

		 */

	gpio_generic_chip_unlock_irqrestore(&priv->chip, flags);



	/* Request underlying irq if not already requested */

	if (atomic_fetch_add(1, &uirq->refcnt) == 0) {

		ret = request_irq(uirq->uirq, grgpio_irq_handler, 0,

				  dev_name(priv->dev), priv);

		if (ret) {

			dev_err(priv->dev,

				"Could not request underlying irq %d\n",

				uirq->uirq);

			atomic_dec(&uirq->refcnt); /* rollback */

			return ret;

		}

		gpio_generic_chip_lock_irqsave(&priv->chip, flags);

	}

	uirq->refcnt++;



	gpio_generic_chip_unlock_irqrestore(&priv->chip, flags);



	/* Setup irq  */

	irq_set_chip_data(irq, priv);
@@ -306,8 +298,7 @@ static void grgpio_irq_unmap(struct irq_domain *d, unsigned int irq) 


	if (index >= 0) {

		uirq = &priv->uirqs[lirq->index];

		uirq->refcnt--;

		if (uirq->refcnt == 0) {

		if (atomic_dec_and_test(&uirq->refcnt)) {

			gpio_generic_chip_unlock_irqrestore(&priv->chip, flags);

			free_irq(uirq->uirq, priv);

			return;
@@ -434,6 +425,7 @@ static int grgpio_probe(struct platform_device *ofdev) 
				continue;

			}

			priv->uirqs[lirq->index].uirq = ret;

			atomic_set(&priv->uirqs[lirq->index].refcnt, 0);

		}

	}