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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: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Alex Tran <alex.t.tran@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
This commit is contained in:
Alex Tran 2025-10-01 22:57:27 -07:00 committed by Bartosz Golaszewski
parent 383760e3fa
commit 411b39bd1a
1 changed files with 8 additions and 16 deletions
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22
drivers/gpio/gpio-grgpio.c
View File

@ -46,7 +46,7 @@
/* Structure for an irq of the core - called an underlying irq */ /* Structure for an irq of the core - called an underlying irq */
struct grgpio_uirq { 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 */ 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); irq, offset);
gpio_generic_chip_lock_irqsave(&priv->chip, flags); gpio_generic_chip_lock_irqsave(&priv->chip, flags);
/* Request underlying irq if not already requested */
lirq->irq = irq; lirq->irq = irq;
uirq = &priv->uirqs[lirq->index]; 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); 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, ret = request_irq(uirq->uirq, grgpio_irq_handler, 0,
dev_name(priv->dev), priv); dev_name(priv->dev), priv);
if (ret) { if (ret) {
dev_err(priv->dev, dev_err(priv->dev,
"Could not request underlying irq %d\n", "Could not request underlying irq %d\n",
uirq->uirq); uirq->uirq);
atomic_dec(&uirq->refcnt); /* rollback */
return ret; return ret;
} }
gpio_generic_chip_lock_irqsave(&priv->chip, flags);
} }
uirq->refcnt++;
gpio_generic_chip_unlock_irqrestore(&priv->chip, flags);
/* Setup irq */ /* Setup irq */
irq_set_chip_data(irq, priv); 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) { if (index >= 0) {
uirq = &priv->uirqs[lirq->index]; uirq = &priv->uirqs[lirq->index];
uirq->refcnt--; if (atomic_dec_and_test(&uirq->refcnt)) {
if (uirq->refcnt == 0) {
gpio_generic_chip_unlock_irqrestore(&priv->chip, flags); gpio_generic_chip_unlock_irqrestore(&priv->chip, flags);
free_irq(uirq->uirq, priv); free_irq(uirq->uirq, priv);
return; return;
@ -434,6 +425,7 @@ static int grgpio_probe(struct platform_device *ofdev)
continue; continue;
} }
priv->uirqs[lirq->index].uirq = ret; priv->uirqs[lirq->index].uirq = ret;
atomic_set(&priv->uirqs[lirq->index].refcnt, 0);
} }
} }