diff mbox series

[v2,2/3] irqdomain: Fix irq_domain_trim_hierarchy()

Message ID 1629373993-13370-3-git-send-email-mkshah@codeaurora.org
State New
Headers show
Series Start getting rid of the GPIO_NO_WAKE_IRQ | expand

Commit Message

Maulik Shah Aug. 19, 2021, 11:53 a.m. UTC
Currently tail marker is moving along with parent domain
irq data. Fix this to initialize only once from where all
parent domain needs trimming.

Also correct the valid irq chip check.

Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
---
 kernel/irq/irqdomain.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Comments

Marc Zyngier Aug. 20, 2021, 3:54 p.m. UTC | #1
On Thu, 19 Aug 2021 12:53:12 +0100,
Maulik Shah <mkshah@codeaurora.org> wrote:
> 
> Currently tail marker is moving along with parent domain
> irq data. Fix this to initialize only once from where all
> parent domain needs trimming.
> 
> Also correct the valid irq chip check.
> 
> Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
> ---
>  kernel/irq/irqdomain.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
> index 19e83e9..9f6187b 100644
> --- a/kernel/irq/irqdomain.c
> +++ b/kernel/irq/irqdomain.c
> @@ -1235,7 +1235,7 @@ static int irq_domain_trim_hierarchy(unsigned int virq)
>  	 */
>  	for (irqd = irq_data->parent_data; irqd; irq_data = irqd, irqd = irqd->parent_data) {
>  		/* Can't have a valid irqchip after a trim marker */
> -		if (irqd->chip && tail)
> +		if (!IS_ERR(irqd->chip) && tail)
>  			return -EINVAL;
>  
>  		/* Can't have an empty irqchip before a trim marker */
> @@ -1247,7 +1247,8 @@ static int irq_domain_trim_hierarchy(unsigned int virq)
>  			if (PTR_ERR(irqd->chip) != -ENOTCONN)
>  				return -EINVAL;
>  
> -			tail = irq_data;
> +			if (!tail)
> +				tail = irq_data;
>  		}
>  	}

I think you have the wrong end of the stick. 'tail' represent the
*unique* point in the hierarchy where you can have a trim marker:

(1) If there is a valid irqchip after a trim marker, this is wrong
(2) If there is a trim marker after another trim marker, this is wrong
(3) If there is a NULL irqchip before a trim marker, this is wrong
(4) If there is an error that isn't a trim marker, this is wrong

(1) and (2) are captured by:
		if (irqd->chip && tail)
(3) is captured by:
		if (!irqd->chip && !tail)
(4) is captured by:
		if (IS_ERR(irqd->chip)) {
			/* Only -ENOTCONN is a valid trim marker */
			if (PTR_ERR(irqd->chip) != -ENOTCONN)

The expected usage is that:

- there is a single potential trim marker in the hierarchy
- all the irqd->chip pointers below the marker are NULL
- all the irqd->chip before the marker are neither NULL nor an error

I don't see any bug here.

Thanks,

	M.
diff mbox series

Patch

diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index 19e83e9..9f6187b 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -1235,7 +1235,7 @@  static int irq_domain_trim_hierarchy(unsigned int virq)
 	 */
 	for (irqd = irq_data->parent_data; irqd; irq_data = irqd, irqd = irqd->parent_data) {
 		/* Can't have a valid irqchip after a trim marker */
-		if (irqd->chip && tail)
+		if (!IS_ERR(irqd->chip) && tail)
 			return -EINVAL;
 
 		/* Can't have an empty irqchip before a trim marker */
@@ -1247,7 +1247,8 @@  static int irq_domain_trim_hierarchy(unsigned int virq)
 			if (PTR_ERR(irqd->chip) != -ENOTCONN)
 				return -EINVAL;
 
-			tail = irq_data;
+			if (!tail)
+				tail = irq_data;
 		}
 	}