Re: [PATCH 2/2] irqchip/armada-370-xp: Fix support for Multi-MSI interrupts

[Marc Zyngier <maz@kernel.org>]

On Thu, 25 Nov 2021 13:00:57 +0000,
Pali Rohár <pali@kernel.org> wrote:
> 
> irq-armada-370-xp driver already sets MSI_FLAG_MULTI_PCI_MSI flag into
> msi_domain_info structure. But allocated interrupt numbers for Multi-MSI
> needs to be properly aligned otherwise devices send MSI interrupt with
> wrong number.
> 
> Fix this issue by using function bitmap_find_free_region() instead of
> bitmap_find_next_zero_area() to allocate aligned interrupt numbers.
> 
> Signed-off-by: Pali Rohár <pali@kernel.org>
> Fixes: a71b9412c90c ("irqchip/armada-370-xp: Allow allocation of multiple MSIs")
> Cc: stable@vger.kernel.org
> ---
>  drivers/irqchip/irq-armada-370-xp.c | 14 +++++---------
>  1 file changed, 5 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/irqchip/irq-armada-370-xp.c b/drivers/irqchip/irq-armada-370-xp.c
> index 41ad745cf343..5b8d571c041d 100644
> --- a/drivers/irqchip/irq-armada-370-xp.c
> +++ b/drivers/irqchip/irq-armada-370-xp.c
> @@ -232,16 +232,12 @@ static int armada_370_xp_msi_alloc(struct irq_domain *domain, unsigned int virq,
>  	int hwirq, i;
>  
>  	mutex_lock(&msi_used_lock);
> +	hwirq = bitmap_find_free_region(msi_used, PCI_MSI_DOORBELL_NR,
> +					order_base_2(nr_irqs));
> +	mutex_unlock(&msi_used_lock);
>  
> -	hwirq = bitmap_find_next_zero_area(msi_used, PCI_MSI_DOORBELL_NR,
> -					   0, nr_irqs, 0);
> -	if (hwirq >= PCI_MSI_DOORBELL_NR) {
> -		mutex_unlock(&msi_used_lock);
> +	if (hwirq < 0)
>  		return -ENOSPC;
> -	}
> -
> -	bitmap_set(msi_used, hwirq, nr_irqs);
> -	mutex_unlock(&msi_used_lock);
>  
>  	for (i = 0; i < nr_irqs; i++) {
>  		irq_domain_set_info(domain, virq + i, hwirq + i,
> @@ -259,7 +255,7 @@ static void armada_370_xp_msi_free(struct irq_domain *domain,
>  	struct irq_data *d = irq_domain_get_irq_data(domain, virq);
>  
>  	mutex_lock(&msi_used_lock);
> -	bitmap_clear(msi_used, d->hwirq, nr_irqs);
> +	bitmap_release_region(msi_used, d->hwirq, order_base_2(nr_irqs));
>  	mutex_unlock(&msi_used_lock);
>  }
>  
> -- 
> 2.20.1
> 
> 

Acked-by: Marc Zyngier <maz@kernel.org>

	M.

-- 
Without deviation from the norm, progress is not possible.

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