Re: [virtio_pci?] WARNING: possible circular locking dependency detected

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] virtio: missing indentation for if-statement body in vp_setup_vq()
--

commit 109e547b3fda2539201c9831108e08b3f9d3dbe9
Author: Zenghui Yu <zenghui.yu@linux.dev>

WARNING: possible circular locking dependency detected

This commit addresses a circular locking dependency involving cpu_hotplug_lock,
the MSI mutex, and the IOMMU group mutex in virtio_pci. It caches the Linux IRQ
number in virtio_pci_vq_info to avoid calling pci_irq_vector() and taking the
MSI mutex under the cpu_hotplug_lock.

> diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
> index b90c174450b20..df2774fb6d845 100644
> --- a/drivers/virtio/virtio_pci_common.c
> +++ b/drivers/virtio/virtio_pci_common.c

[ ... ]

> @@ -224,6 +224,16 @@ static struct virtqueue *vp_setup_vq(struct virtio_device *vdev, unsigned int in
>  		goto out_info;
>  
>  	info->vq = vq;
> +
> +	/*
> +	 * Cache the Linux IRQ number so that later users (e.g.
> +	 * vp_set_vq_affinity() from cpu hotplug locked contexts)
> +	 * don't have to take the MSI mutex via pci_irq_vector().
> +	 */
> +	info->virq = 0;
> +	if (msix_vec != VIRTIO_MSI_NO_VECTOR)
> +	info->virq = pci_irq_vector(vp_dev->pci_dev, msix_vec);

[Severity: Low]
This isn't a bug, but is the body of this if-statement in vp_setup_vq()
missing a tab of indentation?

> +
>  	if (callback) {
>  		spin_lock_irqsave(&vp_dev->lock, flags);
>  		if (!vp_is_slow_path_vector(msix_vec))

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/98f2f4f9-a7fe-413e-a366-7bed08290697@linux.dev?part=1