Re: [PATCH net-next v3 2/3] net: stmmac: Add glue driver for Motorcomm YT6801 ethernet controller

Russell King (Oracle)
2025-12-08T10:16:35Z

On Mon, Dec 08, 2025 at 10:54:36AM +0100, Philipp Stanner wrote:
> The bad news is that it's not super trivial to remove. I looked into it
> about two times and decided I can't invest that time currently. You
> need to go over all drivers again to see who uses pcim_enable_device(),
> then add free_irq_vecs() for them all and so on…

So that I can confirm, you're saying that all drivers that call
pci_alloc_irq_vectors() should call pci_free_irq_vectors() in their
->remove() method and not rely on the devres behaviour that
pcim_enable_device() will permit.

In terms of whether it's safe to call this twice, pci_free_irq_vectors()
calls pci_disable_msix() and pci_disable_msi().

pci_disable_msix() checks:

if (!pci_msi_enabled() || !dev || !dev->msix_enabled)
return;

which will set dev->msix_enabled to 0 via pci_msix_shutdown().

pci_disable_msi() does a similar check:

if (!pci_msi_enabled() || !dev || !dev->msi_enabled)
return;

and similarly pci_msi_shutdown() sets dev->msi_enabled to 0.

So my conclusion is it's safe to call pci_free_irq_vectors() twice for
the same device.

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