Re: [patch 29/37] PCI/MSI: Use __msi_get_virq() in pci_get_vector()

Marc Zyngier
2021-11-28T19:39:51Z

On Sat, 27 Nov 2021 01:22:03 +0000,
Thomas Gleixner <tglx@linutronix.de> wrote:
>
> Use __msi_get_vector() and handle the return values to be compatible.
>
> No functional change intended.

You wish ;-).

[ 15.779540] pcieport 0001:00:01.0: AER: request AER IRQ -22 failed

Notice how amusing the IRQ number is?

>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
> drivers/pci/msi/msi.c | 25 +++++--------------------
> 1 file changed, 5 insertions(+), 20 deletions(-)
>
> --- a/drivers/pci/msi/msi.c
> +++ b/drivers/pci/msi/msi.c
> @@ -1023,28 +1023,13 @@ EXPORT_SYMBOL(pci_free_irq_vectors);
> */
> int pci_irq_vector(struct pci_dev *dev, unsigned int nr)
> {
> - if (dev->msix_enabled) {
> - struct msi_desc *entry;
> + int irq = __msi_get_virq(&dev->dev, nr);
>
> - for_each_pci_msi_entry(entry, dev) {
> - if (entry->msi_index == nr)
> - return entry->irq;
> - }
> - WARN_ON_ONCE(1);
> - return -EINVAL;
> + switch (irq) {
> + case -ENODEV: return !nr ? dev->irq : -EINVAL;
> + case -ENOENT: return -EINVAL;
> }
> -
> - if (dev->msi_enabled) {
> - struct msi_desc *entry = first_pci_msi_entry(dev);
> -
> - if (WARN_ON_ONCE(nr >= entry->nvec_used))
> - return -EINVAL;
> - } else {
> - if (WARN_ON_ONCE(nr > 0))
> - return -EINVAL;
> - }
> -
> - return dev->irq + nr;
> + return irq;
> }
> EXPORT_SYMBOL(pci_irq_vector);

I worked around it with the hack below, but I doubt this is the real
thing. portdrv_core.c does complicated things, and I don't completely
understand its logic.

M.

diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c
index 1f72bc734226..b15278a5fb4b 100644
--- a/drivers/pci/msi/msi.c
+++ b/drivers/pci/msi/msi.c
@@ -1092,8 +1092,9 @@ int pci_irq_vector(struct pci_dev *dev, unsigned int nr)
int irq = __msi_get_virq(&dev->dev, nr);

switch (irq) {
- case -ENODEV: return !nr ? dev->irq : -EINVAL;
- case -ENOENT: return -EINVAL;
+ case -ENOENT:
+ case -ENODEV:
+ return !nr ? dev->irq : -EINVAL;
}
return irq;
}

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