PCI/MSI: Unbreak pci_irq_get_affinity()

The recent cleanup of pci_irq_get_affinity() broke the function for PCI/MSI-X and indices > 0. Only the MSI descriptor for PCI/MSI has more than one affinity mask which can be retrieved via the MSI index. PCI/MSI-X has one descriptor per vector and each has a single affinity mask. Use index 0 when accessing the affinity mask in the MSI descriptor when MSI-X is enabled. Fixes: f482359 ("PCI/MSI: Simplify pci_irq_get_affinity()") Reported-by: Nathan Chancellor <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Tested-by: Nathan Chancellor <[email protected]> Link: https://lore.kernel.org/r/87v8zm9pmd.ffs@tglx
dabrace · Dec 18, 2021 · d558285 · d558285
1 parent cd6cf06
commit d558285
Showing 1 changed file with 8 additions and 2 deletions.
diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c
@@ -1100,7 +1100,7 @@ EXPORT_SYMBOL(pci_irq_vector);
  */
 const struct cpumask *pci_irq_get_affinity(struct pci_dev *dev, int nr)
 {
-	int irq = pci_irq_vector(dev, nr);
+	int idx, irq = pci_irq_vector(dev, nr);
 	struct msi_desc *desc;
 
 	if (WARN_ON_ONCE(irq <= 0))
@@ -1113,7 +1113,13 @@ const struct cpumask *pci_irq_get_affinity(struct pci_dev *dev, int nr)
 
 	if (WARN_ON_ONCE(!desc->affinity))
 		return NULL;
-	return &desc->affinity[nr].mask;
+
+	/*
+	 * MSI has a mask array in the descriptor.
+	 * MSI-X has a single mask.
+	 */
+	idx = dev->msi_enabled ? nr : 0;
+	return &desc->affinity[idx].mask;
 }
 EXPORT_SYMBOL(pci_irq_get_affinity);