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: f48235900182 ("PCI/MSI: Simplify pci_irq_get_affinity()")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/87v8zm9pmd.ffs@tglx

diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c
index 71802410e2ab3b0491d8754f31198172587285a8..c19c7ca581868a366289932163621ad8ae794c34 100644 (file)
--- 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);