PCI/MSI: Move pci_irq_vector() to api.c

To disentangle the maze in msi.c, all exported device-driver MSI APIs are
now to be grouped in one file, api.c.

Move pci_irq_vector() and let its kernel-doc match the rest of the file.
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20221111122014.984490384@linutronix.de

drivers/pci/msi/api.c

@@ -182,3 +182,26 @@ int pci_alloc_irq_vectors_affinity(struct pci_dev *dev, unsigned int min_vecs,
 	return nvecs;
 }
 EXPORT_SYMBOL(pci_alloc_irq_vectors_affinity);
+
+/**
+ * pci_irq_vector() - Get Linux IRQ number of a device interrupt vector
+ * @dev: the PCI device to operate on
+ * @nr:  device-relative interrupt vector index (0-based); has different
+ *       meanings, depending on interrupt mode
+ *         MSI-X        the index in the MSI-X vector table
+ *         MSI          the index of the enabled MSI vectors
+ *         INTx         must be 0
+ *
+ * Return: the Linux IRQ number, or -EINVAL if @nr is out of range
+ */
+int pci_irq_vector(struct pci_dev *dev, unsigned int nr)
+{
+	unsigned int irq;
+
+	if (!dev->msi_enabled && !dev->msix_enabled)
+		return !nr ? dev->irq : -EINVAL;
+
+	irq = msi_get_virq(&dev->dev, nr);
+	return irq ? irq : -EINVAL;
+}
+EXPORT_SYMBOL(pci_irq_vector);

drivers/pci/msi/msi.c

@@ -899,30 +899,6 @@ void pci_free_irq_vectors(struct pci_dev *dev)
 }
 EXPORT_SYMBOL(pci_free_irq_vectors);
 
-/**
- * pci_irq_vector - return Linux IRQ number of a device vector
- * @dev:	PCI device to operate on
- * @nr:		Interrupt vector index (0-based)
- *
- * @nr has the following meanings depending on the interrupt mode:
- *   MSI-X:	The index in the MSI-X vector table
- *   MSI:	The index of the enabled MSI vectors
- *   INTx:	Must be 0
- *
- * Return: The Linux interrupt number or -EINVAl if @nr is out of range.
- */
-int pci_irq_vector(struct pci_dev *dev, unsigned int nr)
-{
-	unsigned int irq;
-
-	if (!dev->msi_enabled && !dev->msix_enabled)
-		return !nr ? dev->irq : -EINVAL;
-
-	irq = msi_get_virq(&dev->dev, nr);
-	return irq ? irq : -EINVAL;
-}
-EXPORT_SYMBOL(pci_irq_vector);
-
 /**
  * pci_irq_get_affinity - return the affinity of a particular MSI vector
  * @dev:	PCI device to operate on