PCI: add an API to get node from vector

Next patch will use the API to get the node from vector for nvme device
Signed-off-by: NShaohua Li <shli@fb.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

drivers/pci/msi.c

@@ -1298,6 +1298,22 @@ const struct cpumask *pci_irq_get_affinity(struct pci_dev *dev, int nr)
 }
 EXPORT_SYMBOL(pci_irq_get_affinity);
 
+/**
+ * pci_irq_get_node - return the numa node of a particular msi vector
+ * @pdev:	PCI device to operate on
+ * @vec:	device-relative interrupt vector index (0-based).
+ */
+int pci_irq_get_node(struct pci_dev *pdev, int vec)
+{
+	const struct cpumask *mask;
+
+	mask = pci_irq_get_affinity(pdev, vec);
+	if (mask)
+		return local_memory_node(cpu_to_node(cpumask_first(mask)));
+	return dev_to_node(&pdev->dev);
+}
+EXPORT_SYMBOL(pci_irq_get_node);
+
 struct pci_dev *msi_desc_to_pci_dev(struct msi_desc *desc)
 {
 	return to_pci_dev(desc->dev);

include/linux/pci.h

@@ -1323,6 +1323,7 @@ int pci_alloc_irq_vectors_affinity(struct pci_dev *dev, unsigned int min_vecs,
 void pci_free_irq_vectors(struct pci_dev *dev);
 int pci_irq_vector(struct pci_dev *dev, unsigned int nr);
 const struct cpumask *pci_irq_get_affinity(struct pci_dev *pdev, int vec);
+int pci_irq_get_node(struct pci_dev *pdev, int vec);
 
 #else
 static inline int pci_msi_vec_count(struct pci_dev *dev) { return -ENOSYS; }
@@ -1370,6 +1371,11 @@ static inline const struct cpumask *pci_irq_get_affinity(struct pci_dev *pdev,
 {
 	return cpu_possible_mask;
 }
+
+static inline int pci_irq_get_node(struct pci_dev *pdev, int vec)
+{
+	return first_online_node;
+}
 #endif
 
 static inline int