blk-mq: provide a default queue mapping for PCI device

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/include/linux/blk-mq-pci.h b/include/linux/blk-mq-pci.h
new file mode 100644
index 0000000..6ab5952
--- /dev/null
+++ b/include/linux/blk-mq-pci.h
@@ -0,0 +1,9 @@
+#ifndef _LINUX_BLK_MQ_PCI_H
+#define _LINUX_BLK_MQ_PCI_H
+
+struct blk_mq_tag_set;
+struct pci_dev;
+
+int blk_mq_pci_map_queues(struct blk_mq_tag_set *set, struct pci_dev *pdev);
+
+#endif /* _LINUX_BLK_MQ_PCI_H */