NTB: Correct debugfs to work with more than 1 NTB Device

Debugfs was setup in NTB to only have a single debugfs directory.  This
resulted in the leaking of debugfs directories and files when multiple
NTB devices were present, due to each device stomping on the variables
containing the previous device's values (thus preventing them from being
freed on cleanup).  Correct this by creating a secondary directory of
the PCI BDF for each device present, and nesting the previously existing
information in those directories.

Signed-off-by: Jon Mason <jon.mason@intel.com>
diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index f8d7081..c308915 100644
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -157,7 +157,6 @@
 	bool transport_link;
 	struct delayed_work link_work;
 	struct work_struct link_cleanup;
-	struct dentry *debugfs_dir;
 };
 
 enum {
@@ -824,12 +823,12 @@
 	qp->tx_max_frame = min(transport_mtu, tx_size / 2);
 	qp->tx_max_entry = tx_size / qp->tx_max_frame;
 
-	if (nt->debugfs_dir) {
+	if (ntb_query_debugfs(nt->ndev)) {
 		char debugfs_name[4];
 
 		snprintf(debugfs_name, 4, "qp%d", qp_num);
 		qp->debugfs_dir = debugfs_create_dir(debugfs_name,
-						     nt->debugfs_dir);
+						 ntb_query_debugfs(nt->ndev));
 
 		qp->debugfs_stats = debugfs_create_file("stats", S_IRUSR,
 							qp->debugfs_dir, qp,
@@ -857,11 +856,6 @@
 	if (!nt)
 		return -ENOMEM;
 
-	if (debugfs_initialized())
-		nt->debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
-	else
-		nt->debugfs_dir = NULL;
-
 	nt->ndev = ntb_register_transport(pdev, nt);
 	if (!nt->ndev) {
 		rc = -EIO;
@@ -907,7 +901,6 @@
 err1:
 	ntb_unregister_transport(nt->ndev);
 err:
-	debugfs_remove_recursive(nt->debugfs_dir);
 	kfree(nt);
 	return rc;
 }
@@ -921,16 +914,16 @@
 	nt->transport_link = NTB_LINK_DOWN;
 
 	/* verify that all the qp's are freed */
-	for (i = 0; i < nt->max_qps; i++)
+	for (i = 0; i < nt->max_qps; i++) {
 		if (!test_bit(i, &nt->qp_bitmap))
 			ntb_transport_free_queue(&nt->qps[i]);
+		debugfs_remove_recursive(nt->qps[i].debugfs_dir);
+	}
 
 	ntb_bus_remove(nt);
 
 	cancel_delayed_work_sync(&nt->link_work);
 
-	debugfs_remove_recursive(nt->debugfs_dir);
-
 	ntb_unregister_event_callback(nt->ndev);
 
 	pdev = ntb_query_pdev(nt->ndev);