RDMA/core: Expose pkeys sysfs files only if pkey_tbl_len is set

Expose the pkeys sysfs files only if the pkey_tbl_len is set by the
providers.

Link: https://lore.kernel.org/r/20200714183414.61069-2-kamalheib1@gmail.comSigned-off-by: NKamal Heib <kamalheib1@gmail.com>
Signed-off-by: NJason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/core/sysfs.c

@@ -58,7 +58,7 @@ struct ib_port {
 	struct ib_device      *ibdev;
 	struct gid_attr_group *gid_attr_group;
 	struct attribute_group gid_group;
-	struct attribute_group pkey_group;
+	struct attribute_group *pkey_group;
 	struct attribute_group *pma_table;
 	struct attribute_group *hw_stats_ag;
 	struct rdma_hw_stats   *hw_stats;
@@ -681,11 +681,16 @@ static void ib_port_release(struct kobject *kobj)
 		kfree(p->gid_group.attrs);
 	}
 
-	if (p->pkey_group.attrs) {
-		for (i = 0; (a = p->pkey_group.attrs[i]); ++i)
-			kfree(a);
+	if (p->pkey_group) {
+		if (p->pkey_group->attrs) {
+			for (i = 0; (a = p->pkey_group->attrs[i]); ++i)
+				kfree(a);
+
+			kfree(p->pkey_group->attrs);
+		}
 
-		kfree(p->pkey_group.attrs);
+		kfree(p->pkey_group);
+		p->pkey_group = NULL;
 	}
 
 	kfree(p);
@@ -1118,17 +1123,26 @@ static int add_port(struct ib_core_device *coredev, int port_num)
 	if (ret)
 		goto err_free_gid_type;
 
-	p->pkey_group.name  = "pkeys";
-	p->pkey_group.attrs = alloc_group_attrs(show_port_pkey,
-						attr.pkey_tbl_len);
-	if (!p->pkey_group.attrs) {
-		ret = -ENOMEM;
-		goto err_remove_gid_type;
+	if (attr.pkey_tbl_len) {
+		p->pkey_group = kzalloc(sizeof(*p->pkey_group), GFP_KERNEL);
+		if (!p->pkey_group) {
+			ret = -ENOMEM;
+			goto err_remove_gid_type;
+		}
+
+		p->pkey_group->name  = "pkeys";
+		p->pkey_group->attrs = alloc_group_attrs(show_port_pkey,
+							 attr.pkey_tbl_len);
+		if (!p->pkey_group->attrs) {
+			ret = -ENOMEM;
+			goto err_free_pkey_group;
+		}
+
+		ret = sysfs_create_group(&p->kobj, p->pkey_group);
+		if (ret)
+			goto err_free_pkey;
 	}
 
-	ret = sysfs_create_group(&p->kobj, &p->pkey_group);
-	if (ret)
-		goto err_free_pkey;
 
 	if (device->ops.init_port && is_full_dev) {
 		ret = device->ops.init_port(device, port_num, &p->kobj);
@@ -1150,14 +1164,20 @@ static int add_port(struct ib_core_device *coredev, int port_num)
 	return 0;
 
 err_remove_pkey:
-	sysfs_remove_group(&p->kobj, &p->pkey_group);
+	if (p->pkey_group)
+		sysfs_remove_group(&p->kobj, p->pkey_group);
 
 err_free_pkey:
-	for (i = 0; i < attr.pkey_tbl_len; ++i)
-		kfree(p->pkey_group.attrs[i]);
+	if (p->pkey_group) {
+		for (i = 0; i < attr.pkey_tbl_len; ++i)
+			kfree(p->pkey_group->attrs[i]);
+
+		kfree(p->pkey_group->attrs);
+		p->pkey_group->attrs = NULL;
+	}
 
-	kfree(p->pkey_group.attrs);
-	p->pkey_group.attrs = NULL;
+err_free_pkey_group:
+	kfree(p->pkey_group);
 
 err_remove_gid_type:
 	sysfs_remove_group(&p->gid_attr_group->kobj,
@@ -1317,7 +1337,8 @@ void ib_free_port_attrs(struct ib_core_device *coredev)
 
 		if (port->pma_table)
 			sysfs_remove_group(p, port->pma_table);
-		sysfs_remove_group(p, &port->pkey_group);
+		if (port->pkey_group)
+			sysfs_remove_group(p, port->pkey_group);
 		sysfs_remove_group(p, &port->gid_group);
 		sysfs_remove_group(&port->gid_attr_group->kobj,
 				   &port->gid_attr_group->ndev);