IB/uverbs: Add devnode method to set path/mode

We want udev to create a device node under /dev/infiniband with
permission 0666 for uverbsX devices, so add a devnode method to set the
appropriate info.
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/infiniband/core/uverbs_main.c

@@ -824,6 +824,12 @@ static void ib_uverbs_remove_one(struct ib_device *device)
 	kfree(uverbs_dev);
 }
 
+static char *uverbs_devnode(struct device *dev, mode_t *mode)
+{
+	*mode = 0666;
+	return kasprintf(GFP_KERNEL, "infiniband/%s", dev_name(dev));
+}
+
 static int __init ib_uverbs_init(void)
 {
 	int ret;
@@ -842,6 +848,8 @@ static int __init ib_uverbs_init(void)
 		goto out_chrdev;
 	}
 
+	uverbs_class->devnode = uverbs_devnode;
+
 	ret = class_create_file(uverbs_class, &class_attr_abi_version.attr);
 	if (ret) {
 		printk(KERN_ERR "user_verbs: couldn't create abi_version attribute\n");