linux-kernel - [PATCH] USB hub_probe: refactor ugly goto-into-compound-statement

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Date:   Wed, 2 Nov 2016 19:29:40 +0300
From:   Eugene Korenevsky <ekorenevsky@...il.com>
To:     linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org
Cc:     Luiz Capitulino <lcapitulino@...hat.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Chase Metzger <chasemetzger15@...il.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Alan Stern <stern@...land.harvard.edu>,
        Mathias Nyman <mathias.nyman@...ux.intel.com>,
        Lu Baolu <baolu.lu@...ux.intel.com>,
        Oliver Neukum <oneukum@...e.com>, Hans Yang <hansy@...dia.com>
Subject: [PATCH] USB hub_probe: refactor ugly goto-into-compound-statement

Rework smelling code (goto inside compound statement). Perhaps this is legacy.
Anyway such code is not appropriate for Linux kernel.

---
 drivers/usb/core/hub.c | 24 +++++++++++-------------
 1 file changed, 11 insertions(+), 13 deletions(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index cbb1467..abd786b 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1802,23 +1802,21 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id)
 
 	/* Some hubs have a subclass of 1, which AFAICT according to the */
 	/*  specs is not defined, but it works */
-	if ((desc->desc.bInterfaceSubClass != 0) &&
-	    (desc->desc.bInterfaceSubClass != 1)) {
-descriptor_error:
+
+	/* Reject in following cases:
+	 * - Interface subclass is not 0 or 1
+	 * - Multiple endpoints
+	 * - Not an interrupt in endpoint
+	 */
+	endpoint = &desc->endpoint[0].desc;
+	if ((desc->desc.bInterfaceSubClass != 0 &&
+	     desc->desc.bInterfaceSubClass != 1) ||
+            desc->desc.bNumEndpoints != 1 ||
+            !usb_endpoint_is_int_in(endpoint)) {
 		dev_err(&intf->dev, "bad descriptor, ignoring hub\n");
 		return -EIO;
 	}
 
-	/* Multiple endpoints? What kind of mutant ninja-hub is this? */
-	if (desc->desc.bNumEndpoints != 1)
-		goto descriptor_error;
-
-	endpoint = &desc->endpoint[0].desc;
-
-	/* If it's not an interrupt in endpoint, we'd better punt! */
-	if (!usb_endpoint_is_int_in(endpoint))
-		goto descriptor_error;
-
 	/* We found a hub */
 	dev_info(&intf->dev, "USB hub found\n");
 
-- 
2.10.2