Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753088AbcKJFvB (ORCPT ); Thu, 10 Nov 2016 00:51:01 -0500 Received: from mail-yw0-f170.google.com ([209.85.161.170]:35892 "EHLO mail-yw0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752087AbcKJFu7 (ORCPT ); Thu, 10 Nov 2016 00:50:59 -0500 MIME-Version: 1.0 In-Reply-To: <20161109153521.GA20272@vnote> References: <20161109153521.GA20272@vnote> From: Baolin Wang Date: Thu, 10 Nov 2016 13:50:58 +0800 Message-ID: Subject: Re: [PATCH v4] USB hub_probe: rework ugly goto-into-compound-statement To: Eugene Korenevsky , LKML , USB , Greg Kroah-Hartman Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3609 Lines: 101 Hi, On 9 November 2016 at 23:35, Eugene Korenevsky wrote: > Rework smelling code (goto inside compound statement). Perhaps this is > legacy. Anyway such code is not appropriate for Linux kernel. > > Changes since v3: fix typo > Changes since v2: extract the code to static function > Changes since v1: fix spaces instead of tab, add missing 'Signed-off-by' > > Signed-off-by: Eugene Korenevsky > --- > drivers/usb/core/hub.c | 35 ++++++++++++++++++----------------- > 1 file changed, 18 insertions(+), 17 deletions(-) > > diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c > index cbb1467..b770c8d 100644 > --- a/drivers/usb/core/hub.c > +++ b/drivers/usb/core/hub.c > @@ -1722,10 +1722,25 @@ static void hub_disconnect(struct usb_interface *intf) > kref_put(&hub->kref, hub_release); > } > > +static int hub_check_descriptor_sanity(struct usb_host_interface *desc) > +{ > + /* 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) > + return 0; > + > + /* Multiple endpoints? What kind of mutant ninja-hub is this? */ > + if (desc->desc.bNumEndpoints != 1) > + return 0; We usually return 0 as successful result, can you return kernel error number if we check the descriptor failed? Or change the return value of the function as bool type. > + > + /* If it's not an interrupt in endpoint, we'd better punt! */ > + return usb_endpoint_is_int_in(&desc->endpoint[0].desc); > +} > + > static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id) > { > struct usb_host_interface *desc; > - struct usb_endpoint_descriptor *endpoint; > struct usb_device *hdev; > struct usb_hub *hub; > > @@ -1800,25 +1815,11 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id) > } > #endif > > - /* 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: > + if (!hub_check_descriptor_sanity(desc)) { > 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"); > > @@ -1845,7 +1846,7 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id) > if (id->driver_info & HUB_QUIRK_CHECK_PORT_AUTOSUSPEND) > hub->quirk_check_port_auto_suspend = 1; > > - if (hub_configure(hub, endpoint) >= 0) > + if (hub_configure(hub, &desc->endpoint[0].desc) >= 0) > return 0; > > hub_disconnect(intf); > -- > 2.10.2 > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-usb" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Baolin.wang Best Regards