From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CB741C46460 for ; Sun, 12 Aug 2018 22:46:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7D2DB21748 for ; Sun, 12 Aug 2018 22:46:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7D2DB21748 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=rowland.harvard.edu Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728078AbeHMB0F (ORCPT ); Sun, 12 Aug 2018 21:26:05 -0400 Received: from netrider.rowland.org ([192.131.102.5]:38673 "HELO netrider.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1727774AbeHMB0F (ORCPT ); Sun, 12 Aug 2018 21:26:05 -0400 Received: (qmail 23350 invoked by uid 500); 12 Aug 2018 18:46:34 -0400 Received: from localhost (sendmail-bs@127.0.0.1) by localhost with SMTP; 12 Aug 2018 18:46:34 -0400 Date: Sun, 12 Aug 2018 18:46:34 -0400 (EDT) From: Alan Stern X-X-Sender: stern@netrider.rowland.org To: Tom Todd cc: gregkh@linuxfoundation.org, , , , , Subject: Re: [PATCH v2] USB: core: devio: Restructured proc_ioctl for readability In-Reply-To: <20180812222653.3341-1-thomas.m.a.todd@gmail.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 12 Aug 2018, Tom Todd wrote: > On, Sun, 12 Aug 2018 11:34:59 -0700 Joe Perches wrote: > >On Sun, 2018-08-12 at 19:06 +0100, Tom Todd wrote: > >> Fixed a code styling issue > >while it's OK to fix style only issues, it's much better > >to reorganize the code for reader clarity. > > Ok, thank you, I've taken your suggestions and created the a new version > > Restructured method proc_ioctl for readability and fixed code style > errors. > > Signed-off-by: Tom Todd "Style fixes" that introduce bugs are quite annoying... > --- > drivers/usb/core/devio.c | 67 ++++++++++++++++++++++------------------ > 1 file changed, 37 insertions(+), 30 deletions(-) > > diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c > index 476dcc5f2da3..740e60e086e2 100644 > --- a/drivers/usb/core/devio.c > +++ b/drivers/usb/core/devio.c > @@ -2117,46 +2117,52 @@ static int proc_ioctl(struct usb_dev_state *ps, struct usbdevfs_ioctl *ctl) > /* alloc buffer */ > size = _IOC_SIZE(ctl->ioctl_code); > if (size > 0) { > - buf = kmalloc(size, GFP_KERNEL); > - if (buf == NULL) > - return -ENOMEM; > - if ((_IOC_DIR(ctl->ioctl_code) & _IOC_WRITE)) { > - if (copy_from_user(buf, ctl->data, size)) { > - kfree(buf); > + if (_IOC_DIR(ctl->ioctl_code) & _IOC_WRITE) { > + buf = memdup_user(ctl->data, size); > + if (!buf) > return -EFAULT; > - } > } else { > - memset(buf, 0, size); > + buf = kmalloc(size, GFP_KERNEL); > + if (!buf) > + return -ENOMEM; Where do the contents of buf get set to 0 now? > } > } > > if (!connected(ps)) { > - kfree(buf); > - return -ENODEV; > + retval = -ENODEV; > + goto exit; > } > > - if (ps->dev->state != USB_STATE_CONFIGURED) > + if (ps->dev->state != USB_STATE_CONFIGURED) { > retval = -EHOSTUNREACH; > - else if (!(intf = usb_ifnum_to_if(ps->dev, ctl->ifno))) > + goto exit; > + } > + > + intf = usb_ifnum_to_if(ps->dev, ctl->ifno); > + if (!intf) { > retval = -EINVAL; > - else switch (ctl->ioctl_code) { > + goto exit; > + } > > + switch (ctl->ioctl_code) { > /* disconnect kernel driver from interface */ > case USBDEVFS_DISCONNECT: > - if (intf->dev.driver) { > - driver = to_usb_driver(intf->dev.driver); > - dev_dbg(&intf->dev, "disconnect by usbfs\n"); > - usb_driver_release_interface(driver, intf); > - } else > + if (!intf->dev.driver) { > retval = -ENODATA; > + goto exit; > + } > + driver = to_usb_driver(intf->dev.driver); > + dev_dbg(&intf->dev, "disconnect by usbfs\n"); > + usb_driver_release_interface(driver, intf); > break; > > /* let kernel drivers try to (re)bind to the interface */ > case USBDEVFS_CONNECT: > - if (!intf->dev.driver) > - retval = device_attach(&intf->dev); > - else > + if (!intf->dev.driver) { Now !intf->dev.driver generates an error instead of working? > retval = -EBUSY; > + goto exit; > + } > + retval = device_attach(&intf->dev); > break; > > /* talk directly to the interface's driver */ > @@ -2165,20 +2171,21 @@ static int proc_ioctl(struct usb_dev_state *ps, struct usbdevfs_ioctl *ctl) > driver = to_usb_driver(intf->dev.driver); > if (driver == NULL || driver->unlocked_ioctl == NULL) { > retval = -ENOTTY; > - } else { > - retval = driver->unlocked_ioctl(intf, ctl->ioctl_code, buf); > - if (retval == -ENOIOCTLCMD) > - retval = -ENOTTY; > + goto exit; > } > + retval = driver->unlocked_ioctl(intf, ctl->ioctl_code, buf); > + if (retval == -ENOIOCTLCMD) { > + retval = -ENOTTY; > + goto exit; > + } > + break; > } > > /* cleanup and return */ > - if (retval >= 0 > - && (_IOC_DIR(ctl->ioctl_code) & _IOC_READ) != 0 > - && size > 0 > - && copy_to_user(ctl->data, buf, size) != 0) > + if (retval >= 0 && (_IOC_DIR(ctl->ioctl_code) & _IOC_READ) != 0 && > + size > 0 && copy_to_user(ctl->data, buf, size) != 0) > retval = -EFAULT; Isn't the style in this file to indent continuation lines by two tab stops? > - > +exit: > kfree(buf); > return retval; > } Alan Stern