From patchwork Fri Jul 24 08:59:39 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bastien Nocera X-Patchwork-Id: 11682749 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1E9F913B4 for ; Fri, 24 Jul 2020 08:59:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 062E620748 for ; Fri, 24 Jul 2020 08:59:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727032AbgGXI7n (ORCPT ); Fri, 24 Jul 2020 04:59:43 -0400 Received: from relay7-d.mail.gandi.net ([217.70.183.200]:59981 "EHLO relay7-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726753AbgGXI7n (ORCPT ); Fri, 24 Jul 2020 04:59:43 -0400 X-Originating-IP: 82.255.60.242 Received: from classic (lns-bzn-39-82-255-60-242.adsl.proxad.net [82.255.60.242]) (Authenticated sender: hadess@hadess.net) by relay7-d.mail.gandi.net (Postfix) with ESMTPSA id 88EAE20009; Fri, 24 Jul 2020 08:59:40 +0000 (UTC) Message-ID: Subject: [PATCH v4] USB: Fix device driver race From: Bastien Nocera To: linux-usb@vger.kernel.org Cc: Greg Kroah-Hartman , Alan Stern Date: Fri, 24 Jul 2020 10:59:39 +0200 User-Agent: Evolution 3.36.3 (3.36.3-1.fc32) MIME-Version: 1.0 Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org When a new device with a specialised device driver is plugged in, the new driver will be modprobe()'d but the driver core will attach the "generic" driver to the device. After that, nothing will trigger a reprobe when the modprobe()'d device driver has finished initialising, as the device has the "generic" driver attached to it. Trigger a reprobe ourselves when new specialised drivers get registered. Fixes: 88b7381a939d Signed-off-by: Bastien Nocera --- Changes since v3: - Only reprobe devices that could use the new driver - Many code fixes Changes since v2: - Fix formatting Changes since v1: - Simplified after Alan Stern's comments and some clarifications from Benjamin Tissoires. drivers/usb/core/driver.c | 32 ++++++++++++++++++++++++++++++-- 1 file changed, 30 insertions(+), 2 deletions(-) diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c index f81606c6a35b..6731a8e104bc 100644 --- a/drivers/usb/core/driver.c +++ b/drivers/usb/core/driver.c @@ -905,6 +905,27 @@ static int usb_uevent(struct device *dev, struct kobj_uevent_env *env) return 0; } +static int __usb_bus_reprobe_drivers(struct device *dev, void *data) +{ + struct usb_device_driver *new_udriver = data; + struct usb_device_driver *udriver; + struct usb_device *udev; + + if (!dev->driver) + return 0; + + udriver = to_usb_device_driver(dev->driver); + if (udriver != &usb_generic_driver) + return 0; + + udev = to_usb_device(dev); + if (usb_device_match_id(udev, new_udriver->id_table) != NULL || + (new_udriver->match && new_udriver->match(udev) == 0)) + device_reprobe(dev); + + return 0; +} + /** * usb_register_device_driver - register a USB device (not interface) driver * @new_udriver: USB operations for the device driver @@ -934,13 +955,20 @@ int usb_register_device_driver(struct usb_device_driver *new_udriver, retval = driver_register(&new_udriver->drvwrap.driver); - if (!retval) + if (!retval) { pr_info("%s: registered new device driver %s\n", usbcore_name, new_udriver->name); - else + /* Check whether any device could be better served with + * this new driver + */ + if (new_udriver->match || new_udriver->id_table) + bus_for_each_dev(&usb_bus_type, NULL, new_udriver, + __usb_bus_reprobe_drivers); + } else { printk(KERN_ERR "%s: error %d registering device " " driver %s\n", usbcore_name, retval, new_udriver->name); + } return retval; }