From patchwork Mon Jul 27 10:46:44 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bastien Nocera X-Patchwork-Id: 11686729 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 CCDB91575 for ; Mon, 27 Jul 2020 10:46:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BCA9C2074F for ; Mon, 27 Jul 2020 10:46:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728266AbgG0Kqu (ORCPT ); Mon, 27 Jul 2020 06:46:50 -0400 Received: from relay7-d.mail.gandi.net ([217.70.183.200]:49177 "EHLO relay7-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727897AbgG0Kqt (ORCPT ); Mon, 27 Jul 2020 06:46:49 -0400 X-Originating-IP: 82.255.60.242 Received: from classic.redhat.com (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 878AB2000E; Mon, 27 Jul 2020 10:46:47 +0000 (UTC) From: Bastien Nocera To: linux-usb@vger.kernel.org Cc: Greg Kroah-Hartman , Alan Stern , Bastien Nocera Subject: [PATCH v6 3/3] USB: Fix device driver race Date: Mon, 27 Jul 2020 12:46:44 +0200 Message-Id: <20200727104644.149873-3-hadess@hadess.net> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200727104644.149873-1-hadess@hadess.net> References: <20200727104644.149873-1-hadess@hadess.net> 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 ("USB: Select better matching USB drivers when available") Signed-off-by: Bastien Nocera Acked-by: Alan Stern --- Changes since v5: - Throw error when device_reprobe() fails Changes since v4: - Add commit subject to "fixes" section - Clarify conditional that checks for generic driver - Remove check duplicated inside the loop 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 | 40 +++++++++++++++++++++++++++++++++++++-- 1 file changed, 38 insertions(+), 2 deletions(-) diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c index f81606c6a35b..7e73e989645b 100644 --- a/drivers/usb/core/driver.c +++ b/drivers/usb/core/driver.c @@ -905,6 +905,35 @@ static int usb_uevent(struct device *dev, struct kobj_uevent_env *env) return 0; } +static bool is_dev_usb_generic_driver(struct device *dev) +{ + struct usb_device_driver *udd = dev->driver ? + to_usb_device_driver(dev->driver) : NULL; + + return udd == &usb_generic_driver; +} + +static int __usb_bus_reprobe_drivers(struct device *dev, void *data) +{ + struct usb_device_driver *new_udriver = data; + struct usb_device *udev; + int ret; + + if (!is_dev_usb_generic_driver(dev)) + 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)) + return 0; + + ret = device_reprobe(dev); + if (ret && ret != -EPROBE_DEFER) + dev_err(dev, "Failed to reprobe device (error %d)\n", ret); + + return 0; +} + /** * usb_register_device_driver - register a USB device (not interface) driver * @new_udriver: USB operations for the device driver @@ -934,13 +963,20 @@ 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 + */ + 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; }