From patchwork Tue May 10 15:51:29 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alan Stern X-Patchwork-Id: 12845205 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3CA36C433FE for ; Tue, 10 May 2022 15:55:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346873AbiEJP67 (ORCPT ); Tue, 10 May 2022 11:58:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59708 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347979AbiEJP62 (ORCPT ); Tue, 10 May 2022 11:58:28 -0400 Received: from netrider.rowland.org (netrider.rowland.org [192.131.102.5]) by lindbergh.monkeyblade.net (Postfix) with SMTP id 3677DE7320 for ; Tue, 10 May 2022 08:51:29 -0700 (PDT) Received: (qmail 165588 invoked by uid 1000); 10 May 2022 11:51:29 -0400 Date: Tue, 10 May 2022 11:51:29 -0400 From: Alan Stern To: Greg KH Cc: Geert Uytterhoeven , Felipe Balbi , USB mailing list Subject: [PATCH] USB: gadget: Add ID numbers to gadget names Message-ID: References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Putting USB gadgets on a new bus of their own encounters a problem when multiple gadgets are present: They all have the same name! The driver core fails with a "sys: cannot create duplicate filename" error when creating any of the /sys/bus/gadget/devices/ symbolic links after the first. This patch fixes the problem by adding a ".N" suffix to each gadget's name when the gadget is registered (where N is a unique ID number), thus making the names distinct. Reported-and-tested-by: Geert Uytterhoeven Signed-off-by: Alan Stern Reviewed-by: Geert Uytterhoeven Fixes: fc274c1e9973 ("USB: gadget: Add a new bus for gadgets") --- [as1980] drivers/usb/gadget/udc/core.c | 16 ++++++++++++++-- include/linux/usb/gadget.h | 2 ++ 2 files changed, 16 insertions(+), 2 deletions(-) Index: usb-devel/drivers/usb/gadget/udc/core.c =================================================================== --- usb-devel.orig/drivers/usb/gadget/udc/core.c +++ usb-devel/drivers/usb/gadget/udc/core.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include @@ -23,6 +24,8 @@ #include "trace.h" +static DEFINE_IDA(gadget_id_numbers); + static struct bus_type gadget_bus_type; /** @@ -1248,7 +1251,6 @@ static void usb_udc_nop_release(struct d void usb_initialize_gadget(struct device *parent, struct usb_gadget *gadget, void (*release)(struct device *dev)) { - dev_set_name(&gadget->dev, "gadget"); INIT_WORK(&gadget->work, usb_gadget_state_work); gadget->dev.parent = parent; @@ -1304,12 +1306,21 @@ int usb_add_gadget(struct usb_gadget *ga usb_gadget_set_state(gadget, USB_STATE_NOTATTACHED); udc->vbus = true; + ret = ida_alloc(&gadget_id_numbers, GFP_KERNEL); + if (ret < 0) + goto err_del_udc; + gadget->id_number = ret; + dev_set_name(&gadget->dev, "gadget.%d", ret); + ret = device_add(&gadget->dev); if (ret) - goto err_del_udc; + goto err_free_id; return 0; + err_free_id: + ida_free(&gadget_id_numbers, gadget->id_number); + err_del_udc: flush_work(&gadget->work); device_del(&udc->dev); @@ -1417,6 +1428,7 @@ void usb_del_gadget(struct usb_gadget *g kobject_uevent(&udc->dev.kobj, KOBJ_REMOVE); flush_work(&gadget->work); device_del(&gadget->dev); + ida_free(&gadget_id_numbers, gadget->id_number); device_unregister(&udc->dev); } EXPORT_SYMBOL_GPL(usb_del_gadget); Index: usb-devel/include/linux/usb/gadget.h =================================================================== --- usb-devel.orig/include/linux/usb/gadget.h +++ usb-devel/include/linux/usb/gadget.h @@ -386,6 +386,7 @@ struct usb_gadget_ops { * @lpm_capable: If the gadget max_speed is FULL or HIGH, this flag * indicates that it supports LPM as per the LPM ECN & errata. * @irq: the interrupt number for device controller. + * @id_number: a unique ID number for ensuring that gadget names are distinct * * Gadgets have a mostly-portable "gadget driver" implementing device * functions, handling all usb configurations and interfaces. Gadget @@ -446,6 +447,7 @@ struct usb_gadget { unsigned connected:1; unsigned lpm_capable:1; int irq; + int id_number; }; #define work_to_gadget(w) (container_of((w), struct usb_gadget, work))