Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1162399AbbKTQ1j (ORCPT ); Fri, 20 Nov 2015 11:27:39 -0500 Received: from iolanthe.rowland.org ([192.131.102.54]:43840 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1760171AbbKTQ1h (ORCPT ); Fri, 20 Nov 2015 11:27:37 -0500 Date: Fri, 20 Nov 2015 11:27:36 -0500 (EST) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Marek Szyprowski cc: linux-usb@vger.kernel.org, , Ruslan Bilovol , Bartlomiej Zolnierkiewicz Subject: Re: [PATCH v6 4/4] usb: gadget: udc-core: independent registration of gadgets and gadget drivers In-Reply-To: <1448009652-14716-5-git-send-email-m.szyprowski@samsung.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1953 Lines: 55 On Fri, 20 Nov 2015, Marek Szyprowski wrote: > From: Ruslan Bilovol > > Change behavior during registration of gadgets and > gadget drivers in udc-core. Instead of previous > approach when for successful probe of usb gadget driver > at least one usb gadget should be already registered > use another one where gadget drivers and gadgets > can be registered in udc-core independently. > > Independent registration of gadgets and gadget drivers > is useful for built-in into kernel gadget and gadget > driver case - because it's possible that gadget is > really probed only on late_init stage (due to deferred > probe) whereas gadget driver's probe is silently failed > on module_init stage due to no any UDC added. > > Also it is useful for modules case - now there is no > difference what module to insert first: gadget module > or gadget driver one. > > Tested-by: Maxime Ripard > Signed-off-by: Ruslan Bilovol > [simplified code as requested by Alan Stern and Felipe Balbi] > Signed-off-by: Marek Szyprowski ... > @@ -475,9 +492,16 @@ void usb_del_gadget_udc(struct usb_gadget *gadget) > list_del(&udc->list); > mutex_unlock(&udc_lock); > > - if (udc->driver) > + if (udc->driver) { > + struct usb_gadget_driver *driver = udc->driver; > + > usb_gadget_remove_driver(udc); > > + mutex_lock(&udc_lock); > + list_add(&driver->pending, &gadget_driver_pending_list); > + mutex_unlock(&udc_lock); > + } It looks like there is a race here with usb_gadget_unregister_driver(). Would it be okay to hold the udc_lock mutex throughout the whole "if" statement? Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/