From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S938030AbdAJNrE (ORCPT ); Tue, 10 Jan 2017 08:47:04 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:32966 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1033738AbdAJNqx (ORCPT ); Tue, 10 Jan 2017 08:46:53 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Krzysztof Opasiak , Felipe Balbi Subject: [PATCH 4.9 033/206] usb: gadget: composite: Test get_alt() presence instead of set_alt() Date: Tue, 10 Jan 2017 14:35:16 +0100 Message-Id: <20170110131504.161757373@linuxfoundation.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170110131502.767555407@linuxfoundation.org> References: <20170110131502.767555407@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Krzysztof Opasiak commit 7e4da3fcf7c9fe042f2f7cb7bf23861a899b4a8f upstream. By convention (according to doc) if function does not provide get_alt() callback composite framework should assume that it has only altsetting 0 and should respond with error if host tries to set other one. After commit dd4dff8b035f ("USB: composite: Fix bug: should test set_alt function pointer before use it") we started checking set_alt() callback instead of get_alt(). This check is useless as we check if set_alt() is set inside usb_add_function() and fail if it's NULL. Let's fix this check and move comment about why we check the get method instead of set a little bit closer to prevent future false fixes. Fixes: dd4dff8b035f ("USB: composite: Fix bug: should test set_alt function pointer before use it") Signed-off-by: Krzysztof Opasiak Signed-off-by: Felipe Balbi Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/composite.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) --- a/drivers/usb/gadget/composite.c +++ b/drivers/usb/gadget/composite.c @@ -1694,9 +1694,7 @@ composite_setup(struct usb_gadget *gadge value = min(w_length, (u16) 1); break; - /* function drivers must handle get/set altsetting; if there's - * no get() method, we know only altsetting zero works. - */ + /* function drivers must handle get/set altsetting */ case USB_REQ_SET_INTERFACE: if (ctrl->bRequestType != USB_RECIP_INTERFACE) goto unknown; @@ -1705,7 +1703,13 @@ composite_setup(struct usb_gadget *gadge f = cdev->config->interface[intf]; if (!f) break; - if (w_value && !f->set_alt) + + /* + * If there's no get_alt() method, we know only altsetting zero + * works. There is no need to check if set_alt() is not NULL + * as we check this in usb_add_function(). + */ + if (w_value && !f->get_alt) break; value = f->set_alt(f, w_index, w_value); if (value == USB_GADGET_DELAYED_STATUS) {