From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933521AbbCQJWR (ORCPT ); Tue, 17 Mar 2015 05:22:17 -0400 Received: from ip4-83-240-67-251.cust.nbox.cz ([83.240.67.251]:59679 "EHLO ip4-83-240-18-248.cust.nbox.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753660AbbCQImj (ORCPT ); Tue, 17 Mar 2015 04:42:39 -0400 From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Aleksander Morgado , Mathias Nyman , Jiri Slaby Subject: [PATCH 3.12 117/175] xhci: fix reporting of 0-sized URBs in control endpoint Date: Tue, 17 Mar 2015 09:41:35 +0100 Message-Id: X-Mailer: git-send-email 2.3.0 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Aleksander Morgado 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit 45ba2154d12fc43b70312198ec47085f10be801a upstream. When a control transfer has a short data stage, the xHCI controller generates two transfer events: a COMP_SHORT_TX event that specifies the untransferred amount, and a COMP_SUCCESS event. But when the data stage is not short, only the COMP_SUCCESS event occurs. Therefore, xhci-hcd must set urb->actual_length to urb->transfer_buffer_length while processing the COMP_SUCCESS event, unless urb->actual_length was set already by a previous COMP_SHORT_TX event. The driver checks this by seeing whether urb->actual_length == 0, but this alone is the wrong test, as it is entirely possible for a short transfer to have an urb->actual_length = 0. This patch changes the xhci driver to rely on a new td->urb_length_set flag, which is set to true when a COMP_SHORT_TX event is received and the URB length updated at that stage. This fixes a bug which affected the HSO plugin, which relies on URBs with urb->actual_length == 0 to halt re-submitting the RX URB in the control endpoint. Signed-off-by: Aleksander Morgado Signed-off-by: Mathias Nyman Signed-off-by: Jiri Slaby --- drivers/usb/host/xhci-ring.c | 10 ++++++++-- drivers/usb/host/xhci.h | 3 +++ 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index 6f052daed694..6bf308798a2d 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -2100,7 +2100,7 @@ static int process_ctrl_td(struct xhci_hcd *xhci, struct xhci_td *td, if (event_trb != ep_ring->dequeue) { /* The event was for the status stage */ if (event_trb == td->last_trb) { - if (td->urb->actual_length != 0) { + if (td->urb_length_set) { /* Don't overwrite a previously set error code */ if ((*status == -EINPROGRESS || *status == 0) && @@ -2114,7 +2114,13 @@ static int process_ctrl_td(struct xhci_hcd *xhci, struct xhci_td *td, td->urb->transfer_buffer_length; } } else { - /* Maybe the event was for the data stage? */ + /* + * Maybe the event was for the data stage? If so, update + * already the actual_length of the URB and flag it as + * set, so that it is not overwritten in the event for + * the last TRB. + */ + td->urb_length_set = true; td->urb->actual_length = td->urb->transfer_buffer_length - EVENT_TRB_LEN(le32_to_cpu(event->transfer_len)); diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h index 43f0b2ef7b60..d14b3e17b906 100644 --- a/drivers/usb/host/xhci.h +++ b/drivers/usb/host/xhci.h @@ -1,3 +1,4 @@ + /* * xHCI host controller driver * @@ -1284,6 +1285,8 @@ struct xhci_td { struct xhci_segment *start_seg; union xhci_trb *first_trb; union xhci_trb *last_trb; + /* actual_length of the URB has already been set */ + bool urb_length_set; }; /* xHCI command default timeout value */ -- 2.3.0