Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932690AbcCVLSj (ORCPT ); Tue, 22 Mar 2016 07:18:39 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:56519 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758707AbcCVKl7 (ORCPT ); Tue, 22 Mar 2016 06:41:59 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Gerhard Uttenthaler , Marc Kleine-Budde , Luis Henriques Subject: [PATCH 3.16.y-ckt 038/142] can: ems_usb: Fix possible tx overflow Date: Tue, 22 Mar 2016 10:39:27 +0000 Message-Id: <1458643271-4227-39-git-send-email-luis.henriques@canonical.com> In-Reply-To: <1458643271-4227-1-git-send-email-luis.henriques@canonical.com> References: <1458643271-4227-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2538 Lines: 74 3.16.7-ckt26 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Gerhard Uttenthaler commit 90cfde46586d2286488d8ed636929e936c0c9ab2 upstream. This patch fixes the problem that more CAN messages could be sent to the interface as could be send on the CAN bus. This was more likely for slow baud rates. The sleeping _start_xmit was woken up in the _write_bulk_callback. Under heavy TX load this produced another bulk transfer without checking the free_slots variable and hence caused the overflow in the interface. Signed-off-by: Gerhard Uttenthaler Signed-off-by: Marc Kleine-Budde Signed-off-by: Luis Henriques --- drivers/net/can/usb/ems_usb.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/drivers/net/can/usb/ems_usb.c b/drivers/net/can/usb/ems_usb.c index 00f2534dde73..91a4312e5c34 100644 --- a/drivers/net/can/usb/ems_usb.c +++ b/drivers/net/can/usb/ems_usb.c @@ -117,6 +117,9 @@ MODULE_LICENSE("GPL v2"); */ #define EMS_USB_ARM7_CLOCK 8000000 +#define CPC_TX_QUEUE_TRIGGER_LOW 25 +#define CPC_TX_QUEUE_TRIGGER_HIGH 35 + /* * CAN-Message representation in a CPC_MSG. Message object type is * CPC_MSG_TYPE_CAN_FRAME or CPC_MSG_TYPE_RTR_FRAME or @@ -278,6 +281,11 @@ static void ems_usb_read_interrupt_callback(struct urb *urb) switch (urb->status) { case 0: dev->free_slots = dev->intr_in_buffer[1]; + if(dev->free_slots > CPC_TX_QUEUE_TRIGGER_HIGH){ + if (netif_queue_stopped(netdev)){ + netif_wake_queue(netdev); + } + } break; case -ECONNRESET: /* unlink */ @@ -529,8 +537,6 @@ static void ems_usb_write_bulk_callback(struct urb *urb) /* Release context */ context->echo_index = MAX_TX_URBS; - if (netif_queue_stopped(netdev)) - netif_wake_queue(netdev); } /* @@ -590,7 +596,7 @@ static int ems_usb_start(struct ems_usb *dev) int err, i; dev->intr_in_buffer[0] = 0; - dev->free_slots = 15; /* initial size */ + dev->free_slots = 50; /* initial size */ for (i = 0; i < MAX_RX_URBS; i++) { struct urb *urb = NULL; @@ -841,7 +847,7 @@ static netdev_tx_t ems_usb_start_xmit(struct sk_buff *skb, struct net_device *ne /* Slow down tx path */ if (atomic_read(&dev->active_tx_urbs) >= MAX_TX_URBS || - dev->free_slots < 5) { + dev->free_slots < CPC_TX_QUEUE_TRIGGER_LOW) { netif_stop_queue(netdev); } }