From patchwork Tue Mar 22 10:39:27 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 600712 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 3qTqHv237Tz9ryQ; Tue, 22 Mar 2016 21:51:23 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1aiJuC-0006zm-1S; Tue, 22 Mar 2016 10:51:20 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1aiJl6-0002f7-VM for kernel-team@lists.ubuntu.com; Tue, 22 Mar 2016 10:41:56 +0000 Received: from av-217-129-130-179.netvisao.pt ([217.129.130.179] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1aiJl6-0000gQ-FY; Tue, 22 Mar 2016 10:41:56 +0000 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com 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 Cc: Marc Kleine-Budde , Gerhard Uttenthaler X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com 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); } }