From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932356AbcA2Bby (ORCPT ); Thu, 28 Jan 2016 20:31:54 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:33570 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752800AbcA2BYJ (ORCPT ); Thu, 28 Jan 2016 20:24:09 -0500 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: =?UTF-8?q?Bj=C3=B8rn=20Mork?= , "David S. Miller" , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 183/210] net: cdc_ncm: avoid changing RX/TX buffers on MTU changes Date: Thu, 28 Jan 2016 17:18:41 -0800 Message-Id: <1454030348-17736-184-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1454030348-17736-1-git-send-email-kamal@canonical.com> References: <1454030348-17736-1-git-send-email-kamal@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Extended-Stable: 3.19 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.19.8-ckt14 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: =?UTF-8?q?Bj=C3=B8rn=20Mork?= [ Upstream commit 1dfddff5fcd869fcab0c52fafae099dfa435a935 ] NCM buffer sizes are negotiated with the device independently of the network device MTU. The RX buffers are allocated by the usbnet framework based on the rx_urb_size value set by cdc_ncm. A single RX buffer can hold a number of MTU sized packets. The default usbnet change_mtu ndo only modifies rx_urb_size if it is equal to hard_mtu. And the cdc_ncm driver will set rx_urb_size and hard_mtu independently of each other, based on dwNtbInMaxSize and dwNtbOutMaxSize respectively. It was therefore assumed that usbnet_change_mtu() would never touch rx_urb_size. This failed to consider the case where dwNtbInMaxSize and dwNtbOutMaxSize happens to be equal. Fix by implementing an NCM specific change_mtu ndo, modifying the netdev MTU without touching the buffer size settings. Signed-off-by: Bjørn Mork Signed-off-by: David S. Miller Signed-off-by: Kamal Mostafa --- drivers/net/usb/cdc_mbim.c | 2 +- drivers/net/usb/cdc_ncm.c | 31 +++++++++++++++++++++++++++++++ include/linux/usb/cdc_ncm.h | 1 + 3 files changed, 33 insertions(+), 1 deletion(-) diff --git a/drivers/net/usb/cdc_mbim.c b/drivers/net/usb/cdc_mbim.c index 96fc8a5..ce4280b 100644 --- a/drivers/net/usb/cdc_mbim.c +++ b/drivers/net/usb/cdc_mbim.c @@ -100,7 +100,7 @@ static const struct net_device_ops cdc_mbim_netdev_ops = { .ndo_stop = usbnet_stop, .ndo_start_xmit = usbnet_start_xmit, .ndo_tx_timeout = usbnet_tx_timeout, - .ndo_change_mtu = usbnet_change_mtu, + .ndo_change_mtu = cdc_ncm_change_mtu, .ndo_set_mac_address = eth_mac_addr, .ndo_validate_addr = eth_validate_addr, .ndo_vlan_rx_add_vid = cdc_mbim_rx_add_vid, diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c index 8067b8f..0b481c3 100644 --- a/drivers/net/usb/cdc_ncm.c +++ b/drivers/net/usb/cdc_ncm.c @@ -41,6 +41,7 @@ #include #include #include +#include #include #include #include @@ -687,6 +688,33 @@ static void cdc_ncm_free(struct cdc_ncm_ctx *ctx) kfree(ctx); } +/* we need to override the usbnet change_mtu ndo for two reasons: + * - respect the negotiated maximum datagram size + * - avoid unwanted changes to rx and tx buffers + */ +int cdc_ncm_change_mtu(struct net_device *net, int new_mtu) +{ + struct usbnet *dev = netdev_priv(net); + struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0]; + int maxmtu = ctx->max_datagram_size - cdc_ncm_eth_hlen(dev); + + if (new_mtu <= 0 || new_mtu > maxmtu) + return -EINVAL; + net->mtu = new_mtu; + return 0; +} +EXPORT_SYMBOL_GPL(cdc_ncm_change_mtu); + +static const struct net_device_ops cdc_ncm_netdev_ops = { + .ndo_open = usbnet_open, + .ndo_stop = usbnet_stop, + .ndo_start_xmit = usbnet_start_xmit, + .ndo_tx_timeout = usbnet_tx_timeout, + .ndo_change_mtu = cdc_ncm_change_mtu, + .ndo_set_mac_address = eth_mac_addr, + .ndo_validate_addr = eth_validate_addr, +}; + int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_altsetting) { const struct usb_cdc_union_desc *union_desc = NULL; @@ -861,6 +889,9 @@ advance: /* add our sysfs attrs */ dev->net->sysfs_groups[0] = &cdc_ncm_sysfs_attr_group; + /* must handle MTU changes */ + dev->net->netdev_ops = &cdc_ncm_netdev_ops; + return 0; error2: diff --git a/include/linux/usb/cdc_ncm.h b/include/linux/usb/cdc_ncm.h index 7c9b484..e7827ae 100644 --- a/include/linux/usb/cdc_ncm.h +++ b/include/linux/usb/cdc_ncm.h @@ -133,6 +133,7 @@ struct cdc_ncm_ctx { }; u8 cdc_ncm_select_altsetting(struct usb_interface *intf); +int cdc_ncm_change_mtu(struct net_device *net, int new_mtu); int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_altsetting); void cdc_ncm_unbind(struct usbnet *dev, struct usb_interface *intf); struct sk_buff *cdc_ncm_fill_tx_frame(struct usbnet *dev, struct sk_buff *skb, __le32 sign); -- 1.9.1