From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754855AbaDFXkj (ORCPT ); Sun, 6 Apr 2014 19:40:39 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:59454 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754744AbaDFXjG (ORCPT ); Sun, 6 Apr 2014 19:39:06 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Greg Kroah-Hartman" , "Paul Stewart" , "Aurelien Jacobs" , "Trond Wuellner" , "Eric Dumazet" , "Emil Goode" , "Grant Grundler" , "David S. Miller" Date: Mon, 07 Apr 2014 00:35:48 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 12/18] asix: asix_rx_fixup surgery to reduce skb truesizes In-Reply-To: X-SA-Exim-Connect-IP: 192.168.2.102 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.57-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet commit a9e0aca4b37885b5599e52211f098bd7f565e749 upstream. asix_rx_fixup() is complex, and does some unnecessary memory copies (at least on x86 where NET_IP_ALIGN is 0) Also, it tends to provide skbs with a big truesize (4096+256 with MTU=1500) to upper stack, so incoming trafic consume a lot of memory and I noticed early packet drops because we hit socket rcvbuf too fast. Switch to a different strategy, using copybreak so that we provide nice skbs to upper stack (including the NET_SKB_PAD to avoid future head reallocations in some paths) With this patch, I no longer see packets drops or tcp collapses on various tcp workload with a AX88772 adapter. Signed-off-by: Eric Dumazet Cc: Aurelien Jacobs Cc: Greg Kroah-Hartman Cc: Trond Wuellner Cc: Grant Grundler Cc: Paul Stewart Reviewed-by: Grant Grundler Reviewed-by: Grant Grundler Signed-off-by: David S. Miller [ Emil: Backported to 3.2: fixed small conflict ] Signed-off-by: Emil Goode Signed-off-by: Ben Hutchings --- drivers/net/usb/asix.c | 88 +++++++++++------------------------------------- 1 file changed, 20 insertions(+), 68 deletions(-) --- a/drivers/net/usb/asix.c +++ b/drivers/net/usb/asix.c @@ -306,88 +306,40 @@ asix_write_cmd_async(struct usbnet *dev, static int asix_rx_fixup(struct usbnet *dev, struct sk_buff *skb) { - u8 *head; - u32 header; - char *packet; - struct sk_buff *ax_skb; - u16 size; - - head = (u8 *) skb->data; - memcpy(&header, head, sizeof(header)); - le32_to_cpus(&header); - packet = head + sizeof(header); + int offset = 0; - skb_pull(skb, 4); + while (offset + sizeof(u32) < skb->len) { + struct sk_buff *ax_skb; + u16 size; + u32 header = get_unaligned_le32(skb->data + offset); - while (skb->len > 0) { - if ((header & 0x07ff) != ((~header >> 16) & 0x07ff)) - netdev_err(dev->net, "asix_rx_fixup() Bad Header Length\n"); + offset += sizeof(u32); /* get the packet length */ - size = (u16) (header & 0x000007ff); - - if ((skb->len) - ((size + 1) & 0xfffe) == 0) { - u8 alignment = (unsigned long)skb->data & 0x3; - if (alignment != 0x2) { - /* - * not 16bit aligned so use the room provided by - * the 32 bit header to align the data - * - * note we want 16bit alignment as MAC header is - * 14bytes thus ip header will be aligned on - * 32bit boundary so accessing ipheader elements - * using a cast to struct ip header wont cause - * an unaligned accesses. - */ - u8 realignment = (alignment + 2) & 0x3; - memmove(skb->data - realignment, - skb->data, - size); - skb->data -= realignment; - skb_set_tail_pointer(skb, size); - } - return 2; + size = (u16) (header & 0x7ff); + if (size != ((~header >> 16) & 0x07ff)) { + netdev_err(dev->net, "asix_rx_fixup() Bad Header Length\n"); + return 0; } - if (size > dev->net->mtu + ETH_HLEN + VLAN_HLEN) { + if ((size > dev->net->mtu + ETH_HLEN + VLAN_HLEN) || + (size + offset > skb->len)) { netdev_err(dev->net, "asix_rx_fixup() Bad RX Length %d\n", size); return 0; } - ax_skb = skb_clone(skb, GFP_ATOMIC); - if (ax_skb) { - u8 alignment = (unsigned long)packet & 0x3; - ax_skb->len = size; - - if (alignment != 0x2) { - /* - * not 16bit aligned use the room provided by - * the 32 bit header to align the data - */ - u8 realignment = (alignment + 2) & 0x3; - memmove(packet - realignment, packet, size); - packet -= realignment; - } - ax_skb->data = packet; - skb_set_tail_pointer(ax_skb, size); - usbnet_skb_return(dev, ax_skb); - } else { + ax_skb = netdev_alloc_skb_ip_align(dev->net, size); + if (!ax_skb) return 0; - } - - skb_pull(skb, (size + 1) & 0xfffe); - if (skb->len < sizeof(header)) - break; + skb_put(ax_skb, size); + memcpy(ax_skb->data, skb->data + offset, size); + usbnet_skb_return(dev, ax_skb); - head = (u8 *) skb->data; - memcpy(&header, head, sizeof(header)); - le32_to_cpus(&header); - packet = head + sizeof(header); - skb_pull(skb, 4); + offset += (size + 1) & 0xfffe; } - if (skb->len < 0) { + if (skb->len != offset) { netdev_err(dev->net, "asix_rx_fixup() Bad SKB Length %d\n", skb->len); return 0; @@ -1538,7 +1490,7 @@ static const struct driver_info ax88772_ .status = asix_status, .link_reset = ax88772_link_reset, .reset = ax88772_reset, - .flags = FLAG_ETHER | FLAG_FRAMING_AX | FLAG_LINK_INTR, + .flags = FLAG_ETHER | FLAG_FRAMING_AX | FLAG_LINK_INTR | FLAG_MULTI_PACKET, .rx_fixup = asix_rx_fixup, .tx_fixup = asix_tx_fixup, };