Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756780AbaJ1LOx (ORCPT ); Tue, 28 Oct 2014 07:14:53 -0400 Received: from mx0.aculab.com ([213.249.233.131]:45663 "HELO mx0.aculab.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1754831AbaJ1LOv (ORCPT ); Tue, 28 Oct 2014 07:14:51 -0400 From: David Laight To: =?utf-8?B?J0xvdGhhciBXYcOfbWFubic=?= , "netdev@vger.kernel.org" CC: "David S. Miller" , Russell King , Frank Li , "Fabio Estevam" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" Subject: RE: [PATCHv2 6/6] net: fec: fix regression on i.MX28 introduced by rx_copybreak support Thread-Topic: [PATCHv2 6/6] net: fec: fix regression on i.MX28 introduced by rx_copybreak support Thread-Index: AQHP8p5eP0jGHGIUnUypcxZpFUTH1pxFWcXA Date: Tue, 28 Oct 2014 11:12:30 +0000 Message-ID: <063D6719AE5E284EB5DD2968C1650D6D1C9E04C0@AcuExch.aculab.com> References: <1414494104-27943-1-git-send-email-LW@KARO-electronics.de> <1414494104-27943-7-git-send-email-LW@KARO-electronics.de> In-Reply-To: <1414494104-27943-7-git-send-email-LW@KARO-electronics.de> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.202.99.200] Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by nfs id s9SBExDp024283 From: Lothar Waßmann > commit 1b7bde6d659d ("net: fec: implement rx_copybreak to improve rx performance") > introduced a regression for i.MX28. The swap_buffer() function doing > the endian conversion of the received data on i.MX28 may access memory > beyond the actual packet size in the DMA buffer. fec_enet_copybreak() > does not copy those bytes, so that the last bytes of a packet may be > filled with invalid data after swapping. > This will likely lead to checksum errors on received packets. > E.g. when trying to mount an NFS rootfs: > UDP: bad checksum. From 192.168.1.225:111 to 192.168.100.73:44662 ulen 36 > > Do the byte swapping and copying to the new skb in one go if > necessary. > > Signed-off-by: Lothar Wamann > --- > drivers/net/ethernet/freescale/fec_main.c | 25 +++++++++++++++++++++---- > 1 file changed, 21 insertions(+), 4 deletions(-) > > diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c > index 404fb9d..b92324c 100644 > --- a/drivers/net/ethernet/freescale/fec_main.c > +++ b/drivers/net/ethernet/freescale/fec_main.c > @@ -339,6 +339,18 @@ static void *swap_buffer(void *bufaddr, int len) > return bufaddr; > } > > +static void *swap_buffer2(void *dst_buf, void *src_buf, int len) > +{ > + int i; > + unsigned int *src = src_buf; > + unsigned int *dst = dst_buf; > + > + for (i = 0; i < len; i += 4, src++, dst++) > + swab32s(src); This will probably benefit from being unrolled slightly. Neither 'dst' nor the return value is used. > + > + return dst_buf; > +} > + > static void fec_dump(struct net_device *ndev) > { > struct fec_enet_private *fep = netdev_priv(ndev); > @@ -1334,7 +1346,7 @@ fec_enet_new_rxbdp(struct net_device *ndev, struct bufdesc *bdp, struct sk_buff > } > > static bool fec_enet_copybreak(struct net_device *ndev, struct sk_buff **skb, > - struct bufdesc *bdp, u32 length) > + struct bufdesc *bdp, u32 length, bool swap) > { > struct fec_enet_private *fep = netdev_priv(ndev); > struct sk_buff *new_skb; > @@ -1349,7 +1361,10 @@ static bool fec_enet_copybreak(struct net_device *ndev, struct sk_buff **skb, > dma_sync_single_for_cpu(&fep->pdev->dev, bdp->cbd_bufaddr, > FEC_ENET_RX_FRSIZE - fep->rx_align, > DMA_FROM_DEVICE); > - memcpy(new_skb->data, (*skb)->data, length); > + if (!swap) > + memcpy(new_skb->data, (*skb)->data, length); > + else > + swap_buffer2(new_skb->data, (*skb)->data, length); > *skb = new_skb; > > return true; > @@ -1377,6 +1392,7 @@ fec_enet_rx_queue(struct net_device *ndev, int budget, u16 queue_id) > u16 vlan_tag; > int index = 0; > bool is_copybreak; > + bool need_swap = fep->quirks & FEC_QUIRK_SWAP_FRAME; > > #ifdef CONFIG_M532x > flush_cache_all(); > @@ -1440,7 +1456,8 @@ fec_enet_rx_queue(struct net_device *ndev, int budget, u16 queue_id) > * include that when passing upstream as it messes up > * bridging applications. > */ > - is_copybreak = fec_enet_copybreak(ndev, &skb, bdp, pkt_len - 4); > + is_copybreak = fec_enet_copybreak(ndev, &skb, bdp, pkt_len - 4, > + need_swap); > if (!is_copybreak) { > skb_new = netdev_alloc_skb(ndev, FEC_ENET_RX_FRSIZE); > if (unlikely(!skb_new)) { > @@ -1455,7 +1472,7 @@ fec_enet_rx_queue(struct net_device *ndev, int budget, u16 queue_id) > prefetch(skb->data - NET_IP_ALIGN); > skb_put(skb, pkt_len - 4); > data = skb->data; > - if (fep->quirks & FEC_QUIRK_SWAP_FRAME) > + if (!is_copybreak && need_swap) > swap_buffer(data, pkt_len); It has to be better to set the 'copybreak' limit to be larger than the maximum frame size and so always go through the 'copybreak' paths. > > /* Extract the enhanced buffer descriptor */ > -- > 1.7.10.4 > > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html ????{.n?+???????+%?????ݶ??w??{.n?+????{??G?????{ay?ʇڙ?,j??f???h?????????z_??(?階?ݢj"???m??????G????????????&???~???iO???z??v?^?m???? ????????I?