From patchwork Mon Nov 7 18:54:50 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Felix Fietkau X-Patchwork-Id: 13035160 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E9610C43219 for ; Mon, 7 Nov 2022 19:26:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=C98usNxyr+U7FAXP/mV5Y5yH3ZAveUntszdeGTfZarg=; b=BZbqbYD93BsIZt bnNVD6kXzRsjA3DglUuQCrxNUyQAwZB5qO52DyvSrXQ3cYPu8s0AQSAHZXGmkCwKP7NWLWcWNb2mK YOxOCCAGiMh9HLkgciM91MGyXIwJHebqCDezSxf1XunFm8qJOspkAE2iaBM8issP8vUYfwDdQOMmD iydzy2efbMv7ZJXnX/6/btizIhsbuXL1uYGHwwovWyyo6inld6ukJZYTKO7p0WkxYDDnQVaIkbdmT rcXXnH3R4yyhva/1ochSJqxWmuQdf4wIqW0LjF5M5qsKNRgjcHdIMYQ9glo/tQUYX7Z7W75pcjREP 9r3QQvVFs55dWjDonG7g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1os7kR-00Haki-Vl; Mon, 07 Nov 2022 19:25:32 +0000 Received: from nbd.name ([46.4.11.11]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1os7kP-00Hajj-Mc; Mon, 07 Nov 2022 19:25:30 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=nbd.name; s=20160729; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=xCr45UuzrLNIeKdnQROVOgewNl0be/E8YvRAW/QU3O4=; b=A8NmC8uyAFNHwtnVUx1Qg7EzE/ Iia6sjNBFsbKq34UUC19vohNFhU7am+FpMSYWIA2OfmGK66c8ECVwH3nHo4ppZcr3N+ba2bZ/xYyq Kzj6VV21d+Q/KQj0xs2PNzZ3IJisJNXILxTddQSNTUcLc6OV49Ngjqdg0WSQSvWpBiJQ=; Received: from p200300daa72ee1007849d74f78949f6c.dip0.t-ipconnect.de ([2003:da:a72e:e100:7849:d74f:7894:9f6c] helo=Maecks.lan) by ds12 with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 (Exim 4.94.2) (envelope-from ) id 1os7HH-000LCc-5a; Mon, 07 Nov 2022 19:55:23 +0100 From: Felix Fietkau To: netdev@vger.kernel.org, John Crispin , Sean Wang , Mark Lee , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Matthias Brugger Cc: linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH 12/14] net: ethernet: mtk_eth_soc: work around issue with sending small fragments Date: Mon, 7 Nov 2022 19:54:50 +0100 Message-Id: <20221107185452.90711-12-nbd@nbd.name> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221107185452.90711-1-nbd@nbd.name> References: <20221107185452.90711-1-nbd@nbd.name> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221107_112529_754262_100CF333 X-CRM114-Status: GOOD ( 14.97 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org When frames are sent with very small fragments, the DMA engine appears to lock up and transmit attempts time out. Fix this by detecting the presence of small fragments and use skb_gso_segment + skb_linearize to deal with them Signed-off-by: Felix Fietkau --- drivers/net/ethernet/mediatek/mtk_eth_soc.c | 36 +++++++++++++++++++-- 1 file changed, 34 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c index 3b8995a483aa..50756c8aa871 100644 --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c @@ -1441,12 +1441,28 @@ static void mtk_wake_queue(struct mtk_eth *eth) } } +static bool mtk_skb_has_small_frag(struct sk_buff *skb) +{ + int min_size = 16; + int i; + + if (skb_headlen(skb) < min_size) + return true; + + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) + if (skb_frag_size(&skb_shinfo(skb)->frags[i]) < min_size) + return true; + + return false; +} + static netdev_tx_t mtk_start_xmit(struct sk_buff *skb, struct net_device *dev) { struct mtk_mac *mac = netdev_priv(dev); struct mtk_eth *eth = mac->hw; struct mtk_tx_ring *ring = ð->tx_ring; struct net_device_stats *stats = &dev->stats; + struct sk_buff *segs, *next; bool gso = false; int tx_num; @@ -1468,6 +1484,17 @@ static netdev_tx_t mtk_start_xmit(struct sk_buff *skb, struct net_device *dev) return NETDEV_TX_BUSY; } + if (skb_is_gso(skb) && mtk_skb_has_small_frag(skb)) { + segs = skb_gso_segment(skb, dev->features & ~NETIF_F_ALL_TSO); + if (IS_ERR(segs)) + goto drop; + + if (segs) { + consume_skb(skb); + skb = segs; + } + } + /* TSO: fill MSS info in tcp checksum field */ if (skb_is_gso(skb)) { if (skb_cow_head(skb, 0)) { @@ -1483,8 +1510,13 @@ static netdev_tx_t mtk_start_xmit(struct sk_buff *skb, struct net_device *dev) } } - if (mtk_tx_map(skb, dev, tx_num, ring, gso) < 0) - goto drop; + skb_list_walk_safe(skb, skb, next) { + if ((mtk_skb_has_small_frag(skb) && skb_linearize(skb)) || + mtk_tx_map(skb, dev, tx_num, ring, gso) < 0) { + stats->tx_dropped++; + dev_kfree_skb_any(skb); + } + } if (unlikely(atomic_read(&ring->free_count) <= ring->thresh)) netif_tx_stop_all_queues(dev);