From patchwork Sat Dec 16 19:36:52 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Linus Walleij X-Patchwork-Id: 13495718 X-Patchwork-Delegate: kuba@kernel.org Received: from mail-lf1-f49.google.com (mail-lf1-f49.google.com [209.85.167.49]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8B90F31A8E for ; Sat, 16 Dec 2023 19:36:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linaro.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linaro.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="AwkAdIVr" Received: by mail-lf1-f49.google.com with SMTP id 2adb3069b0e04-50e30b28c1aso299782e87.0 for ; Sat, 16 Dec 2023 11:36:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1702755413; x=1703360213; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=RVRwOGlgS4OX+8vqS+0hxHNi+4vVCWuPIOJJBMqWhWs=; b=AwkAdIVrpZzQjk1itmEtvQHQXik0zUpSni1rLSkQsNifH6+QEUgePUKjtPfMSJGs37 apjy0Elf6ydjs4IG0sqkDaaT6LhjE0XQtRGpZSDSxCfG5/elNhA8USwN3AXVyH5kLX7c EE+98jKl1e91p7DesMhOevmbBxtgJYOBuGRlwqf2BVSHn/Ljpv1pe6zOsYcB56zzHzOM ghCkWfzHs6/O0dUHpUFx4TKXcI7ZA0+uFEsL7KjiFNjBLav7GnKc0Uzh2kTKuNTGEjTq HJMnuJ2P9IwogX2fwjm2S2FzJf06XcX9CScw0G99NqCYGGt20UryT9fUkpnCWhhPCPtt pB6A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702755413; x=1703360213; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=RVRwOGlgS4OX+8vqS+0hxHNi+4vVCWuPIOJJBMqWhWs=; b=nIhIc4PXgGpw41q68WEpm6S6mH4NW0L3poQk8EIzS8oe93sZIvnL2GqZVq6sN1V/AP UGPikrKi1KUF9KniF1g473O7+po8sJoazBOIn3G+Q+bTTjT1nwb7hMHX7SdDJ9dK7WtV /eoW7m2UPEOtMoAs7u2/XA6y/xvowzF7lZTNnFQwtGFSh8JcY73a4TT+0YhizBxtFe5T tpLmQmXgyS8fS8KP60tCtGHj95ZFfRtwPcBn7SIbRGPbT9EQePAC/+0JcYuML4X02Wvj alWAeM7FJsCkMhuxiAaltjwbPhuNrebXYeeX1PDDFBMw8ciLE5EhCLcIsrJQfuoHJjBK qc6g== X-Gm-Message-State: AOJu0YxJHATxnLWI5rgIn/wYaja5xX6GVE9e6u4E3SQpUR754Yk1rkgD tRE4jUKBKMKCyVwbpWyLLh0cCs8RSh9QY0HgZ48= X-Google-Smtp-Source: AGHT+IHY2ROHEnoFTZYPwJOrMyDhsKSiT8c8G0JCi/UQNfM0wO3Ieumfb25ZUVURB0//wh+mxHCHxQ== X-Received: by 2002:ac2:4c4a:0:b0:50b:ef70:8d66 with SMTP id o10-20020ac24c4a000000b0050bef708d66mr8871731lfk.26.1702755413706; Sat, 16 Dec 2023 11:36:53 -0800 (PST) Received: from [127.0.1.1] ([85.235.12.238]) by smtp.gmail.com with ESMTPSA id u13-20020ac25bcd000000b0050bc96f5258sm2441553lfn.214.2023.12.16.11.36.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 16 Dec 2023 11:36:53 -0800 (PST) From: Linus Walleij Date: Sat, 16 Dec 2023 20:36:52 +0100 Subject: [PATCH net v2 1/2] net: ethernet: cortina: Drop software checksum and TSO Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20231216-new-gemini-ethernet-regression-v2-1-64c269413dfa@linaro.org> References: <20231216-new-gemini-ethernet-regression-v2-0-64c269413dfa@linaro.org> In-Reply-To: <20231216-new-gemini-ethernet-regression-v2-0-64c269413dfa@linaro.org> To: Hans Ulli Kroll , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: netdev@vger.kernel.org, Linus Walleij X-Mailer: b4 0.12.4 X-Patchwork-Delegate: kuba@kernel.org The recent change to allow large frames without hardware checksumming slotted in software checksumming in the driver if hardware could not do it. This will however upset TSO (TCP Segment Offloading). Typical error dumps includes this: skb len=2961 headroom=222 headlen=66 tailroom=0 (...) WARNING: CPU: 0 PID: 956 at net/core/dev.c:3259 skb_warn_bad_offload+0x7c/0x108 gemini-ethernet-port: caps=(0x0000010000154813, 0x00002007ffdd7889) And the packets do not go through. After investigating I drilled it down to the introduction of the software checksumming in the driver. Since the segmenting of packets will be done by the hardware this makes a bit of sense since in that case the hardware also needs to be keeping track of the checksumming. That begs the question why large TCP or UDP packets also have to bypass the checksumming (like e.g. ICMP does). If the hardware is splitting it into smaller packets per-MTU setting, and checksumming them, why is this happening then? I don't know. I know it is needed, from tests: the OpenWrt webserver uhttpd starts sending big skb:s (up to 2047 bytes, the max MTU) and above 1514 bytes it starts to fail and hang unless the bypass bit is set: the frames are not getting through. Drop the size check and the offloading features for now: this needs to be fixed up properly. Suggested-by: Eric Dumazet Fixes: d4d0c5b4d279 ("net: ethernet: cortina: Handle large frames") Signed-off-by: Linus Walleij --- drivers/net/ethernet/cortina/gemini.c | 21 ++------------------- 1 file changed, 2 insertions(+), 19 deletions(-) diff --git a/drivers/net/ethernet/cortina/gemini.c b/drivers/net/ethernet/cortina/gemini.c index 78287cfcbf63..6a7ea051391a 100644 --- a/drivers/net/ethernet/cortina/gemini.c +++ b/drivers/net/ethernet/cortina/gemini.c @@ -79,8 +79,7 @@ MODULE_PARM_DESC(debug, "Debug level (0=none,...,16=all)"); #define GMAC0_IRQ4_8 (GMAC0_MIB_INT_BIT | GMAC0_RX_OVERRUN_INT_BIT) #define GMAC_OFFLOAD_FEATURES (NETIF_F_SG | NETIF_F_IP_CSUM | \ - NETIF_F_IPV6_CSUM | NETIF_F_RXCSUM | \ - NETIF_F_TSO | NETIF_F_TSO_ECN | NETIF_F_TSO6) + NETIF_F_IPV6_CSUM | NETIF_F_RXCSUM ) /** * struct gmac_queue_page - page buffer per-page info @@ -1145,7 +1144,6 @@ static int gmac_map_tx_bufs(struct net_device *netdev, struct sk_buff *skb, dma_addr_t mapping; unsigned short mtu; void *buffer; - int ret; mtu = ETH_HLEN; mtu += netdev->mtu; @@ -1160,22 +1158,7 @@ static int gmac_map_tx_bufs(struct net_device *netdev, struct sk_buff *skb, word3 |= mtu; } - if (skb->len >= ETH_FRAME_LEN) { - /* Hardware offloaded checksumming isn't working on frames - * bigger than 1514 bytes. A hypothesis about this is that the - * checksum buffer is only 1518 bytes, so when the frames get - * bigger they get truncated, or the last few bytes get - * overwritten by the FCS. - * - * Just use software checksumming and bypass on bigger frames. - */ - if (skb->ip_summed == CHECKSUM_PARTIAL) { - ret = skb_checksum_help(skb); - if (ret) - return ret; - } - word1 |= TSS_BYPASS_BIT; - } else if (skb->ip_summed == CHECKSUM_PARTIAL) { + if (skb->ip_summed == CHECKSUM_PARTIAL) { int tcp = 0; /* We do not switch off the checksumming on non TCP/UDP