From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=74.125.228.8 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793327588; b=sr/tUZX4DMuNegvxlLrK6qCx1aK5r/w8lOflHbm6cW0hvZ8BFaTMrWs62J+3oy7VeW+K IqZLoRt5SBIAU+eJAD6DleJY6pgh5+I9ZNSfMrDwIYI4v7yQjWBI4WglN6Nfxn+Pcs50F s7RIFR8hDtFJchp7sLQLYlHJFxq1JuitD9yMtdng47U0rCVDxlnJboNPg+1dpSbH9M3Hd Y4xu4xrsYp9GHzGV+mFX2+E213EV/OBTHxx+srsjC/iQ9ouWy5BYNVGpmtEiK8E0LBYrI gIsWy8TKFdimrtlkLcU88w4zjaQ/a1woOrEUeLLLAvhk0ma4Km/THJiTZnQHZCKlZ+Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793327588; h=DMARC-Filter:Received:DKIM-Signature:X-Google-DKIM-Signature: X-Forwarded-Encrypted:X-Gm-Message-State:X-Gm-Gg:X-Received:Received: From:To:Cc:Subject:Date:Message-Id:X-Mailer:In-Reply-To:References: MIME-Version:Content-Transfer-Encoding; bh=SIKkfA67UvQRqidJv7Hfli6cr7/y7nUfM2Bx1BgiLkE=; b=orOViOT9dU/wNINf19LGY7AhAdXudGK5QZazb/FRCwLcaGFonpmnwcjCbMMvTuH9Thbo 6LkHu2DzZKhqAZEsw61xk7L/Dq97FTBXfWfy5njdC5OQ61Szeo5hcQWvvVoFYt55VKglA 6NoG0YNFhcl1l58ENO14lnF1vQKMppd7RxrsjoyZdnga0DpoxzBNFJXCqXBW92XXEGwPB 4FsD8pERm9S1MNmMpmmQ/ofmmFM9ft/odFPeekdndzTSeWnCYHqWUAnSZKebTCxOu12uK tK1jrchltk9UTGGHwhXV7lzue/GJmlBxTVJP7qyaK75+kt09iuE2EhArP3iS1fcw9YA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20260707 header.b=QyXdKLmK; arc=none smtp.remote-ip=74.125.228.8 Received: from mail-pz2-f8.google.com (mail-pz2-f8.google.com [74.125.228.8]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C7157606A324 for ; Fri, 30 Oct 2026 02:33:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org C7157606A324 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20260707 header.b=QyXdKLmK Received: by mail-pz2-f8.google.com with SMTP id 41be03b00d2f7-cd1da63bff6so2622a12.0 for ; Thu, 29 Oct 2026 19:33:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20260707; t=1793327587; x=1793932387; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=SIKkfA67UvQRqidJv7Hfli6cr7/y7nUfM2Bx1BgiLkE=; b=QyXdKLmKaR0WHK0cJTyFaUEpfibyyQ5fW3kfeppI+vJOMhX/FDqjeS5UvEkcfOh/Uo 1Wshvu8W9MHdPi+8huvuLQyvCeClepU067PEo9L6qJSpL3CLideAGORYNP+htWkiex35 cuuJAzAs60zHbt9J/E0/3obXUk5lF8JFwiBzv/wsVpJ1WGdxrVyuTWIJjTIDNVs2eKAo x8+ehuhDeYWrDvVihQjj1onRG9tt+RHuw9H+aoVnYhPozwBhthzYcwLwFNEn889tbE78 qia9oIKxu6TAi7PmpnL4ocyoXPtmVJtBOpTsYLyaFb6R2iZyosdbH9WnJkpghCJWGGoc Mc9w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1793327587; x=1793932387; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=SIKkfA67UvQRqidJv7Hfli6cr7/y7nUfM2Bx1BgiLkE=; b=SoTSlg7DrLIw1s9T+V/7zhhfNTcFmOKMSPdw2eJLQnEqi9tmpBQMoZKwk1ro1mKhHZ X8vxeV5FmqeqUaLq8cHkoVxON9B9LVXCB9XoXgtY+n+GVuDsX60NIYKOihzcIMLgPuHe iBFsYWoepER16C8csMTaywu8ixbTcToqPMtCWpMDHMqhYlcLJiJpaSrbm8kYGJiJTDGZ 3eBC31ETPUK9R/6pUwYlaS+Gq8Lw9hj/PvMmLJWzXc8JLJuoWWc9zHsKuWpLCW8tJN2c 7tl2sRRlbkPQk0oTycXnnS5F23JzrKA6NhdbE5thbvyqhcRax0zQClSTaP8DhbOdVwOC oVTg== X-Forwarded-Encrypted: i=1; AKwUvBz3THnxeZQIhXLjm2lZD2mRrR7ePbw9bLJPeiRHIuwOkPZHk62Y1JBd+X8RUAAnr94WS7FAdvY=@vger.kernel.org X-Gm-Message-State: AFq9FYL/qkbJ3tZhO7pa6+/F+uCiJvNF5wtRjlBBUuBeB150S/4Nz6i3 CbRM4xZls3+Mc58uJUccI9Wa4DwPHgIUTu81xaOhH9NcoVtnc1dN9jHu X-Gm-Gg: AYBFou1g4f1Jpnvi7BYV9GpyXmEaSjRnlSw7KjNGnVsbbT/nUGz5H/zgJPQui7fBzGz Uae5DIBM3B9a3JwXLqEyu7T1ZB9AFvV3Al3cMqA3i4yXeKc61dRiiI1iAVrNQtoPtXpuwme+Fxl OrDmYNTUVKKMAomJSO7gzzJd4x70Kx0due9ge3pIcy7QSo3WbKXpOTyhbcbWMR+iV0WiQOrzluO qq6CgqkC2TGqa//MXhj9c83yWgumBpUJex+VeODUJCLvt1jSkJLkcMVy74acIHfbNoBaIIcHdDQ NYk68QTi5eKqQ/hja3leNIk9W1lbasmuoBJbpyzKFO6z+P2wBbLNUHe9B5Gu3kj3DNxGgPqGq+W /YZ8zqjy4OUJqmzfwGdbWiyV4DQRKOHt8XO84gmvA85N71JE1rsQwgILyILmaIjAK3GaRkOFG4P Qlvp5fz8k05f2WSJv/8Z3ucoYk5kDs2qiqo/jHe543uR7pekITbYvauDzEEEVmSzcRphN2OTFCo 3FTDJioqAhxuEk/8fHsIKQUnqoTPXimJSsCrQESjmMd7b8MRz+SJjenDrHlw1K+2tOGcNYvu4Mw ZstXpU5veqRqM1MeiWslZGkmxyXUmQXjlf0CTYGd6fKthelJI+iKceY= X-Received: by 2002:a05:6a00:a256:b0:882:2195:5a73 with SMTP id d2e1a72fcca58-8a9bfde0494mr516804b3a.29.1793327587137; Thu, 29 Oct 2026 19:33:07 -0700 (PDT) Received: from localhost.localdomain ([58.247.233.220]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-8a9eef95f2dsm152216b3a.10.2026.10.29.19.33.00 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Thu, 29 Oct 2026 19:33:06 -0700 (PDT) From: Rongzheng Wang To: netdev@vger.kernel.org Cc: Maciej Fijalkowski , Magnus Karlsson , Jason Xing , Stanislav Fomichev , Jesper Dangaard Brouer , stable@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, Rongzheng Wang Subject: [PATCH net v4 1/2] xsk: defer software checksum until the skb is complete Date: Fri, 30 Oct 2026 10:32:47 +0800 Message-Id: <20261030023248.78802-2-testwrzwrz@gmail.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) In-Reply-To: <20261030023248.78802-1-testwrzwrz@gmail.com> References: <20261030023248.78802-1-testwrzwrz@gmail.com> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When XDP_UMEM_TX_SW_CSUM is used with multi-buffer TX, xsk_skb_metadata() calls skb_checksum_help() while only the first descriptor has been added to the skb. The checksum therefore covers just the first fragment, and skb_checksum_help() sets ip_summed to CHECKSUM_NONE, so the remaining fragments are never included in the checksum. Move the software checksum calculation to the point where the last descriptor has been added to the skb. On a checksum failure the packet is now dropped instead of being returned to the application for a retry. This path is not reachable with the existing metadata validation, but the behavior change is intentional. Fixes: 11614723af26 ("xsk: Add option to calculate TX checksum in SW") Cc: stable@vger.kernel.org Signed-off-by: Rongzheng Wang --- net/xdp/xsk.c | 23 +++++++++++++++-------- 1 file changed, 15 insertions(+), 8 deletions(-) diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index 33475b180ea6..aa6b010192ad 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -1011,14 +1011,6 @@ static int xsk_skb_metadata(struct sk_buff *skb, void *buffer, skb->csum_start = hr + csum_start; skb->csum_offset = csum_offset; skb->ip_summed = CHECKSUM_PARTIAL; - - if (unlikely(pool->tx_sw_csum)) { - int err; - - err = skb_checksum_help(skb); - if (err) - return err; - } } if (flags & XDP_TXMD_FLAGS_LAUNCH_TIME) @@ -1030,6 +1022,15 @@ static int xsk_skb_metadata(struct sk_buff *skb, void *buffer, return 0; } +static int xsk_skb_sw_csum(struct sk_buff *skb, struct xsk_buff_pool *pool) +{ + if (unlikely(pool->tx_sw_csum && + skb->ip_summed == CHECKSUM_PARTIAL)) + return skb_checksum_help(skb); + + return 0; +} + static struct sk_buff *xsk_build_skb_zerocopy(struct xdp_sock *xs, struct xdp_desc *desc) { @@ -1275,6 +1276,12 @@ static int __xsk_generic_xmit(struct sock *sk) if (xp_mb_desc(&desc)) { xs->skb = skb; continue; + } else { + err = xsk_skb_sw_csum(skb, xs->pool); + if (unlikely(err)) { + xsk_drop_skb(skb); + goto out; + } } err = __dev_direct_xmit(skb, xs->queue_id); -- 2.39.5 (Apple Git-154)