From patchwork Thu Aug 24 19:26:54 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Larysa Zaremba X-Patchwork-Id: 13364611 X-Patchwork-Delegate: bpf@iogearbox.net Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9D6851E506; Thu, 24 Aug 2023 19:34:27 +0000 (UTC) Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A2F501B0; Thu, 24 Aug 2023 12:34:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1692905666; x=1724441666; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=5p/6LrkVhD1srZ1C0shnBPSltvtTeK9faThdhrldm0U=; b=ABrFOlPFBsrWUqU1217NM390Lp8oONkyGtoPX+AqR48XFW36oEXB8f3w 3qb+I8YLTaamjsJkX637WfpqNI0/3tA59CNCVtlfVw2I4FzO1EUq5L1gh TPV59vIUoAPcWxixRykh3lBAHs2dBdoiau40Wj0LvashPXF62HF8bSVFP 6U2nds7Y1ExiA8WfPYuvcYSTvMHSugjir3oI3CjWTh87wqJnb77fRUIZj HiZCZlKVejHWgyuh6VTv6zeg5JDrLjaWgIg69Dse3yiEZThJj7J/FCyAw Gc4Gz5R7uZSkf/1Tr499fuVl1bkmlUnr7oeqh/+GJCj044Y+hcBq36pT+ g==; X-IronPort-AV: E=McAfee;i="6600,9927,10812"; a="354865386" X-IronPort-AV: E=Sophos;i="6.02,195,1688454000"; d="scan'208";a="354865386" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Aug 2023 12:34:26 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10812"; a="860830553" X-IronPort-AV: E=Sophos;i="6.02,195,1688454000"; d="scan'208";a="860830553" Received: from irvmail002.ir.intel.com ([10.43.11.120]) by orsmga004.jf.intel.com with ESMTP; 24 Aug 2023 12:34:19 -0700 Received: from lincoln.igk.intel.com (lincoln.igk.intel.com [10.102.21.235]) by irvmail002.ir.intel.com (Postfix) with ESMTP id C38A133EA3; Thu, 24 Aug 2023 20:34:17 +0100 (IST) From: Larysa Zaremba To: bpf@vger.kernel.org Cc: Larysa Zaremba , ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, David Ahern , Jakub Kicinski , Willem de Bruijn , Jesper Dangaard Brouer , Anatoly Burakov , Alexander Lobakin , Magnus Karlsson , Maryam Tahhan , xdp-hints@xdp-project.net, netdev@vger.kernel.org, Willem de Bruijn , Alexei Starovoitov , Simon Horman , Tariq Toukan , Saeed Mahameed , Aleksander Lobakin Subject: [RFC bpf-next 15/23] net, xdp: allow metadata > 32 Date: Thu, 24 Aug 2023 21:26:54 +0200 Message-ID: <20230824192703.712881-16-larysa.zaremba@intel.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230824192703.712881-1-larysa.zaremba@intel.com> References: <20230824192703.712881-1-larysa.zaremba@intel.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: bpf@iogearbox.net X-Patchwork-State: RFC From: Aleksander Lobakin When using XDP hints, metadata sometimes has to be much bigger than 32 bytes. Relax the restriction, allow metadata larger than 32 bytes and make __skb_metadata_differs() work with bigger lengths. Now size of metadata is only limited by the fact it is stored as u8 in skb_shared_info, so maximum possible value is 255. Other important conditions, such as having enough space for xdp_frame building, are already checked in bpf_xdp_adjust_meta(). The requirement of having its length aligned to 4 bytes is still valid. Signed-off-by: Aleksander Lobakin Signed-off-by: Larysa Zaremba --- include/linux/skbuff.h | 13 ++++++++----- include/net/xdp.h | 7 ++++++- 2 files changed, 14 insertions(+), 6 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index aa57e2eca33b..0e455678cb8a 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -4216,10 +4216,13 @@ static inline bool __skb_metadata_differs(const struct sk_buff *skb_a, { const void *a = skb_metadata_end(skb_a); const void *b = skb_metadata_end(skb_b); - /* Using more efficient varaiant than plain call to memcmp(). */ -#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64 u64 diffs = 0; + if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) || + BITS_PER_LONG != 64) + goto slow; + + /* Using more efficient variant than plain call to memcmp(). */ switch (meta_len) { #define __it(x, op) (x -= sizeof(u##op)) #define __it_diff(a, b, op) (*(u##op *)__it(a, op)) ^ (*(u##op *)__it(b, op)) @@ -4239,11 +4242,11 @@ static inline bool __skb_metadata_differs(const struct sk_buff *skb_a, fallthrough; case 4: diffs |= __it_diff(a, b, 32); break; + default: +slow: + return memcmp(a - meta_len, b - meta_len, meta_len); } return diffs; -#else - return memcmp(a - meta_len, b - meta_len, meta_len); -#endif } static inline bool skb_metadata_differs(const struct sk_buff *skb_a, diff --git a/include/net/xdp.h b/include/net/xdp.h index 495c4d2a2c50..05234f156a73 100644 --- a/include/net/xdp.h +++ b/include/net/xdp.h @@ -369,7 +369,12 @@ xdp_data_meta_unsupported(const struct xdp_buff *xdp) static inline bool xdp_metalen_invalid(unsigned long metalen) { - return (metalen & (sizeof(__u32) - 1)) || (metalen > 32); + typeof(metalen) meta_max; + + meta_max = type_max(typeof_member(struct skb_shared_info, meta_len)); + BUILD_BUG_ON(!__builtin_constant_p(meta_max)); + + return !IS_ALIGNED(metalen, sizeof(u32)) || metalen > meta_max; } struct xdp_attachment_info {