From patchwork Fri Nov 27 17:38:49 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Simon Wunderlich X-Patchwork-Id: 11936961 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5ADE4C63798 for ; Fri, 27 Nov 2020 17:39:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1E72822201 for ; Fri, 27 Nov 2020 17:39:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732345AbgK0RjB (ORCPT ); Fri, 27 Nov 2020 12:39:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34764 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732209AbgK0RjB (ORCPT ); Fri, 27 Nov 2020 12:39:01 -0500 Received: from simonwunderlich.de (packetmixer.de [IPv6:2001:4d88:2000:24::c0de]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A9974C0617A7 for ; Fri, 27 Nov 2020 09:39:00 -0800 (PST) Received: from kero.packetmixer.de (p200300c59712a4e04204e2f79fd8c031.dip0.t-ipconnect.de [IPv6:2003:c5:9712:a4e0:4204:e2f7:9fd8:c031]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by simonwunderlich.de (Postfix) with ESMTPSA id 30C37174062; Fri, 27 Nov 2020 18:38:59 +0100 (CET) From: Simon Wunderlich To: davem@davemloft.net, kuba@kernel.org Cc: netdev@vger.kernel.org, b.a.t.m.a.n@lists.open-mesh.org, Sven Eckelmann , Simon Wunderlich Subject: [PATCH 3/3] batman-adv: Don't always reallocate the fragmentation skb head Date: Fri, 27 Nov 2020 18:38:49 +0100 Message-Id: <20201127173849.19208-4-sw@simonwunderlich.de> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20201127173849.19208-1-sw@simonwunderlich.de> References: <20201127173849.19208-1-sw@simonwunderlich.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org From: Sven Eckelmann When a packet is fragmented by batman-adv, the original batman-adv header is not modified. Only a new fragmentation is inserted between the original one and the ethernet header. The code must therefore make sure that it has a writable region of this size in the skbuff head. But it is not useful to always reallocate the skbuff by this size even when there would be more than enough headroom still in the skb. The reallocation is just to costly during in this codepath. Fixes: ee75ed88879a ("batman-adv: Fragment and send skbs larger than mtu") Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich --- net/batman-adv/fragmentation.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/net/batman-adv/fragmentation.c b/net/batman-adv/fragmentation.c index 8de1fb567fd7..1f1f5b0873b2 100644 --- a/net/batman-adv/fragmentation.c +++ b/net/batman-adv/fragmentation.c @@ -527,13 +527,14 @@ int batadv_frag_send_packet(struct sk_buff *skb, frag_header.no++; } - /* Make room for the fragment header. */ - if (batadv_skb_head_push(skb, header_size) < 0 || - pskb_expand_head(skb, header_size + ETH_HLEN, 0, GFP_ATOMIC) < 0) { - ret = -ENOMEM; + /* make sure that there is at least enough head for the fragmentation + * and ethernet headers + */ + ret = skb_cow_head(skb, ETH_HLEN + header_size); + if (ret < 0) goto put_primary_if; - } + skb_push(skb, header_size); memcpy(skb->data, &frag_header, header_size); /* Send the last fragment */