From patchwork Sat Nov 20 12:39:58 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sven Eckelmann X-Patchwork-Id: 18417 X-Patchwork-Delegate: sw@simonwunderlich.de Return-Path: X-Original-To: patchwork@open-mesh.org Delivered-To: patchwork@open-mesh.org Received: from diktynna.open-mesh.org (localhost [IPv6:::1]) by diktynna.open-mesh.org (Postfix) with ESMTP id 201BF83F1E; Sat, 20 Nov 2021 13:40:17 +0100 (CET) Received: from dvalin.narfation.org (dvalin.narfation.org [213.160.73.56]) by diktynna.open-mesh.org (Postfix) with ESMTPS id 6D49A83E98 for ; Sat, 20 Nov 2021 13:40:10 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=narfation.org; s=20121; t=1637412010; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=VjUYQ6oXZkBiXYjojTpahxcFcaCQNiZbys9b1nVcndc=; b=cdtu6n+fQKt4+gwYGFO2/TjRC967LMUtCL7Q2FznYKqE1pDqPO1KnYAgJTcFz5dMGLGVM1 RG+xCWPCVauHmZ5wtqzCPSrmt8i1ZltzNzoOIqsPwgA5bDVS3ydElyqJai4LaHelxFApxj BwK3AIkHvz5Ibo7l6Zd319u66L689Co= From: Sven Eckelmann To: stable@vger.kernel.org Subject: [PATCH 4.9 7/7] batman-adv: Don't always reallocate the fragmentation skb head Date: Sat, 20 Nov 2021 13:39:58 +0100 Message-Id: <20211120123958.260826-8-sven@narfation.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211120123958.260826-1-sven@narfation.org> References: <20211120123958.260826-1-sven@narfation.org> MIME-Version: 1.0 ARC-Seal: i=1; s=20121; d=open-mesh.org; t=1637412010; a=rsa-sha256; cv=none; b=uD33BWhjaALU7UZNQc87VgiMarwV0hyABlOHhdGkvkMAt0keUH0ZM3ajPRNZuZeaMr5H+/ qqThmKzH6pWzBWNJlgWnaLgdy939E5tTLFKNipQeJP8U4cbKwi7b9nOZEV3b8l/qR0Xf03 JzTQQgtqVPzuV0Ju+ItYKbvSQpSvXTE= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=open-mesh.org; s=20121; t=1637412010; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=VjUYQ6oXZkBiXYjojTpahxcFcaCQNiZbys9b1nVcndc=; b=cu4KYG/uKPYZzv5YM2M6y/bd/RSSwSSFnTv5zYjD1WDJFvCGpwHjtOnTIec5A/jzOj6IEw JC5EN3GJKpcmvovR9UMi0Tr/FFqgbIsFy9E34PTu2aRUB5O+42HDXiJni1Irz1/wXUHuip 856RKu5dCYzn/LsSs164/KMpAUMThkE= ARC-Authentication-Results: i=1; diktynna.open-mesh.org; dkim=pass header.d=narfation.org header.s=20121 header.b=cdtu6n+f; spf=pass (diktynna.open-mesh.org: domain of sven@narfation.org designates 213.160.73.56 as permitted sender) smtp.mailfrom=sven@narfation.org; dmarc=pass (policy=none) header.from=narfation.org Message-ID-Hash: 6WC7VCCQR6Z7E3NWRTQ7WD433SJDHEUU X-Message-ID-Hash: 6WC7VCCQR6Z7E3NWRTQ7WD433SJDHEUU X-MailFrom: sven@narfation.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-b.a.t.m.a.n.lists.open-mesh.org-0; header-match-b.a.t.m.a.n.lists.open-mesh.org-1; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; suspicious-header CC: b.a.t.m.a.n@lists.open-mesh.org X-Mailman-Version: 3.2.1 Precedence: list Reply-To: The list for a Better Approach To Mobile Ad-hoc Networking List-Id: The list for a Better Approach To Mobile Ad-hoc Networking Archived-At: List-Archive: List-Help: List-Post: List-Subscribe: List-Unsubscribe: commit 992b03b88e36254e26e9a4977ab948683e21bd9f upstream. 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 [ bp: 4.9 backported: adjust context. ] Signed-off-by: Sven Eckelmann --- net/batman-adv/fragmentation.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/net/batman-adv/fragmentation.c b/net/batman-adv/fragmentation.c index 353772eb4f4d..343f4fc5909d 100644 --- a/net/batman-adv/fragmentation.c +++ b/net/batman-adv/fragmentation.c @@ -528,11 +528,14 @@ 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) + /* 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 out; + skb_push(skb, header_size); memcpy(skb->data, &frag_header, header_size); /* Send the last fragment */