From patchwork Sat Nov 20 12:40:53 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sven Eckelmann X-Patchwork-Id: 18432 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 AB169844A6; Sat, 20 Nov 2021 13:41:05 +0100 (CET) Received: from dvalin.narfation.org (dvalin.narfation.org [213.160.73.56]) by diktynna.open-mesh.org (Postfix) with ESMTPS id 4316B8448E for ; Sat, 20 Nov 2021 13:41:02 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=narfation.org; s=20121; t=1637412062; 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=Doh3R1ILM4ebcu1GsGngu/p/+ecj2NCrShmGAQilqss=; b=RgvGaXDhsdoWuPJC2CQ/l3vDf3/hdY85i/sfFpdt7/ru9591FAE4OQkfumEbWjs19PKgdU cNuUkapSVsHR/+KSbMdRz7MdUsnDj8eEtkLsIu06179MKxgbU0iZOAj0Yh6UdfkU9nnzpd hLCV8kfH4FUJ8Sk+9ex8sD0YA9zZGJk= From: Sven Eckelmann To: stable@vger.kernel.org Subject: [PATCH 5.4 3/3] batman-adv: Don't always reallocate the fragmentation skb head Date: Sat, 20 Nov 2021 13:40:53 +0100 Message-Id: <20211120124053.261156-4-sven@narfation.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211120124053.261156-1-sven@narfation.org> References: <20211120124053.261156-1-sven@narfation.org> MIME-Version: 1.0 ARC-Seal: i=1; s=20121; d=open-mesh.org; t=1637412062; a=rsa-sha256; cv=none; b=QDsOEYBMZUrCMv08OaqXsVB64licJXl/hySK3R/PBd5xy4mSxvrPwRZbmWwkc2SUSNf8vQ 3xOpmwFcBMZwGRuA6gL65IAvuCbxVjmjZX2yzV6ehFcZrfHg7OINhMvaFUARry2IIbhU8+ J67oQKq3VNVkHP3jh8Dv79gg1wAp+fs= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=open-mesh.org; s=20121; t=1637412062; 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=Doh3R1ILM4ebcu1GsGngu/p/+ecj2NCrShmGAQilqss=; b=JBoYvZ2Ff3pJmgRvfXtQF1ZW/A0vUBu1wBWBDeIP3+dOV4XVQOm9iO1XwnfuwQ4pua6RX/ AMWKoIv5rsZ56qUgAFfW3ajcgMW5k3JP29owaqERatzb2eiSuWzUoDzmT4dObLGjg4NLZr jPSWR10ueEWIbYI1UeVwAeECRKdUPFo= ARC-Authentication-Results: i=1; diktynna.open-mesh.org; dkim=pass header.d=narfation.org header.s=20121 header.b=RgvGaXDh; 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: NZOWUC4USLGVJ6ZYN7KXFPCBOOAX5UVY X-Message-ID-Hash: NZOWUC4USLGVJ6ZYN7KXFPCBOOAX5UVY 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 Signed-off-by: Sven Eckelmann --- 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 f1d202ff396c..0da90e73c79b 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 */