From patchwork Wed Apr 27 11:51:50 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Liu Jian X-Patchwork-Id: 12828699 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7889AC433EF for ; Wed, 27 Apr 2022 11:50:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233119AbiD0Lxd (ORCPT ); Wed, 27 Apr 2022 07:53:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51320 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233100AbiD0Lxd (ORCPT ); Wed, 27 Apr 2022 07:53:33 -0400 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B74DE13BBCC; Wed, 27 Apr 2022 04:50:21 -0700 (PDT) Received: from canpemm500010.china.huawei.com (unknown [172.30.72.55]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4KpH4q0CkhzCrmM; Wed, 27 Apr 2022 19:45:47 +0800 (CST) Received: from huawei.com (10.175.101.6) by canpemm500010.china.huawei.com (7.192.105.118) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Wed, 27 Apr 2022 19:50:19 +0800 From: Liu Jian To: , , , , , , , , , , , , , CC: Subject: [PATCH bpf-next] bpf, sockmap: Call skb_linearize only when required in sk_psock_skb_ingress_enqueue Date: Wed, 27 Apr 2022 19:51:50 +0800 Message-ID: <20220427115150.210213-1-liujian56@huawei.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 X-Originating-IP: [10.175.101.6] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To canpemm500010.china.huawei.com (7.192.105.118) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net The skb_to_sgvec fails only when the number of frag_list and frags exceeds MAX_MSG_FRAGS. Therefore, we can call skb_linearize only when the conversion fails. Signed-off-by: Liu Jian Acked-by: John Fastabend --- net/core/skmsg.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-) diff --git a/net/core/skmsg.c b/net/core/skmsg.c index cc381165ea08..22b983ade0e7 100644 --- a/net/core/skmsg.c +++ b/net/core/skmsg.c @@ -524,16 +524,20 @@ static int sk_psock_skb_ingress_enqueue(struct sk_buff *skb, { int num_sge, copied; - /* skb linearize may fail with ENOMEM, but lets simply try again - * later if this happens. Under memory pressure we don't want to - * drop the skb. We need to linearize the skb so that the mapping - * in skb_to_sgvec can not error. - */ - if (skb_linearize(skb)) - return -EAGAIN; num_sge = skb_to_sgvec(skb, msg->sg.data, off, len); - if (unlikely(num_sge < 0)) - return num_sge; + if (num_sge < 0) { + /* skb linearize may fail with ENOMEM, but lets simply try again + * later if this happens. Under memory pressure we don't want to + * drop the skb. We need to linearize the skb so that the mapping + * in skb_to_sgvec can not error. + */ + if (skb_linearize(skb)) + return -EAGAIN; + + num_sge = skb_to_sgvec(skb, msg->sg.data, off, len); + if (unlikely(num_sge < 0)) + return num_sge; + } copied = len; msg->sg.start = 0;