From patchwork Thu Nov 10 07:31:25 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuang Wang X-Patchwork-Id: 13038385 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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3DEDFC433FE for ; Thu, 10 Nov 2022 07:32:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232844AbiKJHbt (ORCPT ); Thu, 10 Nov 2022 02:31:49 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47902 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232448AbiKJHbn (ORCPT ); Thu, 10 Nov 2022 02:31:43 -0500 Received: from mail-pj1-x1035.google.com (mail-pj1-x1035.google.com [IPv6:2607:f8b0:4864:20::1035]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 00D35326D3; Wed, 9 Nov 2022 23:31:42 -0800 (PST) Received: by mail-pj1-x1035.google.com with SMTP id m6-20020a17090a5a4600b00212f8dffec9so924070pji.0; Wed, 09 Nov 2022 23:31:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=LbZXKKBD741m+fy6007yuueCSdvbrC+LAzehJa3fqi0=; b=FgzPsL8ax5mT2Bx8DVZYtSR68TPTIHcMPKgj5umNdVXzl9C9eOgrDvGpwbuYdcFmBZ +pcvufsen3b2SgWV7d9w6YAj3qLaH0gNN1itq57ioTny+RSl+Dz/Xv2L7RtjyIMfWwHC RJYZgroCvo6H7nob09QKqMwov02fM/yqnobI00nIyu+vJ/+jEE5nTqwAzGJ6Yiu+amdT 3lPCFfiqtcL5ZwcN+w6f4/CAy3wRYiiomgn+iZFNJKt+M8T5syYucOoeCQ+Ph56aac+6 i6BKSMzhwtTF96199xMWzgkcq8A5Oq3rLyFPrBLJkvp9QtuDTSaLF36lBRJqBFuRbcRe rgqQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=LbZXKKBD741m+fy6007yuueCSdvbrC+LAzehJa3fqi0=; b=zceDs8idgX+UhhJLTKpOWRyJD7Nm8DOjN0ZhCz0McWG9q4+d4zFTvJhITMEJcvV7DH /8Z9fnOddFSaFKyqjEshm/94aKDey4rzJB3OUzz8GF1/4xQSMIKswcE0tENbRRuIlB8C HCrl7J48hLjtAhUeI9lWUIfbLRM57tKzcAkTNj4qzjckeSVkMGF4GTOwgdl3XwyB3dRb PxGiLpfBfV+0aqvCglBJvTQJe6atlmIQ9AY7ufKkYqvxfH0oqYdou8L8/sJZ7GjCBEVN YO9IiokvwGVXk15xqHoh6io4zqrdFHs20npxSL2LvE6ndMy5047W3iWUmiDH066M6pOP eTxA== X-Gm-Message-State: ACrzQf0iDcz1khAk2TBWrJQkimFPhj5Hsgtg012R1QpE3Mze8IL/4vej NvI67tAAWzmzPBfdLSlGWYc= X-Google-Smtp-Source: AMsMyM6GNAP4EgSrMpzo2FjpKbIL1XTfylmWsdvmXcdLKjvpFx45AylRfUKfT/z+iOaYHtYLzw59mw== X-Received: by 2002:a17:90a:e7ce:b0:213:589b:cdaf with SMTP id kb14-20020a17090ae7ce00b00213589bcdafmr79963350pjb.186.1668065502331; Wed, 09 Nov 2022 23:31:42 -0800 (PST) Received: from localhost.localdomain ([47.242.114.172]) by smtp.gmail.com with ESMTPSA id u8-20020a1709026e0800b0017bb38e4588sm10382197plk.135.2022.11.09.23.31.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 09 Nov 2022 23:31:41 -0800 (PST) From: Chuang Wang Cc: Chuang Wang , Jakub Kicinski , "David S. Miller" , Eric Dumazet , Paolo Abeni , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] net: tun: rebuild error handling in tun_get_user Date: Thu, 10 Nov 2022 15:31:25 +0800 Message-Id: <20221110073125.692259-1-nashuiliang@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org The error handling in tun_get_user is very scattered. This patch unifies error handling, reduces duplication of code, and makes the logic clearer. Signed-off-by: Chuang Wang --- v1 -> v2: - fix problems based on Jakub Kicinski's comments v0 -> v1: - rename tags drivers/net/tun.c | 65 +++++++++++++++++++++-------------------------- 1 file changed, 29 insertions(+), 36 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 4bf2b268df4a..27109d1fd187 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1746,7 +1746,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, u32 rxhash = 0; int skb_xdp = 1; bool frags = tun_napi_frags_enabled(tfile); - enum skb_drop_reason drop_reason; + enum skb_drop_reason drop_reason = SKB_DROP_REASON_NOT_SPECIFIED; if (!(tun->flags & IFF_NO_PI)) { if (len < sizeof(pi)) @@ -1807,10 +1807,9 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, * skb was created with generic XDP routine. */ skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp); - if (IS_ERR(skb)) { - dev_core_stats_rx_dropped_inc(tun->dev); - return PTR_ERR(skb); - } + err = PTR_ERR_OR_ZERO(skb); + if (err) + goto drop; if (!skb) return total_len; } else { @@ -1835,13 +1834,9 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, noblock); } - if (IS_ERR(skb)) { - if (PTR_ERR(skb) != -EAGAIN) - dev_core_stats_rx_dropped_inc(tun->dev); - if (frags) - mutex_unlock(&tfile->napi_mutex); - return PTR_ERR(skb); - } + err = PTR_ERR_OR_ZERO(skb); + if (err) + goto drop; if (zerocopy) err = zerocopy_sg_from_iter(skb, from); @@ -1851,27 +1846,14 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, if (err) { err = -EFAULT; drop_reason = SKB_DROP_REASON_SKB_UCOPY_FAULT; -drop: - dev_core_stats_rx_dropped_inc(tun->dev); - kfree_skb_reason(skb, drop_reason); - if (frags) { - tfile->napi.skb = NULL; - mutex_unlock(&tfile->napi_mutex); - } - - return err; + goto drop; } } if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) { atomic_long_inc(&tun->rx_frame_errors); - kfree_skb(skb); - if (frags) { - tfile->napi.skb = NULL; - mutex_unlock(&tfile->napi_mutex); - } - - return -EINVAL; + err = -EINVAL; + goto free_skb; } switch (tun->flags & TUN_TYPE_MASK) { @@ -1887,9 +1869,8 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, pi.proto = htons(ETH_P_IPV6); break; default: - dev_core_stats_rx_dropped_inc(tun->dev); - kfree_skb(skb); - return -EINVAL; + err = -EINVAL; + goto drop; } } @@ -1931,11 +1912,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, if (ret != XDP_PASS) { rcu_read_unlock(); local_bh_enable(); - if (frags) { - tfile->napi.skb = NULL; - mutex_unlock(&tfile->napi_mutex); - } - return total_len; + goto unlock_frags; } } rcu_read_unlock(); @@ -2008,6 +1985,22 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, tun_flow_update(tun, rxhash, tfile); return total_len; + +drop: + if (err != -EAGAIN) + dev_core_stats_rx_dropped_inc(tun->dev); + +free_skb: + if (!IS_ERR_OR_NULL(skb)) + kfree_skb_reason(skb, drop_reason); + +unlock_frags: + if (frags) { + tfile->napi.skb = NULL; + mutex_unlock(&tfile->napi_mutex); + } + + return err ?: total_len; } static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)