From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4EA0F171A9 for ; Mon, 22 May 2023 19:32:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CC9CDC433AE; Mon, 22 May 2023 19:32:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1684783944; bh=ArcQF516hMZWJ3h6Uf2CV1TL9M6mRuKJDgmBIIFqhA4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EkDuTAdKQF+HRpk2N6GxFjHE/2JritKPZFSdnxUfgWLTDlx+aQWKb674v2S53mYFm SanZiyqR+azbIj7G1l8CyDZL1ML4IFpIUM0vE627dRPqpFboQMKogA2xs3GudV+qY9 x2PWaY99ZmxQZGEiyp/mQvEBTQDvfP14+/gfV4vY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chuang Wang , "David S. Miller" , Sasha Levin Subject: [PATCH 6.1 214/292] net: tun: rebuild error handling in tun_get_user Date: Mon, 22 May 2023 20:09:31 +0100 Message-Id: <20230522190411.307114804@linuxfoundation.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230522190405.880733338@linuxfoundation.org> References: <20230522190405.880733338@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Chuang Wang [ Upstream commit ab00af85d2f886a8e4ace1342d9cc2b232eab6a8 ] 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 Signed-off-by: David S. Miller Stable-dep-of: 82b2bc279467 ("tun: Fix memory leak for detached NAPI queue.") Signed-off-by: Sasha Levin --- 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 91d198aff2f9a..65706824eb828 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1748,7 +1748,7 @@ 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)) @@ -1809,10 +1809,9 @@ 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 { @@ -1837,13 +1836,9 @@ 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); @@ -1853,27 +1848,14 @@ 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) { @@ -1889,9 +1871,8 @@ 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; } } @@ -1933,11 +1914,7 @@ 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(); @@ -2017,6 +1994,22 @@ 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) -- 2.39.2