From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DF710C4360C for ; Sun, 13 Oct 2019 20:02:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BE70E207FF for ; Sun, 13 Oct 2019 20:02:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729534AbfJMUB6 (ORCPT ); Sun, 13 Oct 2019 16:01:58 -0400 Received: from shells.gnugeneration.com ([66.240.222.126]:41716 "EHLO shells.gnugeneration.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727492AbfJMUB6 (ORCPT ); Sun, 13 Oct 2019 16:01:58 -0400 Received: by shells.gnugeneration.com (Postfix, from userid 1000) id 5A0FB1A40559; Sun, 13 Oct 2019 13:01:58 -0700 (PDT) Date: Sun, 13 Oct 2019 13:01:58 -0700 From: Vito Caputo To: Eric Dumazet Cc: davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] net: core: datagram: tidy up copy functions a bit Message-ID: <20191013200158.mhvwkdnsjk7ecuqu@shells.gnugeneration.com> References: <20191012115509.jrqe43yozs7kknv5@shells.gnugeneration.com> <8fab6f9c-70a6-02fd-5b2d-66a013c10a4f@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8fab6f9c-70a6-02fd-5b2d-66a013c10a4f@gmail.com> User-Agent: NeoMutt/20170113 (1.7.2) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Sun, Oct 13, 2019 at 12:30:41PM -0700, Eric Dumazet wrote: > > > On 10/12/19 4:55 AM, Vito Caputo wrote: > > Eliminate some verbosity by using min() macro and consolidating some > > things, also fix inconsistent zero tests (! vs. == 0). > > > > Signed-off-by: Vito Caputo > > --- > > net/core/datagram.c | 44 ++++++++++++++------------------------------ > > 1 file changed, 14 insertions(+), 30 deletions(-) > > > > diff --git a/net/core/datagram.c b/net/core/datagram.c > > index 4cc8dc5db2b7..08d403f93952 100644 > > --- a/net/core/datagram.c > > +++ b/net/core/datagram.c > > @@ -413,13 +413,11 @@ static int __skb_datagram_iter(const struct sk_buff *skb, int offset, > > struct iov_iter *), void *data) > > { > > int start = skb_headlen(skb); > > - int i, copy = start - offset, start_off = offset, n; > > + int i, copy, start_off = offset, n; > > struct sk_buff *frag_iter; > > > > /* Copy header. */ > > - if (copy > 0) { > > - if (copy > len) > > - copy = len; > > + if ((copy = min(start - offset, len)) > 0) { > > No, we prefer not having this kind of construct anymore. > > This refactoring looks unnecessary code churn, making our future backports not > clean cherry-picks. > > Simply making sure this patch does not bring a regression is very time consuming. Should I not bother submitting patches for such cleanups? I submitted another, more trivial patch, is it also considered unnecessary churn: --- Author: Vito Caputo Date: Sat Oct 12 17:10:41 2019 -0700 net: core: skbuff: skb_checksum_setup() drop err Return directly from all switch cases, no point in storing in err. Signed-off-by: Vito Caputo diff --git a/net/core/skbuff.c b/net/core/skbuff.c index f5f904f46893..c59b68a413b5 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -4888,23 +4888,14 @@ static int skb_checksum_setup_ipv6(struct sk_buff *skb, bool recalculate) */ int skb_checksum_setup(struct sk_buff *skb, bool recalculate) { - int err; - switch (skb->protocol) { case htons(ETH_P_IP): - err = skb_checksum_setup_ipv4(skb, recalculate); - break; - + return skb_checksum_setup_ipv4(skb, recalculate); case htons(ETH_P_IPV6): - err = skb_checksum_setup_ipv6(skb, recalculate); - break; - + return skb_checksum_setup_ipv6(skb, recalculate); default: - err = -EPROTO; - break; + return -EPROTO; } - - return err; } EXPORT_SYMBOL(skb_checksum_setup); --- Asking to calibrate my thresholds to yours, since I was planning to volunteer some time each evening to reading kernel code and submitting any obvious cleanups. Thanks, Vito Caputo