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[73.241.150.70]) by smtp.gmail.com with ESMTPSA id q6sm18145350pgn.44.2019.10.13.12.30.42 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 13 Oct 2019 12:30:42 -0700 (PDT) Subject: Re: [PATCH] net: core: datagram: tidy up copy functions a bit To: Vito Caputo , davem@davemloft.net Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20191012115509.jrqe43yozs7kknv5@shells.gnugeneration.com> From: Eric Dumazet Message-ID: <8fab6f9c-70a6-02fd-5b2d-66a013c10a4f@gmail.com> Date: Sun, 13 Oct 2019 12:30:41 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20191012115509.jrqe43yozs7kknv5@shells.gnugeneration.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 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.