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[149.6.153.186]) by smtp.gmail.com with ESMTPSA id 189sm2556920wmc.7.2019.10.29.06.51.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 29 Oct 2019 06:51:02 -0700 (PDT) From: Matteo Croce To: netdev@vger.kernel.org Cc: Jay Vosburgh , Veaceslav Falico , Andy Gospodarek , "David S . Miller " , Stanislav Fomichev , Daniel Borkmann , Song Liu , Alexei Starovoitov , Paul Blakey , linux-kernel@vger.kernel.org Subject: [PATCH net-next v2 1/4] flow_dissector: add meaningful comments Date: Tue, 29 Oct 2019 14:50:50 +0100 Message-Id: <20191029135053.10055-2-mcroce@redhat.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20191029135053.10055-1-mcroce@redhat.com> References: <20191029135053.10055-1-mcroce@redhat.com> MIME-Version: 1.0 X-MC-Unique: ZFe2rKfbOe2p_5iy3UQYog-1 X-Mimecast-Spam-Score: 0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Documents two piece of code which can't be understood at a glance. Signed-off-by: Matteo Croce --- include/net/flow_dissector.h | 1 + net/core/flow_dissector.c | 6 ++++++ 2 files changed, 7 insertions(+) diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h index 90bd210be060..7747af3cc500 100644 --- a/include/net/flow_dissector.h +++ b/include/net/flow_dissector.h @@ -282,6 +282,7 @@ struct flow_keys { struct flow_dissector_key_vlan cvlan; struct flow_dissector_key_keyid keyid; struct flow_dissector_key_ports ports; + /* 'addrs' must be the last member */ struct flow_dissector_key_addrs addrs; }; diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index 7c09d87d3269..affde70dad47 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -1374,6 +1374,9 @@ static inline size_t flow_keys_hash_length(const struct flow_keys *flow) { size_t diff = FLOW_KEYS_HASH_OFFSET + sizeof(flow->addrs); BUILD_BUG_ON((sizeof(*flow) - FLOW_KEYS_HASH_OFFSET) % sizeof(u32)); + /* flow.addrs MUST be the last member in struct flow_keys because + * different L3 protocols have different address length + */ BUILD_BUG_ON(offsetof(typeof(*flow), addrs) != sizeof(*flow) - sizeof(flow->addrs)); @@ -1421,6 +1424,9 @@ __be32 flow_get_u32_dst(const struct flow_keys *flow) } EXPORT_SYMBOL(flow_get_u32_dst); +/* Sort the source and destination IP (and the ports if the IP are the same), + * to have consistent hash within the two directions + */ static inline void __flow_hash_consistentify(struct flow_keys *keys) { int addr_diff, i;