From: Matteo Croce <mcroce@redhat.com>
Date: Tue, 29 Oct 2019 14:50:50 +0100
Subject: flow_dissector: add meaningful comments
Patch-mainline: v5.5-rc1
Git-commit: 98298e6ca6d5908f96e529e70a254a4d5bf754e7
References: bsc#1154353
Documents two piece of code which can't be understood at a glance.
Signed-off-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
include/net/flow_dissector.h | 1 +
net/core/flow_dissector.c | 6 ++++--
2 files changed, 5 insertions(+), 2 deletions(-)
--- a/include/net/flow_dissector.h
+++ b/include/net/flow_dissector.h
@@ -283,6 +283,7 @@ 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;
};
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -1399,8 +1399,7 @@ static const void *flow_keys_hash_start(
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(offsetof(typeof(*flow), addrs) !=
- sizeof(*flow) - sizeof(flow->addrs));
+ BUILD_BUG_ON((sizeof(*flow) - FLOW_KEYS_HASH_OFFSET) % sizeof(u32));
switch (flow->control.addr_type) {
case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
@@ -1446,6 +1445,9 @@ __be32 flow_get_u32_dst(const struct flo
}
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;