Re: [PATCH net-next 1/4] flow_dissector: add meaningful comments

[Simon Horman]

On Mon, Oct 21, 2019 at 10:09:45PM +0200, Matteo Croce wrote:
> Documents two piece of code which can't be understood at a glance.
> 
> Signed-off-by: Matteo Croce 

Reviewed-by: Simon Horman 

> ---
>  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;
> -- 
> 2.21.0
> 

[PATCH net-next 1/4] flow_dissector: add meaningful comments

[Matteo Croce]

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;
-- 
2.21.0