tipc: simplify packet sequence number handling

Although the sequence number in the TIPC protocol is 16 bits, we have
until now stored it internally as an unsigned 32 bits integer.
We got around this by always doing explicit modulo-65535 operations
whenever we need to access a sequence number.

We now make the incoming and outgoing sequence numbers to unsigned
16-bit integers, and remove the modulo operations where applicable.

We also move the arithmetic inline functions for 16 bit integers
to core.h, and the function buf_seqno() to msg.h, so they can easily
be accessed from anywhere in the code.

Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 6 deletions

diff --git a/net/tipc/msg.h b/net/tipc/msg.h
index e1d3595e..6ca2366 100644
--- a/net/tipc/msg.h
+++ b/net/tipc/msg.h
@@ -313,12 +313,12 @@ static inline void msg_set_lookup_scope(struct tipc_msg *m, u32 n)
 	msg_set_bits(m, 1, 19, 0x3, n);
 }
 
-static inline u32 msg_bcast_ack(struct tipc_msg *m)
+static inline u16 msg_bcast_ack(struct tipc_msg *m)
 {
 	return msg_bits(m, 1, 0, 0xffff);
 }
 
-static inline void msg_set_bcast_ack(struct tipc_msg *m, u32 n)
+static inline void msg_set_bcast_ack(struct tipc_msg *m, u16 n)
 {
 	msg_set_bits(m, 1, 0, 0xffff, n);
 }
@@ -327,22 +327,22 @@ static inline void msg_set_bcast_ack(struct tipc_msg *m, u32 n)
 /*
  * Word 2
  */
-static inline u32 msg_ack(struct tipc_msg *m)
+static inline u16 msg_ack(struct tipc_msg *m)
 {
 	return msg_bits(m, 2, 16, 0xffff);
 }
 
-static inline void msg_set_ack(struct tipc_msg *m, u32 n)
+static inline void msg_set_ack(struct tipc_msg *m, u16 n)
 {
 	msg_set_bits(m, 2, 16, 0xffff, n);
 }
 
-static inline u32 msg_seqno(struct tipc_msg *m)
+static inline u16 msg_seqno(struct tipc_msg *m)
 {
 	return msg_bits(m, 2, 0, 0xffff);
 }
 
-static inline void msg_set_seqno(struct tipc_msg *m, u32 n)
+static inline void msg_set_seqno(struct tipc_msg *m, u16 n)
 {
 	msg_set_bits(m, 2, 0, 0xffff, n);
 }
@@ -782,6 +782,11 @@ bool tipc_msg_lookup_dest(struct net *net, struct sk_buff *skb, u32 *dnode,
 			  int *err);
 struct sk_buff *tipc_msg_reassemble(struct sk_buff_head *list);
 
+static inline u16 buf_seqno(struct sk_buff *skb)
+{
+	return msg_seqno(buf_msg(skb));
+}
+
 /* tipc_skb_peek(): peek and reserve first buffer in list
  * @list: list to be peeked in
  * Returns pointer to first buffer in list, if any