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, 4 insertions, 37 deletions

diff --git a/net/tipc/link.h b/net/tipc/link.h
index dc27bb62b1f5..a65770bf647c 100644
--- a/net/tipc/link.h
+++ b/net/tipc/link.h
@@ -151,7 +151,7 @@ struct tipc_link {
 
 	/* Management and link supervision data */
 	unsigned int flags;
-	u32 checkpoint;
+	u16 checkpoint;
 	u32 peer_session;
 	u32 peer_bearer_id;
 	u32 bearer_id;
@@ -185,13 +185,13 @@ struct tipc_link {
 		u16 len;
 		u16 limit;
 	} backlog[5];
-	u32 next_out_no;
+	u16 next_out_no;
+	u16 last_retransmitted;
 	u32 window;
-	u32 last_retransmitted;
 	u32 stale_count;
 
 	/* Reception */
-	u32 next_in_no;
+	u16 next_in_no;
 	u32 rcv_unacked;
 	struct sk_buff_head deferdq;
 	struct sk_buff_head inputq;
@@ -245,39 +245,6 @@ int tipc_nl_link_reset_stats(struct sk_buff *skb, struct genl_info *info);
 int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[]);
 void link_prepare_wakeup(struct tipc_link *l);
 
-/*
- * Link sequence number manipulation routines (uses modulo 2**16 arithmetic)
- */
-static inline u32 buf_seqno(struct sk_buff *buf)
-{
-	return msg_seqno(buf_msg(buf));
-}
-
-static inline u32 mod(u32 x)
-{
-	return x & 0xffffu;
-}
-
-static inline int less_eq(u32 left, u32 right)
-{
-	return mod(right - left) < 32768u;
-}
-
-static inline int more(u32 left, u32 right)
-{
-	return !less_eq(left, right);
-}
-
-static inline int less(u32 left, u32 right)
-{
-	return less_eq(left, right) && (mod(right) != mod(left));
-}
-
-static inline u32 lesser(u32 left, u32 right)
-{
-	return less_eq(left, right) ? left : right;
-}
-
 static inline u32 link_own_addr(struct tipc_link *l)
 {
 	return msg_prevnode(l->pmsg);