tipc: simplify endianness handling in topology subscriber

Because of the requirement for total distribution transparency, users
send subscriptions and receive topology events in their own host format.
It is up to the topology server to determine this format and do the
correct conversions to and from its own host format when needed.

Until now, this has been handled in a rather non-transparent way inside
the topology server and subscriber code, leading to unnecessary
complexity when creating subscriptions and issuing events.

We now improve this situation by adding two new macros, tipc_sub_read()
and tipc_evt_write(). Both those functions calculate the need for
conversion internally before performing their respective operations.
Hence, all handling of such conversions become transparent to the rest
of the code.

Acked-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, 25 insertions, 17 deletions

diff --git a/net/tipc/name_table.c b/net/tipc/name_table.c
index c0ca7be46f7a..2fbd0a20a958 100644
--- a/net/tipc/name_table.c
+++ b/net/tipc/name_table.c
@@ -412,18 +412,22 @@ found:
  * sequence overlapping with the requested sequence
  */
 static void tipc_nameseq_subscribe(struct name_seq *nseq,
-				   struct tipc_subscription *s,
-				   bool status)
+				   struct tipc_subscription *sub)
 {
 	struct sub_seq *sseq = nseq->sseqs;
 	struct tipc_name_seq ns;
+	struct tipc_subscr *s = &sub->evt.s;
+	bool no_status;
 
-	tipc_subscrp_convert_seq(&s->evt.s.seq, s->swap, &ns);
+	ns.type = tipc_sub_read(s, seq.type);
+	ns.lower = tipc_sub_read(s, seq.lower);
+	ns.upper = tipc_sub_read(s, seq.upper);
+	no_status = tipc_sub_read(s, filter) & TIPC_SUB_NO_STATUS;
 
-	tipc_subscrp_get(s);
-	list_add(&s->nameseq_list, &nseq->subscriptions);
+	tipc_subscrp_get(sub);
+	list_add(&sub->nameseq_list, &nseq->subscriptions);
 
-	if (!status || !sseq)
+	if (no_status || !sseq)
 		return;
 
 	while (sseq != &nseq->sseqs[nseq->first_free]) {
@@ -433,7 +437,7 @@ static void tipc_nameseq_subscribe(struct name_seq *nseq,
 			int must_report = 1;
 
 			list_for_each_entry(crs, &info->zone_list, zone_list) {
-				tipc_subscrp_report_overlap(s, sseq->lower,
+				tipc_subscrp_report_overlap(sub, sseq->lower,
 							    sseq->upper,
 							    TIPC_PUBLISHED,
 							    crs->ref, crs->node,
@@ -808,11 +812,12 @@ int tipc_nametbl_withdraw(struct net *net, u32 type, u32 lower, u32 ref,
 /**
  * tipc_nametbl_subscribe - add a subscription object to the name table
  */
-void tipc_nametbl_subscribe(struct tipc_subscription *s, bool status)
+void tipc_nametbl_subscribe(struct tipc_subscription *sub)
 {
-	struct tipc_server *srv = s->server;
+	struct tipc_server *srv = sub->server;
 	struct tipc_net *tn = tipc_net(srv->net);
-	u32 type = tipc_subscrp_convert_seq_type(s->evt.s.seq.type, s->swap);
+	struct tipc_subscr *s = &sub->evt.s;
+	u32 type = tipc_sub_read(s, seq.type);
 	int index = hash(type);
 	struct name_seq *seq;
 	struct tipc_name_seq ns;
@@ -823,10 +828,12 @@ void tipc_nametbl_subscribe(struct tipc_subscription *s, bool status)
 		seq = tipc_nameseq_create(type, &tn->nametbl->seq_hlist[index]);
 	if (seq) {
 		spin_lock_bh(&seq->lock);
-		tipc_nameseq_subscribe(seq, s, status);
+		tipc_nameseq_subscribe(seq, sub);
 		spin_unlock_bh(&seq->lock);
 	} else {
-		tipc_subscrp_convert_seq(&s->evt.s.seq, s->swap, &ns);
+		ns.type = tipc_sub_read(s, seq.type);
+		ns.lower = tipc_sub_read(s, seq.lower);
+		ns.upper = tipc_sub_read(s, seq.upper);
 		pr_warn("Failed to create subscription for {%u,%u,%u}\n",
 			ns.type, ns.lower, ns.upper);
 	}
@@ -836,19 +843,20 @@ void tipc_nametbl_subscribe(struct tipc_subscription *s, bool status)
 /**
  * tipc_nametbl_unsubscribe - remove a subscription object from name table
  */
-void tipc_nametbl_unsubscribe(struct tipc_subscription *s)
+void tipc_nametbl_unsubscribe(struct tipc_subscription *sub)
 {
-	struct tipc_server *srv = s->server;
+	struct tipc_server *srv = sub->server;
+	struct tipc_subscr *s = &sub->evt.s;
 	struct tipc_net *tn = tipc_net(srv->net);
 	struct name_seq *seq;
-	u32 type = tipc_subscrp_convert_seq_type(s->evt.s.seq.type, s->swap);
+	u32 type = tipc_sub_read(s, seq.type);
 
 	spin_lock_bh(&tn->nametbl_lock);
 	seq = nametbl_find_seq(srv->net, type);
 	if (seq != NULL) {
 		spin_lock_bh(&seq->lock);
-		list_del_init(&s->nameseq_list);
-		tipc_subscrp_put(s);
+		list_del_init(&sub->nameseq_list);
+		tipc_subscrp_put(sub);
 		if (!seq->first_free && list_empty(&seq->subscriptions)) {
 			hlist_del_init_rcu(&seq->ns_list);
 			kfree(seq->sseqs);