tipc: donot create timers if subscription timeout = TIPC_WAIT_FOREVER

Until now, we create timers even for the subscription requests
with timeout = TIPC_WAIT_FOREVER.
This can be improved by avoiding timer creation when the timeout
is set to TIPC_WAIT_FOREVER.

In this commit, we introduce a check to creates timers only
when timeout != TIPC_WAIT_FOREVER.

Acked-by: Ying Xue <ying.xue@windriver.com>
Reviewed-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 3 deletions

diff --git a/net/tipc/subscr.c b/net/tipc/subscr.c
index 7d226ecb0490..22963cafd5ed 100644
--- a/net/tipc/subscr.c
+++ b/net/tipc/subscr.c
@@ -188,12 +188,14 @@ static struct tipc_subscriber *tipc_subscrb_create(int conid)
 static void tipc_subscrb_delete(struct tipc_subscriber *subscriber)
 {
         struct tipc_subscription *sub, *temp;
+        u32 timeout;
 
         spin_lock_bh(&subscriber->lock);
         /* Destroy any existing subscriptions for subscriber */
         list_for_each_entry_safe(sub, temp, &subscriber->subscrp_list,
                                  subscrp_list) {
-                if (del_timer(&sub->timer)) {
+                timeout = htohl(sub->evt.s.timeout, sub->swap);
+                if ((timeout == TIPC_WAIT_FOREVER) || del_timer(&sub->timer)) {
                         tipc_subscrp_delete(sub);
                         tipc_subscrb_put(subscriber);
                 }
@@ -217,13 +219,16 @@ static void tipc_subscrp_cancel(struct tipc_subscr *s,
                                 struct tipc_subscriber *subscriber)
 {
         struct tipc_subscription *sub, *temp;
+        u32 timeout;
 
         spin_lock_bh(&subscriber->lock);
         /* Find first matching subscription, exit if not found */
         list_for_each_entry_safe(sub, temp, &subscriber->subscrp_list,
                                  subscrp_list) {
                 if (!memcmp(s, &sub->evt.s, sizeof(struct tipc_subscr))) {
-                        if (del_timer(&sub->timer)) {
+                        timeout = htohl(sub->evt.s.timeout, sub->swap);
+                        if ((timeout == TIPC_WAIT_FOREVER) ||
+                            del_timer(&sub->timer)) {
                                 tipc_subscrp_delete(sub);
                                 tipc_subscrb_put(subscriber);
                         }
@@ -267,7 +272,6 @@ static struct tipc_subscription *tipc_subscrp_create(struct net *net,
         sub->swap = swap;
         memcpy(&sub->evt.s, s, sizeof(*s));
         atomic_inc(&tn->subscription_count);
-        setup_timer(&sub->timer, tipc_subscrp_timeout, (unsigned long)sub);
         return sub;
 }
 
@@ -290,6 +294,10 @@ static void tipc_subscrp_subscribe(struct net *net, struct tipc_subscr *s,
         spin_unlock_bh(&subscriber->lock);
 
         timeout = htohl(sub->evt.s.timeout, swap);
+        if (timeout == TIPC_WAIT_FOREVER)
+                return;
+
+        setup_timer(&sub->timer, tipc_subscrp_timeout, (unsigned long)sub);
         mod_timer(&sub->timer, jiffies + msecs_to_jiffies(timeout));
 }