From: ppisa <ppisa>
Date: Mon, 19 Apr 2004 00:50:39 +0000 (+0000)
Subject: Rearranged tests in canque_test_outslot for faster and more optimal behavior.
X-Git-Tag: CLT_COMM_CAN-lincan-0_2_2~14
X-Git-Url: http://rtime.felk.cvut.cz/gitweb/lincan.git/commitdiff_plain/1968cb90e13a25eac384cc901a3f6d31d4cb708a

Rearranged tests in canque_test_outslot for faster and more optimal behavior.
Some tests required additional loop for EMPTY and DEAD edge states.
---

diff --git a/lincan/src/can_queue.c b/lincan/src/can_queue.c
index b0c027e..c4130aa 100644
--- a/lincan/src/can_queue.c
+++ b/lincan/src/can_queue.c
@@ -313,6 +313,20 @@ int canque_test_outslot(struct canque_ends_t *qends,
 		while(!list_empty(&qends->active[prio])){
 			edge=list_entry(qends->active[prio].next,struct canque_edge_t,activepeers);
 			if(!canque_fifo_test_fl(&edge->fifo,DEAD)) {
+				/* The first test on unlocked FIFO */
+				if(canque_fifo_test_fl(&edge->fifo,EMPTY)) {
+					can_spin_lock(&edge->fifo.fifo_lock);
+					/* Test has to be repeated to ensure that EMPTY
+					   state has not been nagated when locking FIFO */
+					if(canque_fifo_test_fl(&edge->fifo,EMPTY)) {
+						canque_fifo_set_fl(&edge->fifo,INACTIVE);
+						list_del(&edge->activepeers);
+						list_add(&edge->activepeers,&qends->idle);
+						can_spin_unlock(&edge->fifo.fifo_lock);
+						continue;
+					}
+					can_spin_unlock(&edge->fifo.fifo_lock);
+				}
 				canque_edge_incref(edge);
 				can_spin_unlock_irqrestore(&qends->ends_lock, flags);
 				*qedgep=edge;
@@ -320,14 +334,16 @@ int canque_test_outslot(struct canque_ends_t *qends,
 				ret=canque_fifo_test_outslot(&edge->fifo, slotp);
 				if(ret>=0)
 					return ret;
+
+				canque_edge_decref(edge);
 				can_spin_lock_irqsave(&qends->ends_lock, flags);
-			}
-			can_spin_lock(&edge->fifo.fifo_lock);
-			if(canque_fifo_test_and_set_fl(&edge->fifo,INACTIVE)) {
+			} else {
+				can_spin_lock(&edge->fifo.fifo_lock);
+				canque_fifo_set_fl(&edge->fifo,INACTIVE);
 				list_del(&edge->activepeers);
 				list_add(&edge->activepeers,&qends->idle);
+				can_spin_unlock(&edge->fifo.fifo_lock);
 			}
-			can_spin_unlock(&edge->fifo.fifo_lock);
 		}
 	}
 	can_spin_unlock_irqrestore(&qends->ends_lock, flags);