Improve round robin stream scheduler and cleanup some code.

Approved by: rrs (mentor)
MFC after: 3 days

1 files changed, 24 insertions, 21 deletions

diff --git a/sys/netinet/sctp_output.c b/sys/netinet/sctp_output.c
index 02bca90..8c29f70 100644
--- a/sys/netinet/sctp_output.c
+++ b/sys/netinet/sctp_output.c
@@ -5605,13 +5605,10 @@ sctp_insert_on_wheel(struct sctp_tcb *stcb,
 	if (holds_lock == 0) {
 		SCTP_TCB_SEND_LOCK(stcb);
 	}
-	if ((strq->next_spoke.tqe_next) ||
-	    (strq->next_spoke.tqe_prev)) {
-		/* already on wheel */
-		goto outof_here;
+	if ((strq->next_spoke.tqe_next == NULL) &&
+	    (strq->next_spoke.tqe_prev == NULL)) {
+		TAILQ_INSERT_TAIL(&asoc->out_wheel, strq, next_spoke);
 	}
-	TAILQ_INSERT_TAIL(&asoc->out_wheel, strq, next_spoke);
-outof_here:
 	if (holds_lock == 0) {
 		SCTP_TCB_SEND_UNLOCK(stcb);
 	}
@@ -5624,19 +5621,26 @@ sctp_remove_from_wheel(struct sctp_tcb *stcb,
     int holds_lock)
 {
 	/* take off and then setup so we know it is not on the wheel */
-	if (holds_lock == 0)
+	if (holds_lock == 0) {
 		SCTP_TCB_SEND_LOCK(stcb);
-	if (TAILQ_FIRST(&strq->outqueue)) {
-		/* more was added */
-		if (holds_lock == 0)
-			SCTP_TCB_SEND_UNLOCK(stcb);
-		return;
 	}
-	TAILQ_REMOVE(&asoc->out_wheel, strq, next_spoke);
-	strq->next_spoke.tqe_next = NULL;
-	strq->next_spoke.tqe_prev = NULL;
-	if (holds_lock == 0)
+	if (TAILQ_EMPTY(&strq->outqueue)) {
+		if (asoc->last_out_stream == strq) {
+			asoc->last_out_stream = TAILQ_PREV(asoc->last_out_stream, sctpwheel_listhead, next_spoke);
+			if (asoc->last_out_stream == NULL) {
+				asoc->last_out_stream = TAILQ_LAST(&asoc->out_wheel, sctpwheel_listhead);
+			}
+			if (asoc->last_out_stream == strq) {
+				asoc->last_out_stream = NULL;
+			}
+		}
+		TAILQ_REMOVE(&asoc->out_wheel, strq, next_spoke);
+		strq->next_spoke.tqe_next = NULL;
+		strq->next_spoke.tqe_prev = NULL;
+	}
+	if (holds_lock == 0) {
 		SCTP_TCB_SEND_UNLOCK(stcb);
+	}
 }
 
 static void
@@ -7185,7 +7189,7 @@ sctp_fill_outqueue(struct sctp_tcb *stcb,
     struct sctp_nets *net, int frag_point, int eeor_mode, int *quit_now)
 {
 	struct sctp_association *asoc;
-	struct sctp_stream_out *strq, *strqn, *strqt;
+	struct sctp_stream_out *strq, *strqn;
 	int goal_mtu, moved_how_much, total_moved = 0, bail = 0;
 	int locked, giveup;
 	struct sctp_stream_queue_pending *sp;
@@ -7261,11 +7265,10 @@ sctp_fill_outqueue(struct sctp_tcb *stcb,
 				break;
 		} else {
 			asoc->locked_on_sending = NULL;
-			strqt = sctp_select_a_stream(stcb, asoc);
-			if (TAILQ_FIRST(&strq->outqueue) == NULL) {
+			if (TAILQ_EMPTY(&strq->outqueue)) {
 				if (strq == strqn) {
 					/* Must move start to next one */
-					strqn = TAILQ_NEXT(asoc->last_out_stream, next_spoke);
+					strqn = TAILQ_NEXT(strq, next_spoke);
 					if (strqn == NULL) {
 						strqn = TAILQ_FIRST(&asoc->out_wheel);
 						if (strqn == NULL) {
@@ -7278,7 +7281,7 @@ sctp_fill_outqueue(struct sctp_tcb *stcb,
 			if ((giveup) || bail) {
 				break;
 			}
-			strq = strqt;
+			strq = sctp_select_a_stream(stcb, asoc);
 			if (strq == NULL) {
 				break;
 			}