From 0bd00f72312a79900d211e735b135c220ddd0d68 Mon Sep 17 00:00:00 2001
From: Andre Noll <maan@systemlinux.org>
Date: Thu, 14 Jul 2011 08:17:08 +0200
Subject: [PATCH] vss: Clean up timeout computations.

By passing the sched struct to vss_compute_timeout() we can get
rid of the static the_timeout struct in vss_compute_timeout(). The
previous patch, which made the timeout helper functions of sched.c
return whether the given barrier is in the past, allows to simplify
the timeout code of vss.c a bit.

The patch also combines the general timeout computations and the
computation for FEC slices into a single function.
---
 vss.c | 85 ++++++++++++++++++++---------------------------------------
 1 file changed, 29 insertions(+), 56 deletions(-)

diff --git a/vss.c b/vss.c
index 2068563c..b9afc8ed 100644
--- a/vss.c
+++ b/vss.c
@@ -688,26 +688,6 @@ static int next_slice_is_due(struct fec_client *fc, struct timeval *diff)
 	return ret < 0? 1 : 0;
 }
 
-static void compute_slice_timeout(struct timeval *timeout)
-{
-	struct fec_client *fc;
-
-	list_for_each_entry(fc, &fec_client_list, node) {
-		struct timeval diff;
-
-		if (fc->state != FEC_STATE_READY_TO_RUN)
-			continue;
-		if (next_slice_is_due(fc, &diff)) {
-			timeout->tv_sec = 0;
-			timeout->tv_usec = 0;
-			return;
-		}
-		/* timeout = min(timeout, diff) */
-		if (tv_diff(&diff, timeout, NULL) < 0)
-			*timeout = diff;
-	}
-}
-
 static void set_eof_barrier(struct vss_task *vsst)
 {
 	struct fec_client *fc;
@@ -798,42 +778,38 @@ static int chk_barrier(const char *bname, const struct timeval *barrier,
 	return -1;
 }
 
-/*
- * != NULL: timeout for next chunk
- * NULL: nothing to do
- */
-static struct timeval *vss_compute_timeout(struct vss_task *vsst)
+static void vss_compute_timeout(struct sched *s, struct vss_task *vsst)
 {
-	static struct timeval the_timeout;
-	struct timeval next_chunk;
-
-	if (vss_next() && vsst->map) {
-		/* only sleep a bit, nec*/
-		the_timeout.tv_sec = 0;
-		the_timeout.tv_usec = 100;
-		return &the_timeout;
-	}
-	if (chk_barrier("autoplay_delay", &vsst->autoplay_barrier,
-			&the_timeout, 1) < 0)
-		return &the_timeout;
-	if (chk_barrier("eof", &vsst->eof_barrier, &the_timeout, 1) < 0)
-		return &the_timeout;
-	if (chk_barrier("data send", &vsst->data_send_barrier,
-			&the_timeout, 1) < 0)
-		return &the_timeout;
+	struct timeval tv;
+	struct fec_client *fc;
+
 	if (!vss_playing() || !vsst->map)
-		return NULL;
+		return;
+	if (vss_next() && vsst->map) /* only sleep a bit, nec*/
+		return sched_request_timeout_ms(100, s);
+
+	/* Each of these barriers must have passed until we may proceed */
+	if (sched_request_barrier(&vsst->autoplay_barrier, s) == 1)
+		return;
+	if (sched_request_barrier(&vsst->eof_barrier, s) == 1)
+		return;
+	if (sched_request_barrier(&vsst->data_send_barrier, s) == 1)
+		return;
+	/*
+	 * Compute the select timeout as the minimal time until the next
+	 * chunk/slice is due for any client.
+	 */
 	compute_chunk_time(mmd->chunks_sent, &mmd->afd.afhi.chunk_tv,
-		&mmd->stream_start, &next_chunk);
-	if (chk_barrier("chunk", &next_chunk, &the_timeout, 0) >= 0) {
-		/* chunk is due or bof */
-		the_timeout.tv_sec = 0;
-		the_timeout.tv_usec = 0;
-		return &the_timeout;
+		&mmd->stream_start, &tv);
+	if (sched_request_barrier_or_min_delay(&tv, s) == 0)
+		return;
+	list_for_each_entry(fc, &fec_client_list, node) {
+		if (fc->state != FEC_STATE_READY_TO_RUN)
+			continue;
+		if (next_slice_is_due(fc, &tv))
+			return sched_min_delay(s);
+		sched_request_timeout(&tv, s);
 	}
-	/* compute min of current timeout and next slice time */
-	compute_slice_timeout(&the_timeout);
-	return &the_timeout;
 }
 
 static void vss_eof(struct vss_task *vsst)
@@ -902,7 +878,6 @@ static void set_mmd_offset(void)
 static void vss_pre_select(struct sched *s, struct task *t)
 {
 	int i;
-	struct timeval *tv;
 	struct vss_task *vsst = container_of(t, struct vss_task, task);
 
 	if (!vsst->map || vss_next() || vss_paused() || vss_repos()) {
@@ -940,9 +915,7 @@ static void vss_pre_select(struct sched *s, struct task *t)
 			continue;
 		senders[i].pre_select(&s->max_fileno, &s->rfds, &s->wfds);
 	}
-	tv = vss_compute_timeout(vsst);
-	if (tv)
-		sched_request_timeout(tv, s);
+	vss_compute_timeout(s, vsst);
 }
 
 static int recv_afs_msg(int afs_socket, int *fd, uint32_t *code, uint32_t *data)
-- 
2.39.2