Use new select loop primitives in submission thread

miner.c

@@ -3814,8 +3814,11 @@ struct submit_work_state {
 
 static int my_curl_timer_set(__maybe_unused CURLM *curlm, long timeout_ms, void *userp)
 {
-	long *timeout = userp;
-	*timeout = timeout_ms;
+	struct timeval *tvp_timer = userp;
+	if (timeout_ms == -1)
+		tvp_timer->tv_sec = -1;
+	else
+		timer_set_delay_from_now(tvp_timer, timeout_ms * 1000);
 	return 0;
 }
 
@@ -3957,7 +3960,7 @@ static void *submit_work_thread(__maybe_unused void *userdata)
 {
 	int wip = 0;
 	CURLM *curlm;
-	long curlm_timeout_ms = -1;
+	struct timeval curlm_timer;
 	struct submit_work_state *sws, **swsp;
 	struct submit_work_state *write_sws = NULL;
 	unsigned tsreduce = 0;
@@ -3969,12 +3972,13 @@ static void *submit_work_thread(__maybe_unused void *userdata)
 	applog(LOG_DEBUG, "Creating extra submit work thread");
 
 	curlm = curl_multi_init();
+	curlm_timer.tv_sec = -1;
+	curl_multi_setopt(curlm, CURLMOPT_TIMERDATA, &curlm_timer);
 	curl_multi_setopt(curlm, CURLMOPT_TIMERFUNCTION, my_curl_timer_set);
-	curl_multi_setopt(curlm, CURLMOPT_TIMERDATA, &curlm_timeout_ms);
 
 	fd_set rfds, wfds, efds;
 	int maxfd;
-	struct timeval timeout, *timeoutp;
+	struct timeval tv_timeout, tv_now;
 	int n;
 	CURLMsg *cm;
 	FD_ZERO(&rfds);
@@ -3985,6 +3989,8 @@ static void *submit_work_thread(__maybe_unused void *userdata)
 		if (FD_ISSET(submit_waiting_notifier[0], &rfds)) {
 			notifier_read(submit_waiting_notifier);
 		}
+		
+		// Receive any new submissions
 		while (!list_empty(&submit_waiting)) {
 			struct work *work = list_entry(submit_waiting.next, struct work, list);
 			list_del(&work->list);
@@ -4002,6 +4008,7 @@ static void *submit_work_thread(__maybe_unused void *userdata)
 				free_work(work);
 			}
 		}
+		
 		if (unlikely(shutting_down && !wip))
 			break;
 		mutex_unlock(&submitting_lock);
@@ -4009,14 +4016,13 @@ static void *submit_work_thread(__maybe_unused void *userdata)
 		FD_ZERO(&rfds);
 		FD_ZERO(&wfds);
 		FD_ZERO(&efds);
+		tv_timeout.tv_sec = -1;
+		
+		// Setup cURL with select
 		curl_multi_fdset(curlm, &rfds, &wfds, &efds, &maxfd);
-		if (curlm_timeout_ms >= 0) {
-			timeout.tv_sec = curlm_timeout_ms / 1000;
-			timeout.tv_usec = (curlm_timeout_ms % 1000) * 1000;
-			timeoutp = &timeout;
-		} else
-			timeoutp = NULL;
+		reduce_timeout_to(&tv_timeout, &curlm_timer);
 		
+		// Setup waiting stratum submissions with select
 		for (swsp = &write_sws; (sws = *swsp); ) {
 			int fd = sws->work->pool->sock;
 			if (fd == INVSOCK) {
@@ -4029,8 +4035,7 @@ static void *submit_work_thread(__maybe_unused void *userdata)
 				continue;
 			}
 			FD_SET(fd, &wfds);
-			if (fd > maxfd)
-				maxfd = fd;
+			set_maxfd(&maxfd, fd);
 			swsp = &sws->next;
 		}
 		if (tsreduce) {
@@ -4040,15 +4045,18 @@ static void *submit_work_thread(__maybe_unused void *userdata)
 			tsreduce = 0;
 		}
 		
+		// Setup "submit waiting" notifier with select
 		FD_SET(submit_waiting_notifier[0], &rfds);
-		if (submit_waiting_notifier[0] > maxfd)
-			maxfd = submit_waiting_notifier[0];
+		set_maxfd(&maxfd, submit_waiting_notifier[0]);
 		
-		if (select(maxfd+1, &rfds, &wfds, &efds, timeoutp) < 0) {
+		// Wait for something interesting to happen :)
+		gettimeofday(&tv_now, NULL);
+		if (select(maxfd+1, &rfds, &wfds, &efds, select_timeout(&tv_timeout, &tv_now)) < 0) {
 			FD_ZERO(&rfds);
 			continue;
 		}
 		
+		// Handle any stratum ready-to-write results
 		for (swsp = &write_sws; (sws = *swsp); ) {
 			int fd = sws->work->pool->sock;
 			if (fd == -1 || !FD_ISSET(fd, &wfds)) {
@@ -4079,6 +4087,7 @@ static void *submit_work_thread(__maybe_unused void *userdata)
 			--wip;
 		}
 		
+		// Handle any cURL activities
 		curl_multi_perform(curlm, &n);
 		while( (cm = curl_multi_info_read(curlm, &n)) ) {
 			if (cm->msg == CURLMSG_DONE)