Rewrite the convoluted get_work() function to be much simpler and roll work as much as possible with each new work item.

cgminer.c

@@ -1525,19 +1525,30 @@ out:
 	return rc;
 }
 
+static int inc_totalwork(void)
+{
+	int ret;
+
+	mutex_lock(&control_lock);
+	ret = total_work++;
+	mutex_unlock(&control_lock);
+	return ret;
+}
+
 static struct work *make_work(void)
 {
 	struct work *work = calloc(1, sizeof(struct work));
 
 	if (unlikely(!work))
 		quit(1, "Failed to calloc work in make_work");
-	work->id = total_work++;
+	work->id = inc_totalwork();
 	return work;
 }
 
 static void free_work(struct work *work)
 {
 	free(work);
+	work = NULL;
 }
 
 static void workio_cmd_free(struct workio_cmd *wc)
@@ -2984,7 +2995,7 @@ static void roll_work(struct work *work)
 
 	/* This is now a different work item so it needs a different ID for the
 	 * hashtable */
-	work->id = total_work++;
+	work->id = inc_totalwork();
 }
 
 static bool reuse_work(struct work *work)
@@ -2996,103 +3007,83 @@ static bool reuse_work(struct work *work)
 	return false;
 }
 
-static bool get_work(struct work *work, bool requested, struct thr_info *thr,
-		     const int thr_id)
+static void roll_cloned(struct work *work)
 {
-	bool newreq = false, ret = false;
-	struct timespec abstime = {};
+	struct work *work_clone = make_work();
+
+	memcpy(work_clone, work, sizeof(struct work));
+	while (reuse_work(work)) {
+		work_clone->clone = true;
+		if (opt_debug)
+			applog(LOG_DEBUG, "Pushing rolled cloned work to stage thread");
+		if (unlikely(!stage_work(work_clone)))
+			break;
+		work_clone = make_work();
+		memcpy(work_clone, work, sizeof(struct work));
+	}
+	free_work(work_clone);
+}
+
+static struct work *get_work(bool requested, struct thr_info *thr, const int thr_id)
+{
+	struct timespec abstime = {0, 0};
+	struct work *work = NULL;
+	bool newreq = false;
 	struct timeval now;
-	struct work *work_heap;
 	struct pool *pool;
-	int failures = 0;
 
 	/* Tell the watchdog thread this thread is waiting on getwork and
 	 * should not be restarted */
 	thread_reportout(thr);
-retry:
-	pool = current_pool();
-	if (!requested || requests_queued() < opt_queue) {
-		if (unlikely(!queue_request(thr, true))) {
-			applog(LOG_WARNING, "Failed to queue_request in get_work");
-			goto out;
-		}
-		newreq = true;
-	}
 
-	if (reuse_work(work)) {
-		ret = true;
-		goto out;
-	}
-
-	if (requested && !newreq && !requests_staged() && requests_queued() >= mining_threads &&
-	    !pool_tset(pool, &pool->lagging)) {
-		applog(LOG_WARNING, "Pool %d not providing work fast enough", pool->pool_no);
-		pool->getfail_occasions++;
-		total_go++;
-	}
+	while (!work) {
+		pool = current_pool();
+		if (!requested || requests_queued() < opt_queue) {
+			if (unlikely(!queue_request(thr, true)))
+				quit(1, "Failed to queue_request in get_work");
+			newreq = true;
+		}
 
-	newreq = requested = false;
-	gettimeofday(&now, NULL);
-	abstime.tv_sec = now.tv_sec + 60;
+		if (requested && !newreq && !requests_staged() && requests_queued() >= mining_threads &&
+		    !pool_tset(pool, &pool->lagging)) {
+			applog(LOG_WARNING, "Pool %d not providing work fast enough", pool->pool_no);
+			pool->getfail_occasions++;
+			total_go++;
+		}
 
-	if (opt_debug)
-		applog(LOG_DEBUG, "Popping work from get queue to get work");
+		newreq = requested = false;
+		gettimeofday(&now, NULL);
+		abstime.tv_sec = now.tv_sec + 60;
 
-	/* wait for 1st response, or get cached response */
-	work_heap = hash_pop(&abstime);
-	if (unlikely(!work_heap)) {
-		/* Attempt to switch pools if this one times out */
-		pool_died(pool);
-		goto retry;
-	}
+		if (opt_debug)
+			applog(LOG_DEBUG, "Popping work from get queue to get work");
 
-	if (stale_work(work_heap, false)) {
-		dec_queued();
-		discard_work(work_heap);
-		goto retry;
+		/* wait for 1st response, or get cached response */
+		work = hash_pop(&abstime);
+		if (unlikely(!work)) {
+			/* Attempt to switch pools if this one times out */
+			pool_died(pool);
+		} else if (stale_work(work, false)) {
+			dec_queued();
+			discard_work(work);
+		}
 	}
 
-	pool = work_heap->pool;
+	pool = work->pool;
 	/* If we make it here we have succeeded in getting fresh work */
-	if (!work_heap->mined) {
+	if (likely(pool)) {
 		pool_tclear(pool, &pool->lagging);
 		if (pool_tclear(pool, &pool->idle))
 			pool_resus(pool);
 	}
 
-	memcpy(work, work_heap, sizeof(*work));
-
-	/* Hand out a clone if we can roll this work item */
-	if (reuse_work(work_heap)) {
-		if (opt_debug)
-			applog(LOG_DEBUG, "Pushing divided work to get queue head");
-
-		stage_work(work_heap);
-		work->clone = true;
-	} else {
-		dec_queued();
-		free_work(work_heap);
-	}
-
-	ret = true;
-out:
-	if (unlikely(ret == false)) {
-		if ((opt_retries >= 0) && (++failures > opt_retries)) {
-			applog(LOG_ERR, "Failed %d times to get_work");
-			return ret;
-		}
-		applog(LOG_DEBUG, "Retrying after %d seconds", fail_pause);
-		sleep(fail_pause);
-		fail_pause += opt_fail_pause;
-		goto retry;
-	}
-	fail_pause = opt_fail_pause;
+	roll_cloned(work);
+	dec_queued();
 
 	work->thr_id = thr_id;
+	work->mined = true;
 	thread_reportin(thr);
-	if (ret)
-		work->mined = true;
-	return ret;
+	return work;
 }
 
 bool submit_work_sync(struct thr_info *thr, const struct work *work_in)
@@ -3211,11 +3202,8 @@ void *miner_thread(void *userdata)
 		work_restart[thr_id].restart = 0;
 		if (api->free_work && likely(work->pool))
 			api->free_work(mythr, work);
-		if (unlikely(!get_work(work, requested, mythr, thr_id))) {
-			applog(LOG_ERR, "work retrieval failed, exiting "
-				"mining thread %d", thr_id);
-			break;
-		}
+		free_work(work);
+		work = get_work(requested, mythr, thr_id);
 		requested = false;
 		cycle = (can_roll(work) && should_roll(work)) ? 1 : def_cycle;
 		gettimeofday(&tv_workstart, NULL);
@@ -3332,7 +3320,7 @@ enum {
 /* Stage another work item from the work returned in a longpoll */
 static void convert_to_work(json_t *val, bool rolltime, struct pool *pool)
 {
-	struct work *work, *work_clone;
+	struct work *work;
 	bool rc;
 
 	work = make_work();
@@ -3350,18 +3338,7 @@ static void convert_to_work(json_t *val, bool rolltime, struct pool *pool)
 	 * allows testwork to know whether LP discovered the block or not. */
 	test_work_current(work, true);
 
-	work_clone = make_work();
-	memcpy(work_clone, work, sizeof(struct work));
-	while (reuse_work(work)) {
-		work_clone->clone = true;
-		if (opt_debug)
-			applog(LOG_DEBUG, "Pushing rolled converted work to stage thread");
-		if (unlikely(!stage_work(work_clone)))
-			break;
-		work_clone = make_work();
-		memcpy(work_clone, work, sizeof(struct work));
-	}
-	free_work(work_clone);
+	roll_cloned(work);
 
 	if (opt_debug)
 		applog(LOG_DEBUG, "Pushing converted work to stage thread");