From dc8fcb26807c734cf79d8a82d2ba655f226ad135 Mon Sep 17 00:00:00 2001
From: Frederic Robra
Date: Wed, 4 Sep 2019 15:10:03 +0200
Subject: prepared kernel module to have configurable number of connections

---
 src/kernel/net.c | 55 ++++++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 42 insertions(+), 13 deletions(-)

(limited to 'src/kernel/net.c')

diff --git a/src/kernel/net.c b/src/kernel/net.c
index f4665bf..061deb1 100644
--- a/src/kernel/net.c
+++ b/src/kernel/net.c
@@ -73,7 +73,7 @@ static void dnbd3_timer(struct timer_list *arg)
 	busy = dnbd3_is_mq_busy(dev);
 
 	if (dev->timer_count % TIMER_INTERVAL_KEEPALIVE_PACKET == 0) {
-		for (i = 0; i < NUMBER_CONNECTIONS; i++) {
+		for (i = 0; i < dev->number_connections; i++) {
 			if (!test_bit(i, &busy) && dnbd3_is_sock_alive(dev->socks[i])) {
 				queue_work(dnbd3_wq, &dev->socks[i].keepalive_worker);
 			}
@@ -294,7 +294,7 @@ static int dnbd3_compare_plan(const void *lhs, const void *rhs)
 static void dnbd3_lock_all_socks(struct dnbd3_device *dev)
 {
 	int i;
-	for (i = 0; i < NUMBER_CONNECTIONS; i++) {
+	for (i = 0; i < dev->number_connections; i++) {
 		mutex_lock(&dev->socks[i].tx_lock);
 	}
 }
@@ -302,7 +302,7 @@ static void dnbd3_lock_all_socks(struct dnbd3_device *dev)
 static void dnbd3_unlock_all_socks(struct dnbd3_device *dev)
 {
 	int i;
-	for (i = 0; i < NUMBER_CONNECTIONS; i++) {
+	for (i = 0; i < dev->number_connections; i++) {
 		mutex_unlock(&dev->socks[i].tx_lock);
 	}
 }
@@ -312,7 +312,7 @@ static void dnbd3_print_conenction_plan(struct dnbd3_device *dev,
 {
 	int i;
 	debug_dev(dev, "connection plan:");
-	for (i = 0; i < NUMBER_CONNECTIONS; i++) {
+	for (i = 0; i < dev->number_connections; i++) {
 		debug_server(dev, plan[i], "server %d with avg rtt %llu:",
 				i, plan[i]->avg_rtt);
 	}
@@ -328,14 +328,20 @@ static void dnbd3_print_conenction_plan(struct dnbd3_device *dev,
  */
 static int dnbd3_adjust_connections(struct dnbd3_device *dev) {
 	int i, j, fallback, alive;
-	struct dnbd3_server *plan[NUMBER_CONNECTIONS];
+	struct dnbd3_server **plan;
 	struct dnbd3_server **servers = dnbd3_sort_server(dev);
 
+	plan = kmalloc(sizeof(struct dnbd3_server *) * dev->number_connections,
+			GFP_KERNEL);
+	if (!plan) {
+		error_dev(dev, "kmalloc failed");
+	}
+
 	if (servers && servers[0]->host.type != 0) {
 		plan[0] = servers[0];
 		fallback = 0;
 		j = 1;
-		for (i = 1; i < NUMBER_CONNECTIONS; i++) {
+		for (i = 1; i < dev->number_connections; i++) {
 			if (servers[j]->host.type != 0 &&
 					servers[j]->avg_rtt < RTT_UNKNOWN) {
 				if (RTT_FACTOR(plan[i - 1]->avg_rtt) >
@@ -353,13 +359,13 @@ static int dnbd3_adjust_connections(struct dnbd3_device *dev) {
 		}
 		kfree(servers);
 
-		sort(plan, NUMBER_CONNECTIONS, sizeof(struct dnbd3_server *),
+		sort(plan, dev->number_connections, sizeof(struct dnbd3_server *),
 			&dnbd3_compare_plan, NULL);
 		dnbd3_print_conenction_plan(dev, plan);
 
 		dnbd3_lock_all_socks(dev);
 		alive = 0;
-		for (i = 0; i < NUMBER_CONNECTIONS; i++) {
+		for (i = 0; i < dev->number_connections; i++) {
 			if (plan[i] != dev->socks[i].server ||
 					!dnbd3_is_sock_alive(dev->socks[i])) {
 
@@ -405,7 +411,7 @@ static void dnbd3_panic_worker(struct work_struct *work)
 	int i;
 	int sock_alive = 0;
 	dev = container_of(work, struct dnbd3_device, panic_worker);
-	for (i = 0; i < NUMBER_CONNECTIONS; i++) {
+	for (i = 0; i < dev->number_connections; i++) {
 		if (!dnbd3_is_sock_alive(dev->socks[i])
 				|| dev->socks[i].server->failures > 1000) {
 			panic = true;
@@ -445,7 +451,7 @@ static int dnbd3_meassure_rtt(struct dnbd3_device *dev,
 	int result;
 	uint64_t rtt = RTT_UNREACHABLE;
 	struct dnbd3_sock sock = {
-			.sock_nr = NUMBER_CONNECTIONS,
+			.sock_nr = dev->number_connections,
 			.sock = NULL,
 			.device = dev,
 			.server = server
@@ -505,11 +511,13 @@ static int dnbd3_meassure_rtt(struct dnbd3_device *dev,
 	rtt = (uint64_t)((end.tv_sec - start.tv_sec) * 1000000ull
 			+ (end.tv_usec - start.tv_usec));
 
-	debug_sock(&sock, "new rrt is %llu", rtt);
 
 error:
 	sock.server->rtts[dev->discovery_count % 4] = rtt;
 	sock.server->avg_rtt = dnbd3_average_rtt(sock.server);
+
+	debug_sock(&sock, "meassured rrt: %llu; avg_rtt: %llu", rtt,
+			sock.server->avg_rtt);
 	if (result <= 0) {
 		server->failures++;
 	}
@@ -846,8 +854,22 @@ static int dnbd3_socket_disconnect(struct dnbd3_sock *sock)
  */
 int dnbd3_net_connect(struct dnbd3_device *dev)
 {
-	int result;
+	int i, result;
 	debug_dev(dev, "connecting to server");
+	dev->socks = kmalloc(sizeof(struct dnbd3_sock) *
+			dev->number_connections, GFP_KERNEL);
+	if (!dev->socks) {
+		error_dev(dev, "kmalloc failed");
+	}
+	memset(dev->socks, 0, sizeof(struct dnbd3_sock) *
+			dev->number_connections);
+	for (i = 0; i < dev->number_connections; i++) {
+		dev->socks[i].device = dev;
+		dev->socks[i].sock_nr = i;
+		mutex_init(&dev->socks[i].tx_lock);
+	}
+	debug_dev(dev, "set nr hw queues to %d", dev->number_connections);
+	blk_mq_update_nr_hw_queues(&dev->tag_set, dev->number_connections);
 
 	if (dev->alt_servers[0].host.type == 0) {
 		return -ENONET;
@@ -888,19 +910,26 @@ int dnbd3_net_disconnect(struct dnbd3_device *dev)
 	int i;
 	int result = 0;
 
+	if (!dev->socks) {
+		info_dev(dev, "not connected");
+	}
+
 	del_timer_sync(&dev->timer);
 	/* be sure it does not recover while disconnecting */
 	cancel_work_sync(&dev->discovery_worker);
 	cancel_work_sync(&dev->panic_worker);
-	for (i = 0; i < NUMBER_CONNECTIONS; i++) {
+	for (i = 0; i < dev->number_connections; i++) {
 		if (dev->socks[i].sock) {
 			mutex_lock(&dev->socks[i].tx_lock);
 			if (dnbd3_socket_disconnect(&dev->socks[i])) {
 				result = -EIO;
 			}
 			mutex_unlock(&dev->socks[i].tx_lock);
+			mutex_destroy(&dev->socks[i].tx_lock);
 		}
 	}
+	kfree(dev->socks);
+	dev->socks = NULL;
 	dev->connected = false;
 	return result;
 }
-- 
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