ring: improve looping over links

Signed-off-by: Federico Simoncelli <federico.simoncelli@gmail.com>

ring.c

@@ -151,28 +151,34 @@ int knet_host_release(knet_handle_t knet_h)
 	return pthread_rwlock_unlock(&knet_h->list_rwlock);
 }
 
-int knet_link_foreach(knet_handle_t knet_h, knet_link_fn_t linkfn, void *data)
+int knet_link_foreach(struct knet_link_search *data, knet_link_fn_t linkfn)
 {
-	int lockstatus, i;
-	struct knet_host *host;
+	int lockstatus, i, ret;
 
-	lockstatus = pthread_rwlock_tryrdlock(&knet_h->list_rwlock);
+	lockstatus = pthread_rwlock_rdlock(&data->knet_h->list_rwlock);
 
 	if ((lockstatus != 0) && (lockstatus != EDEADLK)) {
 		return -EBUSY;
 	}
 
-	for (host = knet_h->host_head; host != NULL; host = host->next) {
+	data->host = data->knet_h->host_head;
+
+	for (; data->host != NULL; data->host = data->host->next) {
 		for (i = 0; i < KNET_MAX_LINK; i++) {
-			if (host->link[i].ready != 1) continue;
-			if (linkfn(knet_h, host, &host->link[i], data) == 1)
+			if (data->host->link[i].ready != 1) continue;
+
+			ret = linkfn(data, &data->host->link[i]);
+
+			if (ret == KNET_LINK_FOREACH_SKIP)
+				break;
+			else if (ret == KNET_LINK_FOREACH_FOUND)
 				goto exit_unlock;
 		}
 	}
 
  exit_unlock:
 	if (lockstatus == 0)
-		pthread_rwlock_unlock(&knet_h->list_rwlock);
+		pthread_rwlock_unlock(&data->knet_h->list_rwlock);
 
 	return 0;
 }
@@ -314,26 +320,33 @@ int knet_listener_add(knet_handle_t knet_h, struct knet_listener *listener)
 	return -1;
 }
 
+static int check_listener_sock(struct knet_link_search *data, struct knet_link *j)
+{
+	if (j->sock == data->param1) {
+		data->retval = -EBUSY;
+		return KNET_LINK_FOREACH_FOUND;
+	}
+
+	return KNET_LINK_FOREACH_NEXT;
+}
+
 int knet_listener_remove(knet_handle_t knet_h, struct knet_listener *listener)
 {
-	int ret, j;
 	struct epoll_event ev; /* kernel < 2.6.9 bug (see epoll_ctl man) */
 	struct knet_listener *lp;
-	struct knet_host *i;
+	struct knet_link_search check_search;
 
 	if (pthread_rwlock_wrlock(&knet_h->list_rwlock) != 0)
-		return -1;
+		return -EINVAL;
 
-	ret = 0;
+	check_search.knet_h = knet_h;
+	check_search.retval = 0;
+	check_search.param1 = listener->sock;
 
-	for (i = knet_h->host_head; i != NULL; i = i->next) {
-		for (j = 0; j < KNET_MAX_LINK; j++) {
-			if (i->link[j].sock == listener->sock) {
-				errno = ret = EBUSY;
-				goto exit_fail1;
-			}
-		}
-	}
+	knet_link_foreach(&check_search, check_listener_sock);
+
+	if (check_search.retval != 0)
+		goto exit_fail1;
 
 	/* TODO: use a doubly-linked list? */
 	if (listener == knet_h->listener_head) {
@@ -353,7 +366,9 @@ int knet_listener_remove(knet_handle_t knet_h, struct knet_listener *listener)
  exit_fail1:
 	pthread_rwlock_unlock(&knet_h->list_rwlock);
 
-	return (ret > 0) ? -ret : ret;
+	if (check_search.retval != 0) errno = check_search.retval;
+
+	return check_search.retval;
 }
 
 void knet_link_timeout(struct knet_link *lnk,

ring.h

@@ -89,8 +89,20 @@ int knet_host_remove(knet_handle_t khandle, struct knet_host *host);
 
 void knet_link_timeout(struct knet_link *lnk, time_t interval, time_t timeout, int precision);
 
-typedef int (*knet_link_fn_t)(knet_handle_t knet_h, struct knet_host *host, struct knet_link *link, void *data);
-int knet_link_foreach(knet_handle_t knet_h, knet_link_fn_t linkfn, void *data);
+#define KNET_LINK_FOREACH_NEXT 0 /* next link */
+#define KNET_LINK_FOREACH_SKIP 1 /* skip to next host */
+#define KNET_LINK_FOREACH_FOUND 2 /* loop stop */
+
+struct knet_link_search {
+	knet_handle_t knet_h;
+	struct knet_host *host;
+	int param1;
+	int retval;
+	void *data;
+};
+
+typedef int (*knet_link_fn_t)(struct knet_link_search *data, struct knet_link *link);
+int knet_link_foreach(struct knet_link_search *data, knet_link_fn_t linkfn);
 
 int knet_listener_acquire(knet_handle_t knet_h, struct knet_listener **head, int writelock);
 int knet_listener_release(knet_handle_t knet_h);

tests/ping_test.c

@@ -113,11 +113,12 @@ static void argv_to_hosts(int argc, char *argv[])
  *   # tc -d qdisc show dev lo
  *   # tc qdisc del dev lo root
  */
-static int print_link(knet_handle_t handle, struct knet_host *i, struct knet_link *j, void *data)
+static int print_link(struct knet_link_search *data, struct knet_link *j)
 {
-	printf("link %p latency is %llums, status: %s\n",
-		j, j->latency, (j->enabled == 0) ? "disabled" : "enabled");
-	return 0;
+	printf("host %p, link %p latency is %llums, status: %s\n",
+		data->host, j, j->latency, (j->enabled == 0) ? "disabled" : "enabled");
+
+	return KNET_LINK_FOREACH_NEXT;
 }
 
 static void sigint_handler(int signum)
@@ -144,6 +145,7 @@ int main(int argc, char *argv[])
 	size_t len;
 	fd_set rfds;
 	struct timeval tv;
+	struct knet_link_search print_search;
 
 	if (argc < 3) {
 		print_usage(argv[0]);
@@ -167,12 +169,13 @@ int main(int argc, char *argv[])
 		exit(EXIT_FAILURE);
 	}
 
+	print_search.knet_h = knet_h;
+
 	argv_to_hosts(argc, argv);
-
-	knet_handle_setfwd(knet_h, 1);
+	knet_handle_setfwd(knet_h, 1);	
 
 	while (1) {
-		knet_link_foreach(knet_h, print_link, NULL);
+		knet_link_foreach(&print_search, print_link);
 
 		log_info("Sending 'Hello World!' frame");
 		write(knet_sock[1], "Hello World!", 13);