[PATCH v2] examples: fix typdef in performance thread app

[David Hunt <david.hunt@intel.com>]

The function pthread_create() expects void *(*func) (void *)
for function pointer, however, lthread_func_t was defined as
void (*func) (void *), so now gcc 8.1 warns that the cast is
incorrect, causing a compilation failure. This patch changes
the declaration of lthread_func_t from returning a void to
returning a void*, and then changes the sample app in the
relevant places that are affected by the typedef change.

Fixes: 116819b9ed0d ("examples/performance-thread: add lthread subsystem")

Signed-off-by: David Hunt <david.hunt@intel.com>
Acked-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>

---
Changes in v2
   1. Removed a couple of un-needed function declarations
      (they are now static).
   2. Ensure each thread returns something (i.e. NULL) nows
      that their declarations have changed to returning void *.
---
 examples/performance-thread/common/lthread.c  |  3 ++-
 .../performance-thread/common/lthread_api.h   |  2 +-
 .../performance-thread/l3fwd-thread/main.c    | 20 ++++++++++++-------
 .../performance-thread/pthread_shim/main.c    |  6 ++----
 .../pthread_shim/pthread_shim.c               |  4 ++--
 5 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/examples/performance-thread/common/lthread.c b/examples/performance-thread/common/lthread.c
index 7d76c8c46..0b60a42a8 100644
--- a/examples/performance-thread/common/lthread.c
+++ b/examples/performance-thread/common/lthread.c
@@ -320,13 +320,14 @@ struct lthread *lthread_current(void)
 /*
  * Tasklet to cancel a thread
  */
-static void
+static void *
 _cancel(void *arg)
 {
 	struct lthread *lt = (struct lthread *) arg;
 
 	lt->state |= BIT(ST_LT_CANCELLED);
 	lthread_detach();
+	return NULL;
 }
 
 
diff --git a/examples/performance-thread/common/lthread_api.h b/examples/performance-thread/common/lthread_api.h
index ff245a082..a74680bf7 100644
--- a/examples/performance-thread/common/lthread_api.h
+++ b/examples/performance-thread/common/lthread_api.h
@@ -143,7 +143,7 @@ struct lthread_mutex;
 struct lthread_condattr;
 struct lthread_mutexattr;
 
-typedef void (*lthread_func_t) (void *);
+typedef void *(*lthread_func_t) (void *);
 
 /*
  * Define the size of stack for an lthread
diff --git a/examples/performance-thread/l3fwd-thread/main.c b/examples/performance-thread/l3fwd-thread/main.c
index f51e6b0fd..40d807239 100644
--- a/examples/performance-thread/l3fwd-thread/main.c
+++ b/examples/performance-thread/l3fwd-thread/main.c
@@ -1990,17 +1990,18 @@ cpu_load_collector(__rte_unused void *arg) {
  *
  * This loop is used to start empty scheduler on lcore.
  */
-static void
+static void *
 lthread_null(__rte_unused void *args)
 {
 	int lcore_id = rte_lcore_id();
 
 	RTE_LOG(INFO, L3FWD, "Starting scheduler on lcore %d.\n", lcore_id);
 	lthread_exit(NULL);
+	return NULL;
 }
 
 /* main processing loop */
-static void
+static void *
 lthread_tx_per_ring(void *dummy)
 {
 	int nb_rx;
@@ -2045,6 +2046,7 @@ lthread_tx_per_ring(void *dummy)
 			lthread_cond_wait(ready, 0);
 
 	}
+	return NULL;
 }
 
 /*
@@ -2053,7 +2055,7 @@ lthread_tx_per_ring(void *dummy)
  * This lthread is used to spawn one new lthread per ring from producers.
  *
  */
-static void
+static void *
 lthread_tx(void *args)
 {
 	struct lthread *lt;
@@ -2098,9 +2100,10 @@ lthread_tx(void *args)
 		}
 
 	}
+	return NULL;
 }
 
-static void
+static void *
 lthread_rx(void *dummy)
 {
 	int ret;
@@ -2124,7 +2127,7 @@ lthread_rx(void *dummy)
 
 	if (rx_conf->n_rx_queue == 0) {
 		RTE_LOG(INFO, L3FWD, "lcore %u has nothing to do\n", rte_lcore_id());
-		return;
+		return NULL;
 	}
 
 	RTE_LOG(INFO, L3FWD, "Entering main Rx loop on lcore %u\n", rte_lcore_id());
@@ -2196,6 +2199,7 @@ lthread_rx(void *dummy)
 			lthread_yield();
 		}
 	}
+	return NULL;
 }
 
 /*
@@ -2204,8 +2208,9 @@ lthread_rx(void *dummy)
  * This lthread loop spawns all rx and tx lthreads on master lcore
  */
 
-static void
-lthread_spawner(__rte_unused void *arg) {
+static void *
+lthread_spawner(__rte_unused void *arg)
+{
 	struct lthread *lt[MAX_THREAD];
 	int i;
 	int n_thread = 0;
@@ -2246,6 +2251,7 @@ lthread_spawner(__rte_unused void *arg) {
 	for (i = 0; i < n_thread; i++)
 		lthread_join(lt[i], NULL);
 
+	return NULL;
 }
 
 /*
diff --git a/examples/performance-thread/pthread_shim/main.c b/examples/performance-thread/pthread_shim/main.c
index 964ea252d..7d0d58116 100644
--- a/examples/performance-thread/pthread_shim/main.c
+++ b/examples/performance-thread/pthread_shim/main.c
@@ -119,8 +119,7 @@ void *helloworld_pthread(void *arg)
  */
 __thread pthread_t tid[HELLOW_WORLD_MAX_LTHREADS];
 
-static void initial_lthread(void *args);
-static void initial_lthread(void *args __attribute__((unused)))
+static void *initial_lthread(void *args __attribute__((unused)))
 {
 	int lcore = (int) rte_lcore_id();
 	/*
@@ -195,6 +194,7 @@ static void initial_lthread(void *args __attribute__((unused)))
 	/* shutdown the lthread scheduler */
 	lthread_scheduler_shutdown(rte_lcore_id());
 	lthread_detach();
+	return NULL;
 }
 
 
@@ -205,8 +205,6 @@ static void initial_lthread(void *args __attribute__((unused)))
  * in the core mask
  */
 static int
-lthread_scheduler(void *args);
-static int
 lthread_scheduler(void *args __attribute__((unused)))
 {
 	/* create initial thread  */
diff --git a/examples/performance-thread/pthread_shim/pthread_shim.c b/examples/performance-thread/pthread_shim/pthread_shim.c
index c31de4e9d..53f12437f 100644
--- a/examples/performance-thread/pthread_shim/pthread_shim.c
+++ b/examples/performance-thread/pthread_shim/pthread_shim.c
@@ -365,7 +365,7 @@ int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
 int
 pthread_create(pthread_t *__restrict tid,
 		const pthread_attr_t *__restrict attr,
-		void *(func) (void *),
+		lthread_func_t func,
 	       void *__restrict arg)
 {
 	if (override) {
@@ -390,7 +390,7 @@ pthread_create(pthread_t *__restrict tid,
 			}
 		}
 		return lthread_create((struct lthread **)tid, lcore,
-				      (void (*)(void *))func, arg);
+				      func, arg);
 	}
 	return _sys_pthread_funcs.f_pthread_create(tid, attr, func, arg);
 }
-- 
2.17.0