[PATCH 3/4] eventdev: have ethernet Tx adapter appropriately report idle

["Mattias Rönnblom" <mattias.ronnblom@ericsson.com>]

Update the Event Ethernet Tx Adapter's service function to report as
idle (i.e., return -EAGAIN) in case no events were dequeued from the
event device and no Ethernet frames were sent out on the wire.

Signed-off-by: Mattias Rönnblom <mattias.ronnblom@ericsson.com>
---
 lib/eventdev/rte_event_eth_tx_adapter.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/lib/eventdev/rte_event_eth_tx_adapter.c b/lib/eventdev/rte_event_eth_tx_adapter.c
index 7f7d86f683..c2a848103b 100644
--- a/lib/eventdev/rte_event_eth_tx_adapter.c
+++ b/lib/eventdev/rte_event_eth_tx_adapter.c
@@ -639,6 +639,7 @@ txa_service_func(void *args)
 	struct txa_service_data *txa = args;
 	uint8_t dev_id;
 	uint8_t port;
+	int ret = -EAGAIN;
 	uint16_t n;
 	uint32_t nb_tx, max_nb_tx;
 	struct rte_event ev[TXA_BATCH_SIZE];
@@ -648,10 +649,10 @@ txa_service_func(void *args)
 	port = txa->port_id;
 
 	if (txa->nb_queues == 0)
-		return 0;
+		return ret;
 
 	if (!rte_spinlock_trylock(&txa->tx_lock))
-		return 0;
+		return ret;
 
 	for (nb_tx = 0; nb_tx < max_nb_tx; nb_tx += n) {
 
@@ -659,6 +660,7 @@ txa_service_func(void *args)
 		if (!n)
 			break;
 		txa_service_tx(txa, ev, n);
+		ret = 0;
 	}
 
 	if ((txa->loop_cnt++ & (TXA_FLUSH_THRESHOLD - 1)) == 0) {
@@ -692,10 +694,13 @@ txa_service_func(void *args)
 			}
 		}
 
-		txa->stats.tx_packets += nb_tx;
+		if (likely(nb_tx > 0)) {
+			txa->stats.tx_packets += nb_tx;
+			ret = 0;
+		}
 	}
 	rte_spinlock_unlock(&txa->tx_lock);
-	return 0;
+	return ret;
 }
 
 static int
-- 
2.34.1