[PATCH 2/2] rte_ethdev: add return status for rte_eth_stats_get

[Jia Yu <jyu-pghWNbHTmq7QT0dZR+AlfA@public.gmane.org>]

rte_eth_stats_get is to get physical device statistics. Without
return status, caller does not know whether function fails or not
(i.e. invalid port_id, driver has no stats_get callback). Caller
cannot differiente normal 0 stats or error case. This fix adds
a return status to the function.

Signed-off-by: Jia Yu <jyu-pghWNbHTmq7QT0dZR+AlfA@public.gmane.org>
---
 lib/librte_ether/rte_ethdev.c | 7 ++++---
 lib/librte_ether/rte_ethdev.h | 4 +++-
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c
index 6c01b02..4ec9ca6 100644
--- a/lib/librte_ether/rte_ethdev.c
+++ b/lib/librte_ether/rte_ethdev.c
@@ -1226,21 +1226,22 @@ rte_eth_link_get_nowait(uint8_t port_id, struct rte_eth_link *eth_link)
 	}
 }
 
-void
+int
 rte_eth_stats_get(uint8_t port_id, struct rte_eth_stats *stats)
 {
 	struct rte_eth_dev *dev;
 
 	if (port_id >= nb_ports) {
 		PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
-		return;
+		return (-ENODEV);
 	}
 	dev = &rte_eth_devices[port_id];
 	memset(stats, 0, sizeof(*stats));
 
-	FUNC_PTR_OR_RET(*dev->dev_ops->stats_get);
+	FUNC_PTR_OR_ERR_RET(*dev->dev_ops->stats_get, -ENOTSUP);
 	(*dev->dev_ops->stats_get)(dev, stats);
 	stats->rx_nombuf = dev->data->rx_mbuf_alloc_failed;
+        return 0;
 }
 
 void
diff --git a/lib/librte_ether/rte_ethdev.h b/lib/librte_ether/rte_ethdev.h
index 8bf274d..e29e9be 100644
--- a/lib/librte_ether/rte_ethdev.h
+++ b/lib/librte_ether/rte_ethdev.h
@@ -2054,8 +2054,10 @@ extern void rte_eth_link_get_nowait(uint8_t port_id,
  *   - *obytes*   with the total of successfully transmitted bytes.
  *   - *ierrors*  with the total of erroneous received packets.
  *   - *oerrors*  with the total of failed transmitted packets.
+ * @return
+ *   Zero if successful. Non-zero otherwise.
  */
-extern void rte_eth_stats_get(uint8_t port_id, struct rte_eth_stats *stats);
+extern int rte_eth_stats_get(uint8_t port_id, struct rte_eth_stats *stats);
 
 /**
  * Reset the general I/O statistics of an Ethernet device.
-- 
1.9.1