[dpdk-dev] [PATCH 2/7] mlx: ensure MTU update is effective

[Nelio Laranjeiro <nelio.laranjeiro@6wind.com>]

From: Adrien Mazarguil <adrien.mazarguil@6wind.com>

There is no guarantee that the new MTU is effective after writing its value
to sysfs. Retrieve it to be sure.

Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
---
 drivers/net/mlx4/mlx4.c        | 10 +++++++++-
 drivers/net/mlx5/mlx5_ethdev.c | 10 +++++++++-
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/net/mlx4/mlx4.c b/drivers/net/mlx4/mlx4.c
index 661c49f..6174e4b 100644
--- a/drivers/net/mlx4/mlx4.c
+++ b/drivers/net/mlx4/mlx4.c
@@ -659,7 +659,15 @@ priv_get_mtu(struct priv *priv, uint16_t *mtu)
 static int
 priv_set_mtu(struct priv *priv, uint16_t mtu)
 {
-	return priv_set_sysfs_ulong(priv, "mtu", mtu);
+	uint16_t new_mtu;
+
+	if (priv_set_sysfs_ulong(priv, "mtu", mtu) ||
+	    priv_get_mtu(priv, &new_mtu))
+		return -1;
+	if (new_mtu == mtu)
+		return 0;
+	errno = EINVAL;
+	return -1;
 }
 
 /**
diff --git a/drivers/net/mlx5/mlx5_ethdev.c b/drivers/net/mlx5/mlx5_ethdev.c
index 36b369e..25926cb 100644
--- a/drivers/net/mlx5/mlx5_ethdev.c
+++ b/drivers/net/mlx5/mlx5_ethdev.c
@@ -398,7 +398,15 @@ priv_get_mtu(struct priv *priv, uint16_t *mtu)
 static int
 priv_set_mtu(struct priv *priv, uint16_t mtu)
 {
-	return priv_set_sysfs_ulong(priv, "mtu", mtu);
+	uint16_t new_mtu;
+
+	if (priv_set_sysfs_ulong(priv, "mtu", mtu) ||
+	    priv_get_mtu(priv, &new_mtu))
+		return -1;
+	if (new_mtu == mtu)
+		return 0;
+	errno = EINVAL;
+	return -1;
 }
 
 /**
-- 
2.1.4