[dpdk-stable] [PATCH] net/e1000: remove MTU setting limitation

[dapengx.yu at intel.com]

From: Dapeng Yu <dapengx.yu at intel.com>

Currently, if requested MTU is bigger than mbuf size and scattered
receive is not enabled, setting MTU to that value fails.

This patch allows setting this special MTU when device is stopped,
because scattered_rx will be re-configured during next port start
and driver may enable scattered receive according new MTU value.

After this patch, driver may select different receive function
automatically after MTU set, according MTU values selected.

Fixes: 59d0ecdbf0e1 ("ethdev: MTU accessors")
Cc: stable at dpdk.org

Signed-off-by: Dapeng Yu <dapengx.yu at intel.com>
---
 drivers/net/e1000/em_ethdev.c  | 12 ++++++++----
 drivers/net/e1000/igb_ethdev.c | 12 ++++++++----
 2 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/drivers/net/e1000/em_ethdev.c b/drivers/net/e1000/em_ethdev.c
index 9b8c4a7de..3c6f643c1 100644
--- a/drivers/net/e1000/em_ethdev.c
+++ b/drivers/net/e1000/em_ethdev.c
@@ -1805,11 +1805,15 @@ eth_em_mtu_set(struct rte_eth_dev *dev, uint16_t mtu)
 	if (mtu < RTE_ETHER_MIN_MTU || frame_size > dev_info.max_rx_pktlen)
 		return -EINVAL;
 
-	/* refuse mtu that requires the support of scattered packets when this
-	 * feature has not been enabled before. */
-	if (!dev->data->scattered_rx &&
-	    frame_size > dev->data->min_rx_buf_size - RTE_PKTMBUF_HEADROOM)
+	/*
+	 * If device is started, refuse mtu that requires the support of
+	 * scattered packets when this feature has not been enabled before.
+	 */
+	if (dev->data->dev_started && !dev->data->scattered_rx &&
+	    frame_size > dev->data->min_rx_buf_size - RTE_PKTMBUF_HEADROOM) {
+		PMD_INIT_LOG(ERR, "Stop port first.");
 		return -EINVAL;
+	}
 
 	hw = E1000_DEV_PRIVATE_TO_HW(dev->data->dev_private);
 	rctl = E1000_READ_REG(hw, E1000_RCTL);
diff --git a/drivers/net/e1000/igb_ethdev.c b/drivers/net/e1000/igb_ethdev.c
index 5323504e9..1716d6b90 100644
--- a/drivers/net/e1000/igb_ethdev.c
+++ b/drivers/net/e1000/igb_ethdev.c
@@ -4394,11 +4394,15 @@ eth_igb_mtu_set(struct rte_eth_dev *dev, uint16_t mtu)
 			frame_size > dev_info.max_rx_pktlen)
 		return -EINVAL;
 
-	/* refuse mtu that requires the support of scattered packets when this
-	 * feature has not been enabled before. */
-	if (!dev->data->scattered_rx &&
-	    frame_size > dev->data->min_rx_buf_size - RTE_PKTMBUF_HEADROOM)
+	/*
+	 * If device is started, refuse mtu that requires the support of
+	 * scattered packets when this feature has not been enabled before.
+	 */
+	if (dev->data->dev_started && !dev->data->scattered_rx &&
+	    frame_size > dev->data->min_rx_buf_size - RTE_PKTMBUF_HEADROOM) {
+		PMD_INIT_LOG(ERR, "Stop port first.");
 		return -EINVAL;
+	}
 
 	rctl = E1000_READ_REG(hw, E1000_RCTL);
 
-- 
2.27.0