cxgbe: fix setting wrong MTU

max_rx_pkt_len already includes ETHER_HDR_LEN and ETHER_CRC_LEN for the
mtu. But, the firmware also adds ETHER_HDR_LEN and ETHER_CRC_LEN to the
mtu specified. Fix by subtracting these values from the mtu before
passing it to firmware.

Fixes: 4b2eff452d2e ("cxgbe: enable jumbo frames")

Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
Signed-off-by: Kumar Sanghvi <kumaras@chelsio.com>

diff --git a/doc/guides/rel_notes/release_16_04.rst b/doc/guides/rel_notes/release_16_04.rst
index 4abe246..36f7e37 100644 (file)
--- a/doc/guides/rel_notes/release_16_04.rst
+++ b/doc/guides/rel_notes/release_16_04.rst
@@ -162,6 +162,11 @@ Drivers
   table that gets overwritten by subsequent port 1's part of the RSS
   table due to incorrect size allocated for each entry in the table.
 
+* **cxgbe: Fixed setting wrong device MTU.**
+
+  Fixed an incorrect device MTU being set due to ethernet header and
+  CRC lengths being added twice.
+
 * **aesni_mb: Fixed wrong return value when creating a device.**
 
   cryptodev_aesni_mb_init() was returning the device id of the device created,

diff --git a/drivers/net/cxgbe/cxgbe_main.c b/drivers/net/cxgbe/cxgbe_main.c
index 552b11f..684a761 100644 (file)
--- a/drivers/net/cxgbe/cxgbe_main.c
+++ b/drivers/net/cxgbe/cxgbe_main.c
@@ -855,7 +855,10 @@ int link_start(struct port_info *pi)
 {
        struct adapter *adapter = pi->adapter;
        int ret;
-       unsigned int mtu = pi->eth_dev->data->dev_conf.rxmode.max_rx_pkt_len;
+       unsigned int mtu;
+
+       mtu = pi->eth_dev->data->dev_conf.rxmode.max_rx_pkt_len -
+             (ETHER_HDR_LEN + ETHER_CRC_LEN);
 
        /*
         * We do not set address filters and promiscuity here, the stack does