github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-07-28 01:55:51 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

net: fec: account for VLAN header in frame length calculations

Browse Source 
The MAX_FL (maximum frame length) and related calculations used ETH_HLEN,
which does not account for the 4-byte VLAN tag in tagged frames. This
caused the hardware to reject valid VLAN frames as oversized, resulting
in RX errors and dropped packets.

Use VLAN_ETH_HLEN instead of ETH_HLEN in the MAX_FL register setup,
cut-through mode threshold, buffer allocation, and max_mtu calculation.

Cc: stable@kernel.org # v6.18+
Fixes: 62b5bb7be7 ("net: fec: update MAX_FL based on the current MTU")
Fixes: d466c16026 ("net: fec: enable the Jumbo frame support for i.MX8QM")
Fixes: 59e9bf037d ("net: fec: add change_mtu to support dynamic buffer allocation")
Fixes: ec2a1681ed ("net: fec: use a member variable for maximum buffer size")
Signed-off-by: Clemens Gruber <mail@clemensgruber.at>
Reviewed-by: Wei Fang <wei.fang@nxp.com>
Link: https://patch.msgid.link/20260121083751.66997-1-mail@clemensgruber.at
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Clemens Gruber 2026-01-21 09:37:51 +01:00 committed by Paolo Abeni
parent cc4816bdb0
commit ca1bb3fedf
1 changed files with 7 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
drivers/net/ethernet/freescale/fec_main.c
View File

@ -1150,7 +1150,7 @@ fec_restart(struct net_device *ndev)
u32 rcntl = FEC_RCR_MII;
if (OPT_ARCH_HAS_MAX_FL)
rcntl |= (fep->netdev->mtu + ETH_HLEN + ETH_FCS_LEN) << 16;
rcntl |= (fep->netdev->mtu + VLAN_ETH_HLEN + ETH_FCS_LEN) << 16;
if (fep->bufdesc_ex)
fec_ptp_save_state(fep);
@ -1285,12 +1285,13 @@ fec_restart(struct net_device *ndev)
/* When Jumbo Frame is enabled, the FIFO may not be large enough
* to hold an entire frame. In such cases, if the MTU exceeds
* (PKT_MAXBUF_SIZE - ETH_HLEN - ETH_FCS_LEN), configure the interface
* to operate in cut-through mode, triggered by the FIFO threshold.
* (PKT_MAXBUF_SIZE - VLAN_ETH_HLEN - ETH_FCS_LEN), configure
* the interface to operate in cut-through mode, triggered by
* the FIFO threshold.
* Otherwise, enable the ENET store-and-forward mode.
*/
if ((fep->quirks & FEC_QUIRK_JUMBO_FRAME) &&
(ndev->mtu > (PKT_MAXBUF_SIZE - ETH_HLEN - ETH_FCS_LEN)))
(ndev->mtu > (PKT_MAXBUF_SIZE - VLAN_ETH_HLEN - ETH_FCS_LEN)))
writel(0xF, fep->hwp + FEC_X_WMRK);
else
writel(FEC_TXWMRK_STRFWD, fep->hwp + FEC_X_WMRK);
@ -4037,7 +4038,7 @@ static int fec_change_mtu(struct net_device *ndev, int new_mtu)
if (netif_running(ndev))
return -EBUSY;
order = get_order(new_mtu + ETH_HLEN + ETH_FCS_LEN
order = get_order(new_mtu + VLAN_ETH_HLEN + ETH_FCS_LEN
+ FEC_DRV_RESERVE_SPACE);
fep->rx_frame_size = (PAGE_SIZE << order) - FEC_DRV_RESERVE_SPACE;
fep->pagepool_order = order;
@ -4588,7 +4589,7 @@ fec_probe(struct platform_device *pdev)
else
fep->max_buf_size = PKT_MAXBUF_SIZE;
ndev->max_mtu = fep->max_buf_size - ETH_HLEN - ETH_FCS_LEN;
ndev->max_mtu = fep->max_buf_size - VLAN_ETH_HLEN - ETH_FCS_LEN;
ret = register_netdev(ndev);
if (ret)