diff options
| author | Clemens Gruber <mail@clemensgruber.at> | 2026-01-21 11:37:51 +0300 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2026-01-22 15:21:19 +0300 |
| commit | ca1bb3fedf26a08ed31974131bc0064d4fe33649 (patch) | |
| tree | 110161c23ff432cabc16a81b7814aefe3aa72ad3 | |
| parent | cc4816bdb08639e5cd9acb295a02d6f0f09736b4 (diff) | |
| download | linux-ca1bb3fedf26a08ed31974131bc0064d4fe33649.tar.xz | |
net: fec: account for VLAN header in frame length calculations
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: 62b5bb7be7bc ("net: fec: update MAX_FL based on the current MTU")
Fixes: d466c16026e9 ("net: fec: enable the Jumbo frame support for i.MX8QM")
Fixes: 59e9bf037d75 ("net: fec: add change_mtu to support dynamic buffer allocation")
Fixes: ec2a1681ed4f ("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>
| -rw-r--r-- | drivers/net/ethernet/freescale/fec_main.c | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c index a753265961af..797ef6899657 100644 --- a/drivers/net/ethernet/freescale/fec_main.c +++ b/drivers/net/ethernet/freescale/fec_main.c @@ -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) |