From: Greg Kroah-Hartman gregkh@linuxfoundation.org
From: Vladimir Oltean vladimir.oltean@nxp.com
commit a74dbce9d4541888fe0d39afe69a3a95004669b4 upstream.
Quoting from the blamed commit:
In promiscuous mode, it is more intuitive that all traffic is received, including VLAN tagged traffic. It appears that it is necessary to set the flag in PSIPVMR for that to be the case, so VLAN promiscuous mode is also temporarily enabled. On exit from promiscuous mode, the setting made by ethtool is restored.
Intuitive or not, there isn't any definition issued by a standards body which says that promiscuity has anything to do with VLAN filtering - it only has to do with accepting packets regardless of destination MAC address.
In fact people are already trying to use this misunderstanding/bug of the enetc driver as a justification to transform promiscuity into something it never was about: accepting every packet (maybe that would be the "rx-all" netdev feature?): https://lore.kernel.org/netdev/20201110153958.ci5ekor3o2ekg3ky@ipetronik.com...
This is relevant because there are use cases in the kernel (such as tc-flower rules with the protocol 802.1Q and a vlan_id key) which do not (yet) use the vlan_vid_add API to be compatible with VLAN-filtering NICs such as enetc, so for those, disabling rx-vlan-filter is currently the only right solution to make these setups work: https://lore.kernel.org/netdev/CA+h21hoxwRdhq4y+w8Kwgm74d4cA0xLeiHTrmT-VpSaM... The blamed patch has unintentionally introduced one more way for this to work, which is to enable IFF_PROMISC, however this is non-portable because port promiscuity is not meant to disable VLAN filtering. Therefore, it could invite people to write broken scripts for enetc, and then wonder why they are broken when migrating to other drivers that don't handle promiscuity in the same way.
Fixes: 7070eea5e95a ("enetc: permit configuration of rx-vlan-filter with ethtool") Cc: Markus Blöchl Markus.Bloechl@ipetronik.com Signed-off-by: Vladimir Oltean vladimir.oltean@nxp.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/ethernet/freescale/enetc/enetc_pf.c | 5 ----- 1 file changed, 5 deletions(-)
--- a/drivers/net/ethernet/freescale/enetc/enetc_pf.c +++ b/drivers/net/ethernet/freescale/enetc/enetc_pf.c @@ -190,7 +190,6 @@ static void enetc_pf_set_rx_mode(struct { struct enetc_ndev_priv *priv = netdev_priv(ndev); struct enetc_pf *pf = enetc_si_priv(priv->si); - char vlan_promisc_simap = pf->vlan_promisc_simap; struct enetc_hw *hw = &priv->si->hw; bool uprom = false, mprom = false; struct enetc_mac_filter *filter; @@ -203,16 +202,12 @@ static void enetc_pf_set_rx_mode(struct psipmr = ENETC_PSIPMR_SET_UP(0) | ENETC_PSIPMR_SET_MP(0); uprom = true; mprom = true; - /* Enable VLAN promiscuous mode for SI0 (PF) */ - vlan_promisc_simap |= BIT(0); } else if (ndev->flags & IFF_ALLMULTI) { /* enable multi cast promisc mode for SI0 (PF) */ psipmr = ENETC_PSIPMR_SET_MP(0); mprom = true; }
- enetc_set_vlan_promisc(&pf->si->hw, vlan_promisc_simap); - /* first 2 filter entries belong to PF */ if (!uprom) { /* Update unicast filters */