6.6-stable review patch. If anyone has any objections, please let me know.
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From: Wei Fang wei.fang@nxp.com
[ Upstream commit 2939203ffee818f1e5ebd60bbb85a174d63aab9c ]
In the current implementation, the enetc_xdp_xmit() always transmits redirected XDP frames even if the link is down, but the frames cannot be transmitted from TX BD rings when the link is down, so the frames are still kept in the TX BD rings. If the XDP program is uninstalled, users will see the following warning logs.
fsl_enetc 0000:00:00.0 eno0: timeout for tx ring #6 clear
More worse, the TX BD ring cannot work properly anymore, because the HW PIR and CIR are not equal after the re-initialization of the TX BD ring. At this point, the BDs between CIR and PIR are invalid, which will cause a hardware malfunction.
Another reason is that there is internal context in the ring prefetch logic that will retain the state from the first incarnation of the ring and continue prefetching from the stale location when we re-initialize the ring. The internal context is only reset by an FLR. That is to say, for LS1028A ENETC, software cannot set the HW CIR and PIR when initializing the TX BD ring.
It does not make sense to transmit redirected XDP frames when the link is down. Add a link status check to prevent transmission in this condition. This fixes part of the issue, but more complex cases remain. For example, the TX BD ring may still contain unsent frames when the link goes down. Those situations require additional patches, which will build on this one.
Fixes: 9d2b68cc108d ("net: enetc: add support for XDP_REDIRECT") Signed-off-by: Wei Fang wei.fang@nxp.com Reviewed-by: Frank Li Frank.Li@nxp.com Reviewed-by: Hariprasad Kelam hkelam@marvell.com Reviewed-by: Vladimir Oltean vladimir.oltean@nxp.com Link: https://patch.msgid.link/20251211020919.121113-1-wei.fang@nxp.com Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/freescale/enetc/enetc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/freescale/enetc/enetc.c b/drivers/net/ethernet/freescale/enetc/enetc.c index 7accf3a3e9f0d..e3ab6f4f8dbba 100644 --- a/drivers/net/ethernet/freescale/enetc/enetc.c +++ b/drivers/net/ethernet/freescale/enetc/enetc.c @@ -1429,7 +1429,8 @@ int enetc_xdp_xmit(struct net_device *ndev, int num_frames, int xdp_tx_bd_cnt, i, k; int xdp_tx_frm_cnt = 0;
- if (unlikely(test_bit(ENETC_TX_DOWN, &priv->flags))) + if (unlikely(test_bit(ENETC_TX_DOWN, &priv->flags) || + !netif_carrier_ok(ndev))) return -ENETDOWN;
enetc_lock_mdio();