> -----Original Message-----
> From: Intel-wired-lan <[email protected]> On Behalf
> Of Ding Meng via Intel-wired-lan
> Sent: Monday, June 22, 2026 6:13 AM
> To: Nguyen, Anthony L <[email protected]>; Kitszel,
> Przemyslaw <[email protected]>; [email protected];
> [email protected]; [email protected]; [email protected];
> [email protected]; Kiszka, Jan <[email protected]>; Bezdeka,
> Florian <[email protected]>
> Cc: [email protected]; [email protected];
> [email protected]; [email protected]; [email protected]
> Subject: [Intel-wired-lan] [PATCH net] igc: Fix RX HW timestamp
> reporting when NET_RX_BUSY_POLL is disabled
>
> When CONFIG_NET_RX_BUSY_POLL is deactivated, fetching RX HW timestamps
> from the NIC no longer works as expected.
>
> This occurs because disabling CONFIG_NET_RX_BUSY_POLL disables the SKB
> NAPI mapping in __skb_mark_napi_id(). Consequently, get_timestamp()
> fails to perform its driver lookup, and the igc driver's struct
> net_device_ops::ndo_get_tstamp is never invoked.
>
> Instead, get_timestamp() falls back to use shhwtstamps(skb)->hwtstamp,
> a field that the driver has not populated.
>
> Fix this by populating the hwtstamp field with the correct timestamp
> in the default timer when CONFIG_NET_RX_BUSY_POLL is disabled.
>
> Fixes: 069b142f5819 ("igc: Add support for PTP .getcyclesx64()")
I think, because it's a fix, it needs Cc: [email protected]
Reviewed-by: Aleksandr Loktionov <[email protected]>
> Co-developed-by: Florian Bezdeka <[email protected]>
> Signed-off-by: Florian Bezdeka <[email protected]>
> Signed-off-by: Ding Meng <[email protected]>
> ---
> drivers/net/ethernet/intel/igc/igc_main.c | 38 ++++++++++++++++------
> -
> 1 file changed, 26 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/igc/igc_main.c
> b/drivers/net/ethernet/intel/igc/igc_main.c
> index 8ac16808023..1da8d7aa76d 100644
> --- a/drivers/net/ethernet/intel/igc/igc_main.c
> +++ b/drivers/net/ethernet/intel/igc/igc_main.c
> @@ -1992,7 +1992,26 @@ static struct sk_buff *igc_build_skb(struct
> igc_ring *rx_ring,
> return skb;
> }
>
> -static struct sk_buff *igc_construct_skb(struct igc_ring *rx_ring,
> +static void igc_construct_skb_timestamps(struct igc_adapter *adapter,
> + struct sk_buff *skb,
> + struct igc_xdp_buff *ctx)
> +{
> + if (!ctx->rx_ts)
> + return;
> +#ifdef CONFIG_NET_RX_BUSY_POLL
> + skb_shinfo(skb)->tx_flags |= SKBTX_HW_TSTAMP_NETDEV;
> + skb_hwtstamps(skb)->netdev_data = ctx->rx_ts; #else
> + struct igc_inline_rx_tstamps *tstamps;
> +
> + tstamps = ctx->rx_ts;
> + skb_hwtstamps(skb)->hwtstamp = igc_ptp_rx_pktstamp(adapter,
> + tstamps->timer0);
> +#endif
> +}
> +
> +static struct sk_buff *igc_construct_skb(struct igc_adapter *adapter,
> + struct igc_ring *rx_ring,
> struct igc_rx_buffer *rx_buffer,
> struct igc_xdp_buff *ctx)
> {
> @@ -2013,10 +2032,7 @@ static struct sk_buff *igc_construct_skb(struct
> igc_ring *rx_ring,
> if (unlikely(!skb))
> return NULL;
>
> - if (ctx->rx_ts) {
> - skb_shinfo(skb)->tx_flags |= SKBTX_HW_TSTAMP_NETDEV;
> - skb_hwtstamps(skb)->netdev_data = ctx->rx_ts;
> - }
> + igc_construct_skb_timestamps(adapter, skb, ctx);
>
> /* Determine available headroom for copy */
> headlen = size;
> @@ -2686,7 +2702,7 @@ static int igc_clean_rx_irq(struct igc_q_vector
> *q_vector, const int budget)
> else if (ring_uses_build_skb(rx_ring))
> skb = igc_build_skb(rx_ring, rx_buffer,
> &ctx.xdp);
> else
> - skb = igc_construct_skb(rx_ring, rx_buffer,
> &ctx);
> + skb = igc_construct_skb(adapter, rx_ring,
> rx_buffer, &ctx);
>
> /* exit if we failed to retrieve a buffer */
> if (!xdp_res && !skb) {
> @@ -2738,7 +2754,8 @@ static int igc_clean_rx_irq(struct igc_q_vector
> *q_vector, const int budget)
> return total_packets;
> }
>
> -static struct sk_buff *igc_construct_skb_zc(struct igc_ring *ring,
> +static struct sk_buff *igc_construct_skb_zc(struct igc_adapter
> *adapter,
> + struct igc_ring *ring,
> struct igc_xdp_buff *ctx)
> {
> struct xdp_buff *xdp = &ctx->xdp;
> @@ -2760,10 +2777,7 @@ static struct sk_buff
> *igc_construct_skb_zc(struct igc_ring *ring,
> __skb_pull(skb, metasize);
> }
>
> - if (ctx->rx_ts) {
> - skb_shinfo(skb)->tx_flags |= SKBTX_HW_TSTAMP_NETDEV;
> - skb_hwtstamps(skb)->netdev_data = ctx->rx_ts;
> - }
> + igc_construct_skb_timestamps(adapter, skb, ctx);
>
> return skb;
> }
> @@ -2775,7 +2789,7 @@ static void igc_dispatch_skb_zc(struct
> igc_q_vector *q_vector,
> struct igc_ring *ring = q_vector->rx.ring;
> struct sk_buff *skb;
>
> - skb = igc_construct_skb_zc(ring, ctx);
> + skb = igc_construct_skb_zc(q_vector->adapter, ring, ctx);
> if (!skb) {
> ring->rx_stats.alloc_failed++;
> set_bit(IGC_RING_FLAG_RX_ALLOC_FAILED, &ring->flags);
>
> base-commit: 4549871118cf616eecdd2d939f78e3b9e1dddc48
> --
> 2.47.3
