>-----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()")
>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;
Please move at the top of the function and add:
Reviewed-by: Piotr Kwapulinski <[email protected]
>+
>+ 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
>
>
