Re: [RFC bpf-next 02/23] ice: make RX HW timestamp reading code more reusable

Maciej Fijalkowski
2023-09-04T14:57:02Z

On Thu, Aug 24, 2023 at 09:26:41PM +0200, Larysa Zaremba wrote:
> Previously, we only needed RX HW timestamp in skb path,
> hence all related code was written with skb in mind.
> But with the addition of XDP hints via kfuncs to the ice driver,
> the same logic will be needed in .xmo_() callbacks.
>
> Put generic process of reading RX HW timestamp from a descriptor
> into a separate function.
> Move skb-related code into another source file.
>
> Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
> ---
> drivers/net/ethernet/intel/ice/ice_ptp.c | 24 ++++++------------
> drivers/net/ethernet/intel/ice/ice_ptp.h | 15 ++++++-----
> drivers/net/ethernet/intel/ice/ice_txrx_lib.c | 25 ++++++++++++++++++-
> 3 files changed, 41 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/ice/ice_ptp.c b/drivers/net/ethernet/intel/ice/ice_ptp.c
> index 81d96a40d5a7..a31333972c68 100644
> --- a/drivers/net/ethernet/intel/ice/ice_ptp.c
> +++ b/drivers/net/ethernet/intel/ice/ice_ptp.c
> @@ -2147,30 +2147,24 @@ int ice_ptp_set_ts_config(struct ice_pf *pf, struct ifreq *ifr)
> }
>
> /**
> - * ice_ptp_rx_hwtstamp - Check for an Rx timestamp
> - * @rx_ring: Ring to get the VSI info
> + * ice_ptp_get_rx_hwts - Get packet Rx timestamp
> * @rx_desc: Receive descriptor
> - * @skb: Particular skb to send timestamp with
> + * @cached_time: Cached PHC time
> *
> * The driver receives a notification in the receive descriptor with timestamp.
> - * The timestamp is in ns, so we must convert the result first.
> */
> -void
> -ice_ptp_rx_hwtstamp(struct ice_rx_ring *rx_ring,
> - union ice_32b_rx_flex_desc *rx_desc, struct sk_buff *skb)
> +u64 ice_ptp_get_rx_hwts(const union ice_32b_rx_flex_desc *rx_desc,
> + u64 cached_time)
> {
> - struct skb_shared_hwtstamps *hwtstamps;
> - u64 ts_ns, cached_time;
> u32 ts_high;
> + u64 ts_ns;
>
> if (!(rx_desc->wb.time_stamp_low & ICE_PTP_TS_VALID))
> - return;
> -
> - cached_time = READ_ONCE(rx_ring->cached_phctime);
> + return 0;
>
> /* Do not report a timestamp if we don't have a cached PHC time */
> if (!cached_time)
> - return;
> + return 0;
>
> /* Use ice_ptp_extend_32b_ts directly, using the ring-specific cached
> * PHC value, rather than accessing the PF. This also allows us to
> @@ -2181,9 +2175,7 @@ ice_ptp_rx_hwtstamp(struct ice_rx_ring *rx_ring,
> ts_high = le32_to_cpu(rx_desc->wb.flex_ts.ts_high);
> ts_ns = ice_ptp_extend_32b_ts(cached_time, ts_high);
>
> - hwtstamps = skb_hwtstamps(skb);
> - memset(hwtstamps, 0, sizeof(*hwtstamps));
> - hwtstamps->hwtstamp = ns_to_ktime(ts_ns);
> + return ts_ns;
> }
>
> /**
> diff --git a/drivers/net/ethernet/intel/ice/ice_ptp.h b/drivers/net/ethernet/intel/ice/ice_ptp.h
> index 995a57019ba7..523eefbfdf95 100644
> --- a/drivers/net/ethernet/intel/ice/ice_ptp.h
> +++ b/drivers/net/ethernet/intel/ice/ice_ptp.h
> @@ -268,9 +268,8 @@ void ice_ptp_extts_event(struct ice_pf *pf);
> s8 ice_ptp_request_ts(struct ice_ptp_tx *tx, struct sk_buff *skb);
> enum ice_tx_tstamp_work ice_ptp_process_ts(struct ice_pf *pf);
>
> -void
> -ice_ptp_rx_hwtstamp(struct ice_rx_ring *rx_ring,
> - union ice_32b_rx_flex_desc *rx_desc, struct sk_buff *skb);
> +u64 ice_ptp_get_rx_hwts(const union ice_32b_rx_flex_desc *rx_desc,
> + u64 cached_time);
> void ice_ptp_reset(struct ice_pf *pf);
> void ice_ptp_prepare_for_reset(struct ice_pf *pf);
> void ice_ptp_init(struct ice_pf *pf);
> @@ -304,9 +303,13 @@ static inline bool ice_ptp_process_ts(struct ice_pf *pf)
> {
> return true;
> }
> -static inline void
> -ice_ptp_rx_hwtstamp(struct ice_rx_ring *rx_ring,
> - union ice_32b_rx_flex_desc *rx_desc, struct sk_buff *skb) { }
> +
> +static inline u64
> +ice_ptp_get_rx_hwts(const union ice_32b_rx_flex_desc *rx_desc, u64 cached_time)
> +{
> + return 0;
> +}
> +
> static inline void ice_ptp_reset(struct ice_pf *pf) { }
> static inline void ice_ptp_prepare_for_reset(struct ice_pf *pf) { }
> static inline void ice_ptp_init(struct ice_pf *pf) { }
> diff --git a/drivers/net/ethernet/intel/ice/ice_txrx_lib.c b/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
> index 8f7f6d78f7bf..b2f241b73934 100644
> --- a/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
> +++ b/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
> @@ -185,6 +185,29 @@ ice_rx_csum(struct ice_rx_ring *ring, struct sk_buff *skb,
> ring->vsi->back->hw_csum_rx_error++;
> }
>
> +/**
> + * ice_ptp_rx_hwts_to_skb - Put RX timestamp into skb
> + * @rx_ring: Ring to get the VSI info
> + * @rx_desc: Receive descriptor
> + * @skb: Particular skb to send timestamp with
> + *
> + * The timestamp is in ns, so we must convert the result first.
> + */
> +static void
> +ice_ptp_rx_hwts_to_skb(struct ice_rx_ring *rx_ring,
> + const union ice_32b_rx_flex_desc *rx_desc,
> + struct sk_buff *skb)
> +{
> + u64 ts_ns, cached_time;
> +
> + cached_time = READ_ONCE(rx_ring->cached_phctime);

any reason for not reading cached_phctime within ice_ptp_get_rx_hwts?

> + ts_ns = ice_ptp_get_rx_hwts(rx_desc, cached_time);
> +
> + *skb_hwtstamps(skb) = (struct skb_shared_hwtstamps){
> + .hwtstamp = ns_to_ktime(ts_ns),
> + };
> +}
> +
> /**
> * ice_process_skb_fields - Populate skb header fields from Rx descriptor
> * @rx_ring: Rx descriptor ring packet is being transacted on
> @@ -209,7 +232,7 @@ ice_process_skb_fields(struct ice_rx_ring *rx_ring,
> ice_rx_csum(rx_ring, skb, rx_desc, ptype);
>
> if (rx_ring->ptp_rx)
> - ice_ptp_rx_hwtstamp(rx_ring, rx_desc, skb);
> + ice_ptp_rx_hwts_to_skb(rx_ring, rx_desc, skb);
> }
>
> /**
> --
> 2.41.0
>
>