[Intel-wired-lan] [PATCH iwl-net 1/3] ice: remove ptp_tx ring parameter flag

[Pucha, HimasekharX Reddy]

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces at osuosl.org> On Behalf Of Jacob Keller
> Sent: Saturday, November 4, 2023 5:17 AM
> To: Nguyen, Anthony L <anthony.l.nguyen at intel.com>
> Cc: Keller, Jacob E <jacob.e.keller at intel.com>; netdev at vger.kernel.org; Intel Wired LAN <intel-wired-lan at lists.osuosl.org>; Brandeburg, Jesse <jesse.brandeburg at intel.com>
> Subject: [Intel-wired-lan] [PATCH iwl-net 1/3] ice: remove ptp_tx ring parameter flag
>
> Before performing a Tx timestamp in ice_stamp(), the driver checks a ptp_tx
> ring variable to see if timestamping is enabled on that ring. This value is
> set for all rings whenever userspace configures Tx timestamping.
>
> Ostensibly this was done to avoid wasting cycles checking other fields when
> timestamping has not been enabled. However, for Tx timestamps we already
> get an individual per-SKB flag indicating whether userspace wants to
> request a timestamp on that packet. We do not gain much by also having
> a separate flag to check for whether timestamping was enabled.
>
> In fact, the driver currently fails to restore the field after a PF reset.
> Because of this, if a PF reset occurs, timestamps will be disabled.
>
> Since this flag doesn't add value in the hotpath, remove it and always
> provide a timestamp if the SKB flag has been set.
>
> A following change will fix the reset path to properly restore user
> timestamping configuration completely.
>
> This went unnoticed for some time because one of the most common
> applications using Tx timestamps, ptp4l, will reconfigure the socket as
> part of its fault recovery logic.
>
> Fixes: ea9b847cda64 ("ice: enable transmit timestamps for E810 devices")
> Signed-off-by: Jacob Keller <jacob.e.keller at intel.com>
> Reviewed-by: Jesse Brandeburg <jesse.brandeburg at intel.com>
> ---
>  drivers/net/ethernet/intel/ice/ice_ptp.c  | 14 --------------
>  drivers/net/ethernet/intel/ice/ice_txrx.c |  3 ---
>  drivers/net/ethernet/intel/ice/ice_txrx.h |  1 -
>  3 files changed, 18 deletions(-)
>

Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha at intel.com> (A Contingent worker at Intel)