[net-next,v2,0/3] ice: lighter locking for PTP time reading

Message

Michal Schmidt March 6, 2024, 4:29 p.m. UTC

This series removes the use of the heavy-weight PTP hardware semaphore
in the gettimex64 path. Instead, serialization of access to the time
register is done using a host-side spinlock. The timer hardware is
shared between PFs on the PCI adapter, so the spinlock must be shared
between ice_pf instances too.

Replacing the PTP hardware semaphore entirely with a mutex is also
possible and you can see it done in my git branch[1], but I am not
posting those patches yet to keep the scope of this series limited.

[1] https://gitlab.com/mschmidt2/linux/-/commits/ice-ptp-host-side-lock-8

v2:
 - Patch 1: Rely on xarray's own lock. (Suggested by Jiri Pirko)
 - Patch 2: Do not use *_irqsave with ptp_gltsyn_time_lock, as it's used
   only in process contexts.

Michal Schmidt (3):
  ice: add ice_adapter for shared data across PFs on the same NIC
  ice: avoid the PTP hardware semaphore in gettimex64 path
  ice: fold ice_ptp_read_time into ice_ptp_gettimex64

 drivers/net/ethernet/intel/ice/Makefile      |  3 +-
 drivers/net/ethernet/intel/ice/ice.h         |  2 +
 drivers/net/ethernet/intel/ice/ice_adapter.c | 87 ++++++++++++++++++++
 drivers/net/ethernet/intel/ice/ice_adapter.h | 28 +++++++
 drivers/net/ethernet/intel/ice/ice_main.c    |  8 ++
 drivers/net/ethernet/intel/ice/ice_ptp.c     | 33 +-------
 drivers/net/ethernet/intel/ice/ice_ptp_hw.c  |  3 +
 7 files changed, 134 insertions(+), 30 deletions(-)
 create mode 100644 drivers/net/ethernet/intel/ice/ice_adapter.c
 create mode 100644 drivers/net/ethernet/intel/ice/ice_adapter.h