5.15-stable review patch. If anyone has any objections, please let me know.
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From: Christopher S M Hall christopher.s.hall@intel.com
[ Upstream commit cd7f7328d691937102732f39f97ead35b15bf803 ]
Move ktime_get_snapshot() into the loop. If a retry does occur, a more recent snapshot will result in a more accurate cross-timestamp.
Fixes: a90ec8483732 ("igc: Add support for PTP getcrosststamp()") Reviewed-by: Michal Swiatkowski michal.swiatkowski@linux.intel.com Tested-by: Mor Bar-Gabay morx.bar.gabay@intel.com Tested-by: Avigail Dahan avigailx.dahan@intel.com Signed-off-by: Christopher S M Hall christopher.s.hall@intel.com Reviewed-by: Corinna Vinschen vinschen@redhat.com Signed-off-by: Jacob Keller jacob.e.keller@intel.com Acked-by: Vinicius Costa Gomes vinicius.gomes@intel.com Signed-off-by: Tony Nguyen anthony.l.nguyen@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/intel/igc/igc_ptp.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/net/ethernet/intel/igc/igc_ptp.c b/drivers/net/ethernet/intel/igc/igc_ptp.c index d0363bd68e5ed..863669192301e 100644 --- a/drivers/net/ethernet/intel/igc/igc_ptp.c +++ b/drivers/net/ethernet/intel/igc/igc_ptp.c @@ -886,16 +886,16 @@ static int igc_phc_get_syncdevicetime(ktime_t *device, int err, count = 100; ktime_t t1, t2_curr;
- /* Get a snapshot of system clocks to use as historic value. */ - ktime_get_snapshot(&adapter->snapshot); - + /* Doing this in a loop because in the event of a + * badly timed (ha!) system clock adjustment, we may + * get PTM errors from the PCI root, but these errors + * are transitory. Repeating the process returns valid + * data eventually. + */ do { - /* Doing this in a loop because in the event of a - * badly timed (ha!) system clock adjustment, we may - * get PTM errors from the PCI root, but these errors - * are transitory. Repeating the process returns valid - * data eventually. - */ + /* Get a snapshot of system clocks to use as historic value. */ + ktime_get_snapshot(&adapter->snapshot); + igc_ptm_trigger(hw);
err = readx_poll_timeout(rd32, IGC_PTM_STAT, stat,