mlx5_en: use read sequence for gettimex64

jira LE-3615
Rebuild_History Non-Buildable kernel-5.14.0-570.28.1.el9_6
commit-author Vadim Fedorenko <[email protected]>
commit 0452a2d

The gettimex64() doesn't modify values in timecounter, that's why there
is no need to update sequence counter. Reduce the contention on sequence
lock for multi-thread PHC reading use-case.

	Signed-off-by: Vadim Fedorenko <[email protected]>
	Reviewed-by: Rahul Rameshbabu <[email protected]>
	Acked-by: Tariq Toukan <[email protected]>
Link: https://patch.msgid.link/[email protected]
	Signed-off-by: Jakub Kicinski <[email protected]>
(cherry picked from commit 0452a2d)
	Signed-off-by: Jonathan Maple <[email protected]>

Author: PlaidCat

drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c

@@ -402,9 +402,7 @@ static int mlx5_ptp_gettimex(struct ptp_clock_info *ptp, struct timespec64 *ts,
 			     struct ptp_system_timestamp *sts)
 {
 	struct mlx5_clock *clock = container_of(ptp, struct mlx5_clock, ptp_info);
-	struct mlx5_timer *timer = &clock->timer;
 	struct mlx5_core_dev *mdev;
-	unsigned long flags;
 	u64 cycles, ns;
 
 	mdev = container_of(clock, struct mlx5_core_dev, clock);
@@ -413,10 +411,8 @@ static int mlx5_ptp_gettimex(struct ptp_clock_info *ptp, struct timespec64 *ts,
 		goto out;
 	}
 
-	write_seqlock_irqsave(&clock->lock, flags);
 	cycles = mlx5_read_time(mdev, sts, false);
-	ns = timecounter_cyc2time(&timer->tc, cycles);
-	write_sequnlock_irqrestore(&clock->lock, flags);
+	ns = mlx5_timecounter_cyc2time(clock, cycles);
 	*ts = ns_to_timespec64(ns);
 out:
 	return 0;