Subject: [PATCH 11/53] net: macb: Fix ptp time adjustment for large negative delta

From: Harini Katakam <[email-masked]>
Date: Wed, 20 Jun 2018 17:04:20 +0530

[ Upstream commit 64d7839af8c8f67daaf9bf387135052c55d85f90 ]

When delta passed to gem_ptp_adjtime is negative, the sign is
maintained in the ns_to_timespec64 conversion. Hence timespec_add
should be used directly. timespec_sub will just subtract the negative
value thus increasing the time difference.

Signed-off-by: Harini Katakam <[email-masked]>
Acked-by: Nicolas Ferre <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 drivers/net/ethernet/cadence/macb_ptp.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb_ptp.c b/drivers/net/ethernet/cadence/macb_ptp.c
index 2220c771092b..678835136bf8 100644
--- a/drivers/net/ethernet/cadence/macb_ptp.c
+++ b/drivers/net/ethernet/cadence/macb_ptp.c
@@ -170,10 +170,7 @@ static int gem_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
 
 	if (delta > TSU_NSEC_MAX_VAL) {
 		gem_tsu_get_time(&bp->ptp_clock_info, &now);
-		if (sign)
-			now = timespec64_sub(now, then);
-		else
-			now = timespec64_add(now, then);
+		now = timespec64_add(now, then);
 
 		gem_tsu_set_time(&bp->ptp_clock_info,
 				 (const struct timespec64 *)&now);
-- 
2.17.1