2018-06-20 11:35:59

by Harini Katakam

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

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 protected]>
---
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 2220c77..6788351 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);
--
2.7.4

2018-06-20 14:06:16

by Nicolas Ferre

Subject: Re: [PATCH] net: macb: Fix ptp time adjustment for large negative delta

On 20/06/2018 at 13:34, Harini Katakam wrote:
> 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 protected]>

Makes sense:
Acked-by: Nicolas Ferre <[email protected]>

> ---
> 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 2220c77..6788351 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);
>


--
Nicolas Ferre

2018-06-21 06:02:41

by David Miller

Subject: Re: [PATCH] net: macb: Fix ptp time adjustment for large negative delta

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

> 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 protected]>

Applied and queued up for -stable.