Khazhismel Kumykov <kha...@google.com> writes:

> mixing sched_clock() and ktime_get_ns() will give bad results, don't do
> it
>
> Fixes: 2613eab11996 ("dm mpath: add Historical Service Time Path Selector")
> Signed-off-by: Khazhismel Kumykov <kha...@google.com>

Looks good.

Reviewed-by: Gabriel Krisman Bertazi <kris...@collabora.com>


> ---
>  drivers/md/dm-ps-historical-service-time.c | 11 +++++------
>  1 file changed, 5 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/md/dm-ps-historical-service-time.c 
> b/drivers/md/dm-ps-historical-service-time.c
> index 875bca30a0dd..82f2a06153dc 100644
> --- a/drivers/md/dm-ps-historical-service-time.c
> +++ b/drivers/md/dm-ps-historical-service-time.c
> @@ -27,7 +27,6 @@
>  #include <linux/blkdev.h>
>  #include <linux/slab.h>
>  #include <linux/module.h>
> -#include <linux/sched/clock.h>
>  
>  
>  #define DM_MSG_PREFIX        "multipath historical-service-time"
> @@ -433,7 +432,7 @@ static struct dm_path *hst_select_path(struct 
> path_selector *ps,
>  {
>       struct selector *s = ps->context;
>       struct path_info *pi = NULL, *best = NULL;
> -     u64 time_now = sched_clock();
> +     u64 time_now = ktime_get_ns();
>       struct dm_path *ret = NULL;
>       unsigned long flags;
>  
> @@ -474,7 +473,7 @@ static int hst_start_io(struct path_selector *ps, struct 
> dm_path *path,
>  
>  static u64 path_service_time(struct path_info *pi, u64 start_time)
>  {
> -     u64 sched_now = ktime_get_ns();
> +     u64 now = ktime_get_ns();
>  
>       /* if a previous disk request has finished after this IO was
>        * sent to the hardware, pretend the submission happened
> @@ -483,11 +482,11 @@ static u64 path_service_time(struct path_info *pi, u64 
> start_time)
>       if (time_after64(pi->last_finish, start_time))
>               start_time = pi->last_finish;
>  
> -     pi->last_finish = sched_now;
> -     if (time_before64(sched_now, start_time))
> +     pi->last_finish = now;
> +     if (time_before64(now, start_time))
>               return 0;
>  
> -     return sched_now - start_time;
> +     return now - start_time;
>  }
>  
>  static int hst_end_io(struct path_selector *ps, struct dm_path *path,

-- 
Gabriel Krisman Bertazi

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