dm mpath: only use ktime_get_ns() in historical selector

[ Upstream commit ce40426fdc3c92acdba6b5ca74bc7277ffaa6a3d ]

Mixing sched_clock() and ktime_get_ns() usage will give bad results.

Switch hst_select_path() from using sched_clock() to ktime_get_ns().
Also rename path_service_time()'s 'sched_now' variable to 'now'.

Fixes: 2613eab11996 ("dm mpath: add Historical Service Time Path Selector")
Signed-off-by: Khazhismel Kumykov <khazhy@google.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/md/dm-ps-historical-service-time.c b/drivers/md/dm-ps-historical-service-time.c
index 1856a1b..82f2a06 100644 (file)
--- a/drivers/md/dm-ps-historical-service-time.c
+++ b/drivers/md/dm-ps-historical-service-time.c
@@ -432,7 +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;
 
@@ -473,7 +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
@@ -482,11 +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,