This is a note to let you know that I've just added the patch titled dm mpath: only use ktime_get_ns() in historical selector to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: dm-mpath-only-use-ktime_get_ns-in-historical-selecto.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 0da48a9237a6094af4f97e44a3567d1f97437196 Author: Khazhismel Kumykov <khazhy@xxxxxxxxxx> Date: Mon Apr 11 15:03:35 2022 -0700 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@xxxxxxxxxx> Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/md/dm-historical-service-time.c b/drivers/md/dm-historical-service-time.c index 186f91e2752c..06fe43c13ba3 100644 --- a/drivers/md/dm-historical-service-time.c +++ b/drivers/md/dm-historical-service-time.c @@ -429,7 +429,7 @@ 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; @@ -470,7 +470,7 @@ 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 @@ -479,11 +479,11 @@ 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,