Commit ce40426f authored by Khazhismel Kumykov's avatar Khazhismel Kumykov Committed by Mike Snitzer
Browse files

dm mpath: only use ktime_get_ns() in historical selector 



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: 2613eab1 ("dm mpath: add Historical Service Time Path Selector")
Signed-off-by: default avatarKhazhismel Kumykov <khazhy@google.com>
Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
parent 08c1af8f

drivers/md/dm-ps-historical-service-time.c

+5 −6
Original line number Diff line number Diff line
@@ -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,