[Devel] [PATCH hci-8.1 v2 3/6] drivers/md/push_backup: do not re-arm deadline timer in push_backup_write()

[Andrey Zhadchenko]

pb_timer_func() checks pb->deadline_jiffies every time it fires,
so we actually don't need to re-arm the timer after setting the
filed.

This is also the only place that arms the timer outside the window
push_backup_stop() waits for with synchronize_rcu(). Today it is
harmless because write and stop are serialized by pb->ctl_rwsem,
but it would re-arm the timer behind timer_delete_sync_try() once
the write path is reachable without the rwsem (next patches).

https://virtuozzo.atlassian.net/browse/VSTOR-152912
Signed-off-by: Andrey Zhadchenko <andrey.zhadchenko at virtuozzo.com>
---
v2: no changes

 drivers/md/dm-push-backup.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/drivers/md/dm-push-backup.c b/drivers/md/dm-push-backup.c
index 1ae4ccc208ffa..8ce84a1a696e5 100644
--- a/drivers/md/dm-push-backup.c
+++ b/drivers/md/dm-push-backup.c
@@ -467,8 +467,8 @@ static int push_backup_write(struct push_backup *pb,
 			     unsigned int clu, unsigned int nr)
 {
 	u64 i, key, nr_clus = pb->nr_clus;
-	bool finished, has_more = false;
 	LIST_HEAD(pbio_list);
+	bool finished;
 	struct pb_bio *pbio;
 
 	if (!pb)
@@ -519,8 +519,7 @@ static int push_backup_write(struct push_backup *pb,
 		}
 	}
 
-	has_more = (pb->nr_delayed != 0);
-	if (has_more)
+	if (pb->nr_delayed)
 		pb->deadline_jiffies = get_jiffies_64() + pb->timeout_in_jiffies;
 	else
 		pb->deadline_jiffies = S64_MAX;
@@ -529,11 +528,8 @@ static int push_backup_write(struct push_backup *pb,
 	if (finished)
 		wake_up_interruptible(&pb->waitq);
 
-	if (!list_empty(&pbio_list)) {
+	if (!list_empty(&pbio_list))
 		resubmit_pbios(pb, &pbio_list);
-		if (has_more)
-			mod_timer(&pb->deadline_timer, pb->timeout_in_jiffies + 1);
-	}
 
 	return 0;
 }
-- 
2.43.5