[Devel] [PATCH hci-8.1 v3 3/6] drivers/md/push_backup: do not re-arm deadline timer in push_backup_write()

[Alexander Ivanov]

On 11/3/26 07:17, Andrey Zhadchenko wrote:
> 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.
filed - > field?
>
> 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
> v3: 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;
>   }