On 01/27/2018 06:23 AM, Coly Li wrote: > dc->writeback_rate_update_seconds can be set via sysfs and its value can > be set to [1, ULONG_MAX]. It does not make sense to set such a large > value, 60 seconds is long enough value considering the default 5 seconds > works well for long time. > > Because dc->writeback_rate_update is a special delayed work, it re-arms > itself inside the delayed work routine update_writeback_rate(). When > stopping it by cancel_delayed_work_sync(), there should be a timeout to > wait and make sure the re-armed delayed work is stopped too. A small max > value of dc->writeback_rate_update_seconds is also helpful to decide a > reasonable small timeout. > > This patch limits sysfs interface to set dc->writeback_rate_update_seconds > in range of [1, 60] seconds, and replaces the hand-coded number by macros. > > Signed-off-by: Coly Li <[email protected]> > Reviewed-by: Hannes Reinecke <[email protected]>
[snip] > --- > drivers/md/bcache/sysfs.c | 3 +++ > drivers/md/bcache/writeback.c | 2 +- > drivers/md/bcache/writeback.h | 3 +++ > 3 files changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c > index b4184092c727..a74a752c9e0f 100644 > --- a/drivers/md/bcache/sysfs.c > +++ b/drivers/md/bcache/sysfs.c > @@ -215,6 +215,9 @@ STORE(__cached_dev) > sysfs_strtoul_clamp(writeback_rate, > dc->writeback_rate.rate, 1, INT_MAX); > > + sysfs_strtoul_clamp(writeback_rate_update_seconds, > + dc->writeback_rate_update_seconds, > + 1, WRITEBACK_RATE_UPDATE_SECS_MAX); > d_strtoul_nonzero(writeback_rate_update_seconds); Doesn't the above line need to be removed for this to work? Mike
