From 7a5e3ecbe5b7b58e9a78a3738b28244982822e1c Mon Sep 17 00:00:00 2001 From: Coly Li Date: Wed, 7 Feb 2018 11:41:44 -0800 Subject: bcache: set writeback_rate_update_seconds in range [1, 60] seconds 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. Changelog: v2: fix a rebase typo in v4, which is pointed out by Michael Lyle. v1: initial version. Signed-off-by: Coly Li Reviewed-by: Hannes Reinecke Reviewed-by: Michael Lyle Signed-off-by: Jens Axboe --- drivers/md/bcache/sysfs.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'drivers/md/bcache/sysfs.c') diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c index c524305cc9a7..4a6a697e1680 100644 --- a/drivers/md/bcache/sysfs.c +++ b/drivers/md/bcache/sysfs.c @@ -218,7 +218,9 @@ STORE(__cached_dev) sysfs_strtoul_clamp(writeback_rate, dc->writeback_rate.rate, 1, INT_MAX); - d_strtoul_nonzero(writeback_rate_update_seconds); + sysfs_strtoul_clamp(writeback_rate_update_seconds, + dc->writeback_rate_update_seconds, + 1, WRITEBACK_RATE_UPDATE_SECS_MAX); d_strtoul(writeback_rate_i_term_inverse); d_strtoul_nonzero(writeback_rate_p_term_inverse); -- cgit v1.2.3