md: minor cleanup in safe_delay_store.

There isn't really much room for races with ->safemode_delay.
But as I am trying to clean up any racy code and will soon
be removing reconfig_mutex protection from most _store()
functions:
 - only set mddev->safemode_delay once, to ensure no code
   can see an intermediate value
 - use safemode_timer to call md_safemode_timeout() rather than
   calling it directly, to ensure it never races with itself.

Signed-off-by: NeilBrown <neilb@suse.de>

1 files changed, 7 insertions, 5 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 5a949166dac0..0f9bc9a02a1b 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -3242,11 +3242,13 @@ safe_delay_store(struct mddev *mddev, const char *cbuf, size_t len)
                 mddev->safemode_delay = 0;
         else {
                 unsigned long old_delay = mddev->safemode_delay;
-                mddev->safemode_delay = (msec*HZ)/1000;
-                if (mddev->safemode_delay == 0)
-                        mddev->safemode_delay = 1;
-                if (mddev->safemode_delay < old_delay || old_delay == 0)
-                        md_safemode_timeout((unsigned long)mddev);
+                unsigned long new_delay = (msec*HZ)/1000;
+
+                if (new_delay == 0)
+                        new_delay = 1;
+                mddev->safemode_delay = new_delay;
+                if (new_delay < old_delay || old_delay == 0)
+                        mod_timer(&mddev->safemode_timer, jiffies+1);
         }
         return len;
 }