md: delay notification of 'active_idle' to the recovery thread

sysfs_notify might sleep, so do not call it from md_safemode_timeout.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/md/md.c

@@ -3483,7 +3483,7 @@ static void md_safemode_timeout(unsigned long data)
 	if (!atomic_read(&mddev->writes_pending)) {
 		mddev->safemode = 1;
 		if (mddev->external)
-			sysfs_notify(&mddev->kobj, NULL, "array_state");
+			set_bit(MD_NOTIFY_ARRAY_STATE, &mddev->flags);
 	}
 	md_wakeup_thread(mddev->thread);
 }
@@ -6051,6 +6051,9 @@ void md_check_recovery(mddev_t *mddev)
 	if (mddev->bitmap)
 		bitmap_daemon_work(mddev->bitmap);
 
+	if (test_and_clear_bit(MD_NOTIFY_ARRAY_STATE, &mddev->flags))
+		sysfs_notify(&mddev->kobj, NULL, "array_state");
+
 	if (mddev->ro)
 		return;
 

include/linux/raid/md_k.h

@@ -128,6 +128,7 @@ struct mddev_s
 #define MD_CHANGE_DEVS	0	/* Some device status has changed */
 #define MD_CHANGE_CLEAN 1	/* transition to or from 'clean' */
 #define MD_CHANGE_PENDING 2	/* superblock update in progress */
+#define MD_NOTIFY_ARRAY_STATE 3	/* atomic context wants to notify userspace */
 
 	int				ro;