SLOW_WORK: Add delayed_slow_work support

This adds support for starting slow work with a delay, similar
to the functionality we have for workqueues.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/include/linux/slow-work.h b/include/linux/slow-work.h
index eef20182d5b4..b245b9a9cc0b 100644
--- a/include/linux/slow-work.h
+++ b/include/linux/slow-work.h
@@ -17,6 +17,7 @@
 #ifdef CONFIG_SLOW_WORK
 
 #include <linux/sysctl.h>
+#include <linux/timer.h>
 
 struct slow_work;
 
@@ -52,10 +53,16 @@ struct slow_work {
 #define SLOW_WORK_ENQ_DEFERRED  2       /* item enqueue deferred */
 #define SLOW_WORK_VERY_SLOW     3       /* item is very slow */
 #define SLOW_WORK_CANCELLING    4       /* item is being cancelled, don't enqueue */
+#define SLOW_WORK_DELAYED       5       /* item is struct delayed_slow_work with active timer */
         const struct slow_work_ops *ops; /* operations table for this item */
         struct list_head        link;   /* link in queue */
 };
 
+struct delayed_slow_work {
+        struct slow_work        work;
+        struct timer_list       timer;
+};
+
 /**
  * slow_work_init - Initialise a slow work item
  * @work: The work item to initialise
@@ -72,6 +79,20 @@ static inline void slow_work_init(struct slow_work *work,
 }
 
 /**
+ * slow_work_init - Initialise a delayed slow work item
+ * @work: The work item to initialise
+ * @ops: The operations to use to handle the slow work item
+ *
+ * Initialise a delayed slow work item.
+ */
+static inline void delayed_slow_work_init(struct delayed_slow_work *dwork,
+                                          const struct slow_work_ops *ops)
+{
+        init_timer(&dwork->timer);
+        slow_work_init(&dwork->work, ops);
+}
+
+/**
  * vslow_work_init - Initialise a very slow work item
  * @work: The work item to initialise
  * @ops: The operations to use to handle the slow work item
@@ -93,6 +114,14 @@ extern void slow_work_cancel(struct slow_work *work);
 extern int slow_work_register_user(struct module *owner);
 extern void slow_work_unregister_user(struct module *owner);
 
+extern int delayed_slow_work_enqueue(struct delayed_slow_work *dwork,
+                                     unsigned long delay);
+
+static inline void delayed_slow_work_cancel(struct delayed_slow_work *dwork)
+{
+        slow_work_cancel(&dwork->work);
+}
+
 #ifdef CONFIG_SYSCTL
 extern ctl_table slow_work_sysctls[];
 #endif