1 /*
2  * Copyright (C) 2017 Red Hat. All rights reserved.
3  *
4  * This file is released under the GPL.
5  */
6 
7 #ifndef DM_CACHE_BACKGROUND_WORK_H
8 #define DM_CACHE_BACKGROUND_WORK_H
9 
10 #include <linux/vmalloc.h>
11 #include "dm-cache-policy.h"
12 
13 /*----------------------------------------------------------------*/
14 
15 struct background_work;
16 struct background_tracker;
17 
18 /*
19  * FIXME: discuss lack of locking in all methods.
20  */
21 struct background_tracker *btracker_create(unsigned max_work);
22 void btracker_destroy(struct background_tracker *b);
23 
24 unsigned btracker_nr_writebacks_queued(struct background_tracker *b);
25 unsigned btracker_nr_demotions_queued(struct background_tracker *b);
26 
27 /*
28  * returns -EINVAL iff the work is already queued.  -ENOMEM if the work
29  * couldn't be queued for another reason.
30  */
31 int btracker_queue(struct background_tracker *b,
32 		   struct policy_work *work,
33 		   struct policy_work **pwork);
34 
35 /*
36  * Returns -ENODATA if there's no work.
37  */
38 int btracker_issue(struct background_tracker *b, struct policy_work **work);
39 void btracker_complete(struct background_tracker *b,
40 		       struct policy_work *op);
41 bool btracker_promotion_already_present(struct background_tracker *b,
42 					dm_oblock_t oblock);
43 
44 /*----------------------------------------------------------------*/
45 
46 #endif
47