1#ifndef IOU_REQ_REF_H
2#define IOU_REQ_REF_H
3
4#include <linux/atomic.h>
5#include <linux/io_uring_types.h>
6
7/*
8 * Shamelessly stolen from the mm implementation of page reference checking,
9 * see commit f958d7b528b1 for details.
10 */
11#define req_ref_zero_or_close_to_overflow(req) \
12 ((unsigned int) atomic_read(&(req->refs)) + 127u <= 127u)
13
14static inline bool req_ref_inc_not_zero(struct io_kiocb *req)
15{
16 WARN_ON_ONCE(!(req->flags & REQ_F_REFCOUNT));
17 return atomic_inc_not_zero(v: &req->refs);
18}
19
20static inline bool req_ref_put_and_test_atomic(struct io_kiocb *req)
21{
22 WARN_ON_ONCE(!(data_race(req->flags) & REQ_F_REFCOUNT));
23 WARN_ON_ONCE(req_ref_zero_or_close_to_overflow(req));
24 return atomic_dec_and_test(v: &req->refs);
25}
26
27static inline bool req_ref_put_and_test(struct io_kiocb *req)
28{
29 if (likely(!(req->flags & REQ_F_REFCOUNT)))
30 return true;
31
32 WARN_ON_ONCE(req_ref_zero_or_close_to_overflow(req));
33 return atomic_dec_and_test(v: &req->refs);
34}
35
36static inline void req_ref_get(struct io_kiocb *req)
37{
38 WARN_ON_ONCE(!(req->flags & REQ_F_REFCOUNT));
39 WARN_ON_ONCE(req_ref_zero_or_close_to_overflow(req));
40 atomic_inc(v: &req->refs);
41}
42
43static inline void req_ref_put(struct io_kiocb *req)
44{
45 WARN_ON_ONCE(!(req->flags & REQ_F_REFCOUNT));
46 WARN_ON_ONCE(req_ref_zero_or_close_to_overflow(req));
47 atomic_dec(v: &req->refs);
48}
49
50static inline void __io_req_set_refcount(struct io_kiocb *req, int nr)
51{
52 if (!(req->flags & REQ_F_REFCOUNT)) {
53 req->flags |= REQ_F_REFCOUNT;
54 atomic_set(v: &req->refs, i: nr);
55 }
56}
57
58static inline void io_req_set_refcount(struct io_kiocb *req)
59{
60 __io_req_set_refcount(req, nr: 1);
61}
62#endif
63