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1/* SPDX-License-Identifier: GPL-2.0+ */
2/*
3 * RCU segmented callback lists, internal-to-rcu header file
4 *
5 * Copyright IBM Corporation, 2017
6 *
7 * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
8 */
9
10#include <linux/rcu_segcblist.h>
11
12/* Return number of callbacks in the specified callback list. */
13static inline long rcu_cblist_n_cbs(struct rcu_cblist *rclp)
14{
15 return READ_ONCE(rclp->len);
16}
17
18/*
19 * Account for the fact that a previously dequeued callback turned out
20 * to be marked as lazy.
21 */
22static inline void rcu_cblist_dequeued_lazy(struct rcu_cblist *rclp)
23{
24 rclp->len_lazy--;
25}
26
27void rcu_cblist_init(struct rcu_cblist *rclp);
28void rcu_cblist_enqueue(struct rcu_cblist *rclp, struct rcu_head *rhp);
29void rcu_cblist_flush_enqueue(struct rcu_cblist *drclp,
30 struct rcu_cblist *srclp,
31 struct rcu_head *rhp);
32struct rcu_head *rcu_cblist_dequeue(struct rcu_cblist *rclp);
33
34/*
35 * Is the specified rcu_segcblist structure empty?
36 *
37 * But careful! The fact that the ->head field is NULL does not
38 * necessarily imply that there are no callbacks associated with
39 * this structure. When callbacks are being invoked, they are
40 * removed as a group. If callback invocation must be preempted,
41 * the remaining callbacks will be added back to the list. Either
42 * way, the counts are updated later.
43 *
44 * So it is often the case that rcu_segcblist_n_cbs() should be used
45 * instead.
46 */
47static inline bool rcu_segcblist_empty(struct rcu_segcblist *rsclp)
48{
49 return !READ_ONCE(rsclp->head);
50}
51
52/* Return number of callbacks in segmented callback list. */
53static inline long rcu_segcblist_n_cbs(struct rcu_segcblist *rsclp)
54{
55#ifdef CONFIG_RCU_NOCB_CPU
56 return atomic_long_read(&rsclp->len);
57#else
58 return READ_ONCE(rsclp->len);
59#endif
60}
61
62/* Return number of lazy callbacks in segmented callback list. */
63static inline long rcu_segcblist_n_lazy_cbs(struct rcu_segcblist *rsclp)
64{
65 return rsclp->len_lazy;
66}
67
68/* Return number of lazy callbacks in segmented callback list. */
69static inline long rcu_segcblist_n_nonlazy_cbs(struct rcu_segcblist *rsclp)
70{
71 return rcu_segcblist_n_cbs(rsclp) - rsclp->len_lazy;
72}
73
74/*
75 * Is the specified rcu_segcblist enabled, for example, not corresponding
76 * to an offline CPU?
77 */
78static inline bool rcu_segcblist_is_enabled(struct rcu_segcblist *rsclp)
79{
80 return rsclp->enabled;
81}
82
83/* Is the specified rcu_segcblist offloaded? */
84static inline bool rcu_segcblist_is_offloaded(struct rcu_segcblist *rsclp)
85{
86 return rsclp->offloaded;
87}
88
89/*
90 * Are all segments following the specified segment of the specified
91 * rcu_segcblist structure empty of callbacks? (The specified
92 * segment might well contain callbacks.)
93 */
94static inline bool rcu_segcblist_restempty(struct rcu_segcblist *rsclp, int seg)
95{
96 return !READ_ONCE(*READ_ONCE(rsclp->tails[seg]));
97}
98
99void rcu_segcblist_inc_len(struct rcu_segcblist *rsclp);
100void rcu_segcblist_init(struct rcu_segcblist *rsclp);
101void rcu_segcblist_disable(struct rcu_segcblist *rsclp);
102void rcu_segcblist_offload(struct rcu_segcblist *rsclp);
103bool rcu_segcblist_ready_cbs(struct rcu_segcblist *rsclp);
104bool rcu_segcblist_pend_cbs(struct rcu_segcblist *rsclp);
105struct rcu_head *rcu_segcblist_first_cb(struct rcu_segcblist *rsclp);
106struct rcu_head *rcu_segcblist_first_pend_cb(struct rcu_segcblist *rsclp);
107bool rcu_segcblist_nextgp(struct rcu_segcblist *rsclp, unsigned long *lp);
108void rcu_segcblist_enqueue(struct rcu_segcblist *rsclp,
109 struct rcu_head *rhp, bool lazy);
110bool rcu_segcblist_entrain(struct rcu_segcblist *rsclp,
111 struct rcu_head *rhp, bool lazy);
112void rcu_segcblist_extract_count(struct rcu_segcblist *rsclp,
113 struct rcu_cblist *rclp);
114void rcu_segcblist_extract_done_cbs(struct rcu_segcblist *rsclp,
115 struct rcu_cblist *rclp);
116void rcu_segcblist_extract_pend_cbs(struct rcu_segcblist *rsclp,
117 struct rcu_cblist *rclp);
118void rcu_segcblist_insert_count(struct rcu_segcblist *rsclp,
119 struct rcu_cblist *rclp);
120void rcu_segcblist_insert_done_cbs(struct rcu_segcblist *rsclp,
121 struct rcu_cblist *rclp);
122void rcu_segcblist_insert_pend_cbs(struct rcu_segcblist *rsclp,
123 struct rcu_cblist *rclp);
124void rcu_segcblist_advance(struct rcu_segcblist *rsclp, unsigned long seq);
125bool rcu_segcblist_accelerate(struct rcu_segcblist *rsclp, unsigned long seq);
126void rcu_segcblist_merge(struct rcu_segcblist *dst_rsclp,
127 struct rcu_segcblist *src_rsclp);
1/* SPDX-License-Identifier: GPL-2.0+ */
2/*
3 * RCU segmented callback lists, internal-to-rcu header file
4 *
5 * Copyright IBM Corporation, 2017
6 *
7 * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
8 */
9
10#include <linux/rcu_segcblist.h>
11
12/* Return number of callbacks in the specified callback list. */
13static inline long rcu_cblist_n_cbs(struct rcu_cblist *rclp)
14{
15 return READ_ONCE(rclp->len);
16}
17
18/* Return number of callbacks in segmented callback list by summing seglen. */
19long rcu_segcblist_n_segment_cbs(struct rcu_segcblist *rsclp);
20
21void rcu_cblist_init(struct rcu_cblist *rclp);
22void rcu_cblist_enqueue(struct rcu_cblist *rclp, struct rcu_head *rhp);
23void rcu_cblist_flush_enqueue(struct rcu_cblist *drclp,
24 struct rcu_cblist *srclp,
25 struct rcu_head *rhp);
26struct rcu_head *rcu_cblist_dequeue(struct rcu_cblist *rclp);
27
28/*
29 * Is the specified rcu_segcblist structure empty?
30 *
31 * But careful! The fact that the ->head field is NULL does not
32 * necessarily imply that there are no callbacks associated with
33 * this structure. When callbacks are being invoked, they are
34 * removed as a group. If callback invocation must be preempted,
35 * the remaining callbacks will be added back to the list. Either
36 * way, the counts are updated later.
37 *
38 * So it is often the case that rcu_segcblist_n_cbs() should be used
39 * instead.
40 */
41static inline bool rcu_segcblist_empty(struct rcu_segcblist *rsclp)
42{
43 return !READ_ONCE(rsclp->head);
44}
45
46/* Return number of callbacks in segmented callback list. */
47static inline long rcu_segcblist_n_cbs(struct rcu_segcblist *rsclp)
48{
49#ifdef CONFIG_RCU_NOCB_CPU
50 return atomic_long_read(&rsclp->len);
51#else
52 return READ_ONCE(rsclp->len);
53#endif
54}
55
56static inline void rcu_segcblist_set_flags(struct rcu_segcblist *rsclp,
57 int flags)
58{
59 WRITE_ONCE(rsclp->flags, rsclp->flags | flags);
60}
61
62static inline void rcu_segcblist_clear_flags(struct rcu_segcblist *rsclp,
63 int flags)
64{
65 WRITE_ONCE(rsclp->flags, rsclp->flags & ~flags);
66}
67
68static inline bool rcu_segcblist_test_flags(struct rcu_segcblist *rsclp,
69 int flags)
70{
71 return READ_ONCE(rsclp->flags) & flags;
72}
73
74/*
75 * Is the specified rcu_segcblist enabled, for example, not corresponding
76 * to an offline CPU?
77 */
78static inline bool rcu_segcblist_is_enabled(struct rcu_segcblist *rsclp)
79{
80 return rcu_segcblist_test_flags(rsclp, SEGCBLIST_ENABLED);
81}
82
83/*
84 * Is the specified rcu_segcblist NOCB offloaded (or in the middle of the
85 * [de]offloading process)?
86 */
87static inline bool rcu_segcblist_is_offloaded(struct rcu_segcblist *rsclp)
88{
89 if (IS_ENABLED(CONFIG_RCU_NOCB_CPU) &&
90 rcu_segcblist_test_flags(rsclp, SEGCBLIST_LOCKING))
91 return true;
92
93 return false;
94}
95
96static inline bool rcu_segcblist_completely_offloaded(struct rcu_segcblist *rsclp)
97{
98 if (IS_ENABLED(CONFIG_RCU_NOCB_CPU) &&
99 !rcu_segcblist_test_flags(rsclp, SEGCBLIST_RCU_CORE))
100 return true;
101
102 return false;
103}
104
105/*
106 * Are all segments following the specified segment of the specified
107 * rcu_segcblist structure empty of callbacks? (The specified
108 * segment might well contain callbacks.)
109 */
110static inline bool rcu_segcblist_restempty(struct rcu_segcblist *rsclp, int seg)
111{
112 return !READ_ONCE(*READ_ONCE(rsclp->tails[seg]));
113}
114
115/*
116 * Is the specified segment of the specified rcu_segcblist structure
117 * empty of callbacks?
118 */
119static inline bool rcu_segcblist_segempty(struct rcu_segcblist *rsclp, int seg)
120{
121 if (seg == RCU_DONE_TAIL)
122 return &rsclp->head == rsclp->tails[RCU_DONE_TAIL];
123 return rsclp->tails[seg - 1] == rsclp->tails[seg];
124}
125
126void rcu_segcblist_inc_len(struct rcu_segcblist *rsclp);
127void rcu_segcblist_add_len(struct rcu_segcblist *rsclp, long v);
128void rcu_segcblist_init(struct rcu_segcblist *rsclp);
129void rcu_segcblist_disable(struct rcu_segcblist *rsclp);
130void rcu_segcblist_offload(struct rcu_segcblist *rsclp, bool offload);
131bool rcu_segcblist_ready_cbs(struct rcu_segcblist *rsclp);
132bool rcu_segcblist_pend_cbs(struct rcu_segcblist *rsclp);
133struct rcu_head *rcu_segcblist_first_cb(struct rcu_segcblist *rsclp);
134struct rcu_head *rcu_segcblist_first_pend_cb(struct rcu_segcblist *rsclp);
135bool rcu_segcblist_nextgp(struct rcu_segcblist *rsclp, unsigned long *lp);
136void rcu_segcblist_enqueue(struct rcu_segcblist *rsclp,
137 struct rcu_head *rhp);
138bool rcu_segcblist_entrain(struct rcu_segcblist *rsclp,
139 struct rcu_head *rhp);
140void rcu_segcblist_extract_done_cbs(struct rcu_segcblist *rsclp,
141 struct rcu_cblist *rclp);
142void rcu_segcblist_extract_pend_cbs(struct rcu_segcblist *rsclp,
143 struct rcu_cblist *rclp);
144void rcu_segcblist_insert_count(struct rcu_segcblist *rsclp,
145 struct rcu_cblist *rclp);
146void rcu_segcblist_insert_done_cbs(struct rcu_segcblist *rsclp,
147 struct rcu_cblist *rclp);
148void rcu_segcblist_insert_pend_cbs(struct rcu_segcblist *rsclp,
149 struct rcu_cblist *rclp);
150void rcu_segcblist_advance(struct rcu_segcblist *rsclp, unsigned long seq);
151bool rcu_segcblist_accelerate(struct rcu_segcblist *rsclp, unsigned long seq);
152void rcu_segcblist_merge(struct rcu_segcblist *dst_rsclp,
153 struct rcu_segcblist *src_rsclp);