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8c366db0 | 1 | /* SPDX-License-Identifier: GPL-2.0+ */ |
d8be8173 PM |
2 | /* |
3 | * Sleepable Read-Copy Update mechanism for mutual exclusion, | |
4 | * tree variant. | |
5 | * | |
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6 | * Copyright (C) IBM Corporation, 2017 |
7 | * | |
8c366db0 | 8 | * Author: Paul McKenney <paulmck@linux.ibm.com> |
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9 | */ |
10 | ||
11 | #ifndef _LINUX_SRCU_TREE_H | |
12 | #define _LINUX_SRCU_TREE_H | |
13 | ||
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14 | #include <linux/rcu_node_tree.h> |
15 | #include <linux/completion.h> | |
16 | ||
17 | struct srcu_node; | |
18 | struct srcu_struct; | |
19 | ||
20 | /* | |
21 | * Per-CPU structure feeding into leaf srcu_node, similar in function | |
22 | * to rcu_node. | |
23 | */ | |
24 | struct srcu_data { | |
25 | /* Read-side state. */ | |
26 | unsigned long srcu_lock_count[2]; /* Locks per CPU. */ | |
27 | unsigned long srcu_unlock_count[2]; /* Unlocks per CPU. */ | |
28 | ||
29 | /* Update-side state. */ | |
d6331980 | 30 | spinlock_t __private lock ____cacheline_internodealigned_in_smp; |
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31 | struct rcu_segcblist srcu_cblist; /* List of callbacks.*/ |
32 | unsigned long srcu_gp_seq_needed; /* Furthest future GP needed. */ | |
1e9a038b | 33 | unsigned long srcu_gp_seq_needed_exp; /* Furthest future exp GP. */ |
da915ad5 | 34 | bool srcu_cblist_invoking; /* Invoking these CBs? */ |
e81baf4c SAS |
35 | struct timer_list delay_work; /* Delay for CB invoking */ |
36 | struct work_struct work; /* Context for CB invoking. */ | |
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37 | struct rcu_head srcu_barrier_head; /* For srcu_barrier() use. */ |
38 | struct srcu_node *mynode; /* Leaf srcu_node. */ | |
c7e88067 PM |
39 | unsigned long grpmask; /* Mask for leaf srcu_node */ |
40 | /* ->srcu_data_have_cbs[]. */ | |
da915ad5 | 41 | int cpu; |
aacb5d91 | 42 | struct srcu_struct *ssp; |
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43 | }; |
44 | ||
da915ad5 PM |
45 | /* |
46 | * Node in SRCU combining tree, similar in function to rcu_data. | |
47 | */ | |
48 | struct srcu_node { | |
d6331980 | 49 | spinlock_t __private lock; |
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50 | unsigned long srcu_have_cbs[4]; /* GP seq for children having CBs, but only */ |
51 | /* if greater than ->srcu_gq_seq. */ | |
52 | unsigned long srcu_data_have_cbs[4]; /* Which srcu_data structs have CBs for given GP? */ | |
1e9a038b | 53 | unsigned long srcu_gp_seq_needed_exp; /* Furthest future exp GP. */ |
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54 | struct srcu_node *srcu_parent; /* Next up in tree. */ |
55 | int grplo; /* Least CPU for node. */ | |
56 | int grphi; /* Biggest CPU for node. */ | |
57 | }; | |
58 | ||
59 | /* | |
60 | * Per-SRCU-domain structure, similar in function to rcu_state. | |
61 | */ | |
d8be8173 | 62 | struct srcu_struct { |
2ec30311 | 63 | struct srcu_node *node; /* Combining tree. */ |
da915ad5 PM |
64 | struct srcu_node *level[RCU_NUM_LVLS + 1]; |
65 | /* First node at each level. */ | |
994f7068 | 66 | int srcu_size_state; /* Small-to-big transition state. */ |
da915ad5 | 67 | struct mutex srcu_cb_mutex; /* Serialize CB preparation. */ |
994f7068 | 68 | spinlock_t __private lock; /* Protect counters and size state. */ |
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69 | struct mutex srcu_gp_mutex; /* Serialize GP work. */ |
70 | unsigned int srcu_idx; /* Current rdr array element. */ | |
71 | unsigned long srcu_gp_seq; /* Grace-period seq #. */ | |
72 | unsigned long srcu_gp_seq_needed; /* Latest gp_seq needed. */ | |
1e9a038b | 73 | unsigned long srcu_gp_seq_needed_exp; /* Furthest future exp GP. */ |
282d8998 | 74 | unsigned long srcu_gp_start; /* Last GP start timestamp (jiffies) */ |
22607d66 | 75 | unsigned long srcu_last_gp_end; /* Last GP end timestamp (ns) */ |
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76 | unsigned long srcu_size_jiffies; /* Current contention-measurement interval. */ |
77 | unsigned long srcu_n_lock_retries; /* Contention events in current interval. */ | |
282d8998 | 78 | unsigned long srcu_n_exp_nodelay; /* # expedited no-delays in current GP phase. */ |
da915ad5 | 79 | struct srcu_data __percpu *sda; /* Per-CPU srcu_data array. */ |
46470cf8 | 80 | bool sda_is_static; /* May ->sda be passed to free_percpu()? */ |
da915ad5 PM |
81 | unsigned long srcu_barrier_seq; /* srcu_barrier seq #. */ |
82 | struct mutex srcu_barrier_mutex; /* Serialize barrier ops. */ | |
83 | struct completion srcu_barrier_completion; | |
84 | /* Awaken barrier rq at end. */ | |
85 | atomic_t srcu_barrier_cpu_cnt; /* # CPUs not yet posting a */ | |
86 | /* callback for the barrier */ | |
87 | /* operation. */ | |
282d8998 PM |
88 | unsigned long reschedule_jiffies; |
89 | unsigned long reschedule_count; | |
d8be8173 | 90 | struct delayed_work work; |
d8be8173 | 91 | struct lockdep_map dep_map; |
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92 | }; |
93 | ||
994f7068 PM |
94 | /* Values for size state variable (->srcu_size_state). */ |
95 | #define SRCU_SIZE_SMALL 0 | |
96 | #define SRCU_SIZE_ALLOC 1 | |
97 | #define SRCU_SIZE_WAIT_BARRIER 2 | |
98 | #define SRCU_SIZE_WAIT_CALL 3 | |
99 | #define SRCU_SIZE_WAIT_CBS1 4 | |
100 | #define SRCU_SIZE_WAIT_CBS2 5 | |
101 | #define SRCU_SIZE_WAIT_CBS3 6 | |
102 | #define SRCU_SIZE_WAIT_CBS4 7 | |
103 | #define SRCU_SIZE_BIG 8 | |
104 | ||
da915ad5 | 105 | /* Values for state variable (bottom bits of ->srcu_gp_seq). */ |
d8be8173 PM |
106 | #define SRCU_STATE_IDLE 0 |
107 | #define SRCU_STATE_SCAN1 1 | |
108 | #define SRCU_STATE_SCAN2 2 | |
109 | ||
9c80172b | 110 | #define __SRCU_STRUCT_INIT(name, pcpu_name) \ |
e0fcba9a PM |
111 | { \ |
112 | .sda = &pcpu_name, \ | |
113 | .lock = __SPIN_LOCK_UNLOCKED(name.lock), \ | |
114 | .srcu_gp_seq_needed = -1UL, \ | |
4e6ea4ef | 115 | .work = __DELAYED_WORK_INITIALIZER(name.work, NULL, 0), \ |
e0fcba9a PM |
116 | __SRCU_DEP_MAP_INIT(name) \ |
117 | } | |
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118 | |
119 | /* | |
120 | * Define and initialize a srcu struct at build time. | |
121 | * Do -not- call init_srcu_struct() nor cleanup_srcu_struct() on it. | |
122 | * | |
123 | * Note that although DEFINE_STATIC_SRCU() hides the name from other | |
124 | * files, the per-CPU variable rules nevertheless require that the | |
125 | * chosen name be globally unique. These rules also prohibit use of | |
126 | * DEFINE_STATIC_SRCU() within a function. If these rules are too | |
127 | * restrictive, declare the srcu_struct manually. For example, in | |
128 | * each file: | |
129 | * | |
130 | * static struct srcu_struct my_srcu; | |
131 | * | |
132 | * Then, before the first use of each my_srcu, manually initialize it: | |
133 | * | |
134 | * init_srcu_struct(&my_srcu); | |
135 | * | |
136 | * See include/linux/percpu-defs.h for the rules on per-CPU variables. | |
137 | */ | |
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138 | #ifdef MODULE |
139 | # define __DEFINE_SRCU(name, is_static) \ | |
140 | is_static struct srcu_struct name; \ | |
db8f1471 | 141 | extern struct srcu_struct * const __srcu_struct_##name; \ |
056b89e7 | 142 | struct srcu_struct * const __srcu_struct_##name \ |
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143 | __section("___srcu_struct_ptrs") = &name |
144 | #else | |
145 | # define __DEFINE_SRCU(name, is_static) \ | |
146 | static DEFINE_PER_CPU(struct srcu_data, name##_srcu_data); \ | |
147 | is_static struct srcu_struct name = \ | |
148 | __SRCU_STRUCT_INIT(name, name##_srcu_data) | |
149 | #endif | |
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150 | #define DEFINE_SRCU(name) __DEFINE_SRCU(name, /* not static */) |
151 | #define DEFINE_STATIC_SRCU(name) __DEFINE_SRCU(name, static) | |
152 | ||
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153 | void synchronize_srcu_expedited(struct srcu_struct *ssp); |
154 | void srcu_barrier(struct srcu_struct *ssp); | |
155 | void srcu_torture_stats_print(struct srcu_struct *ssp, char *tt, char *tf); | |
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156 | |
157 | #endif |