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8c366db0 | 1 | /* SPDX-License-Identifier: GPL-2.0+ */ |
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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? */ |
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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. */ | |
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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 | ||
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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 */ |
51 | /* having CBs, but only */ | |
52 | /* is > ->srcu_gq_seq. */ | |
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53 | unsigned long srcu_data_have_cbs[4]; /* Which srcu_data structs */ |
54 | /* have CBs for given GP? */ | |
1e9a038b | 55 | unsigned long srcu_gp_seq_needed_exp; /* Furthest future exp GP. */ |
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56 | struct srcu_node *srcu_parent; /* Next up in tree. */ |
57 | int grplo; /* Least CPU for node. */ | |
58 | int grphi; /* Biggest CPU for node. */ | |
59 | }; | |
60 | ||
61 | /* | |
62 | * Per-SRCU-domain structure, similar in function to rcu_state. | |
63 | */ | |
d8be8173 | 64 | struct srcu_struct { |
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65 | struct srcu_node node[NUM_RCU_NODES]; /* Combining tree. */ |
66 | struct srcu_node *level[RCU_NUM_LVLS + 1]; | |
67 | /* First node at each level. */ | |
68 | struct mutex srcu_cb_mutex; /* Serialize CB preparation. */ | |
d6331980 | 69 | spinlock_t __private lock; /* Protect counters */ |
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70 | struct mutex srcu_gp_mutex; /* Serialize GP work. */ |
71 | unsigned int srcu_idx; /* Current rdr array element. */ | |
72 | unsigned long srcu_gp_seq; /* Grace-period seq #. */ | |
73 | unsigned long srcu_gp_seq_needed; /* Latest gp_seq needed. */ | |
1e9a038b | 74 | unsigned long srcu_gp_seq_needed_exp; /* Furthest future exp GP. */ |
22607d66 | 75 | unsigned long srcu_last_gp_end; /* Last GP end timestamp (ns) */ |
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76 | struct srcu_data __percpu *sda; /* Per-CPU srcu_data array. */ |
77 | unsigned long srcu_barrier_seq; /* srcu_barrier seq #. */ | |
78 | struct mutex srcu_barrier_mutex; /* Serialize barrier ops. */ | |
79 | struct completion srcu_barrier_completion; | |
80 | /* Awaken barrier rq at end. */ | |
81 | atomic_t srcu_barrier_cpu_cnt; /* # CPUs not yet posting a */ | |
82 | /* callback for the barrier */ | |
83 | /* operation. */ | |
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84 | struct delayed_work work; |
85 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
86 | struct lockdep_map dep_map; | |
87 | #endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ | |
88 | }; | |
89 | ||
da915ad5 | 90 | /* Values for state variable (bottom bits of ->srcu_gp_seq). */ |
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91 | #define SRCU_STATE_IDLE 0 |
92 | #define SRCU_STATE_SCAN1 1 | |
93 | #define SRCU_STATE_SCAN2 2 | |
94 | ||
9c80172b | 95 | #define __SRCU_STRUCT_INIT(name, pcpu_name) \ |
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96 | { \ |
97 | .sda = &pcpu_name, \ | |
98 | .lock = __SPIN_LOCK_UNLOCKED(name.lock), \ | |
99 | .srcu_gp_seq_needed = -1UL, \ | |
4e6ea4ef | 100 | .work = __DELAYED_WORK_INITIALIZER(name.work, NULL, 0), \ |
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101 | __SRCU_DEP_MAP_INIT(name) \ |
102 | } | |
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103 | |
104 | /* | |
105 | * Define and initialize a srcu struct at build time. | |
106 | * Do -not- call init_srcu_struct() nor cleanup_srcu_struct() on it. | |
107 | * | |
108 | * Note that although DEFINE_STATIC_SRCU() hides the name from other | |
109 | * files, the per-CPU variable rules nevertheless require that the | |
110 | * chosen name be globally unique. These rules also prohibit use of | |
111 | * DEFINE_STATIC_SRCU() within a function. If these rules are too | |
112 | * restrictive, declare the srcu_struct manually. For example, in | |
113 | * each file: | |
114 | * | |
115 | * static struct srcu_struct my_srcu; | |
116 | * | |
117 | * Then, before the first use of each my_srcu, manually initialize it: | |
118 | * | |
119 | * init_srcu_struct(&my_srcu); | |
120 | * | |
121 | * See include/linux/percpu-defs.h for the rules on per-CPU variables. | |
122 | */ | |
123 | #define __DEFINE_SRCU(name, is_static) \ | |
da915ad5 | 124 | static DEFINE_PER_CPU(struct srcu_data, name##_srcu_data);\ |
9c80172b | 125 | is_static struct srcu_struct name = __SRCU_STRUCT_INIT(name, name##_srcu_data) |
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126 | #define DEFINE_SRCU(name) __DEFINE_SRCU(name, /* not static */) |
127 | #define DEFINE_STATIC_SRCU(name) __DEFINE_SRCU(name, static) | |
128 | ||
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129 | void synchronize_srcu_expedited(struct srcu_struct *ssp); |
130 | void srcu_barrier(struct srcu_struct *ssp); | |
131 | void srcu_torture_stats_print(struct srcu_struct *ssp, char *tt, char *tf); | |
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132 | |
133 | #endif |