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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 | /* * Sleepable Read-Copy Update mechanism for mutual exclusion, * tree variant. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, you can access it online at * http://www.gnu.org/licenses/gpl-2.0.html. * * Copyright (C) IBM Corporation, 2017 * * Author: Paul McKenney <paulmck@us.ibm.com> */ #ifndef _LINUX_SRCU_TREE_H #define _LINUX_SRCU_TREE_H #include <linux/rcu_node_tree.h> #include <linux/completion.h> struct srcu_node; struct srcu_struct; /* * Per-CPU structure feeding into leaf srcu_node, similar in function * to rcu_node. */ struct srcu_data { /* Read-side state. */ unsigned long srcu_lock_count[2]; /* Locks per CPU. */ unsigned long srcu_unlock_count[2]; /* Unlocks per CPU. */ /* Update-side state. */ spinlock_t __private lock ____cacheline_internodealigned_in_smp; struct rcu_segcblist srcu_cblist; /* List of callbacks.*/ unsigned long srcu_gp_seq_needed; /* Furthest future GP needed. */ unsigned long srcu_gp_seq_needed_exp; /* Furthest future exp GP. */ bool srcu_cblist_invoking; /* Invoking these CBs? */ struct delayed_work work; /* Context for CB invoking. */ struct rcu_head srcu_barrier_head; /* For srcu_barrier() use. */ struct srcu_node *mynode; /* Leaf srcu_node. */ unsigned long grpmask; /* Mask for leaf srcu_node */ /* ->srcu_data_have_cbs[]. */ int cpu; struct srcu_struct *sp; }; /* * Node in SRCU combining tree, similar in function to rcu_data. */ struct srcu_node { spinlock_t __private lock; unsigned long srcu_have_cbs[4]; /* GP seq for children */ /* having CBs, but only */ /* is > ->srcu_gq_seq. */ unsigned long srcu_data_have_cbs[4]; /* Which srcu_data structs */ /* have CBs for given GP? */ unsigned long srcu_gp_seq_needed_exp; /* Furthest future exp GP. */ struct srcu_node *srcu_parent; /* Next up in tree. */ int grplo; /* Least CPU for node. */ int grphi; /* Biggest CPU for node. */ }; /* * Per-SRCU-domain structure, similar in function to rcu_state. */ struct srcu_struct { struct srcu_node node[NUM_RCU_NODES]; /* Combining tree. */ struct srcu_node *level[RCU_NUM_LVLS + 1]; /* First node at each level. */ struct mutex srcu_cb_mutex; /* Serialize CB preparation. */ spinlock_t __private lock; /* Protect counters */ struct mutex srcu_gp_mutex; /* Serialize GP work. */ unsigned int srcu_idx; /* Current rdr array element. */ unsigned long srcu_gp_seq; /* Grace-period seq #. */ unsigned long srcu_gp_seq_needed; /* Latest gp_seq needed. */ unsigned long srcu_gp_seq_needed_exp; /* Furthest future exp GP. */ unsigned long srcu_last_gp_end; /* Last GP end timestamp (ns) */ struct srcu_data __percpu *sda; /* Per-CPU srcu_data array. */ unsigned long srcu_barrier_seq; /* srcu_barrier seq #. */ struct mutex srcu_barrier_mutex; /* Serialize barrier ops. */ struct completion srcu_barrier_completion; /* Awaken barrier rq at end. */ atomic_t srcu_barrier_cpu_cnt; /* # CPUs not yet posting a */ /* callback for the barrier */ /* operation. */ struct delayed_work work; #ifdef CONFIG_DEBUG_LOCK_ALLOC struct lockdep_map dep_map; #endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ }; /* Values for state variable (bottom bits of ->srcu_gp_seq). */ #define SRCU_STATE_IDLE 0 #define SRCU_STATE_SCAN1 1 #define SRCU_STATE_SCAN2 2 #define __SRCU_STRUCT_INIT(name, pcpu_name) \ { \ .sda = &pcpu_name, \ .lock = __SPIN_LOCK_UNLOCKED(name.lock), \ .srcu_gp_seq_needed = 0 - 1, \ __SRCU_DEP_MAP_INIT(name) \ } /* * Define and initialize a srcu struct at build time. * Do -not- call init_srcu_struct() nor cleanup_srcu_struct() on it. * * Note that although DEFINE_STATIC_SRCU() hides the name from other * files, the per-CPU variable rules nevertheless require that the * chosen name be globally unique. These rules also prohibit use of * DEFINE_STATIC_SRCU() within a function. If these rules are too * restrictive, declare the srcu_struct manually. For example, in * each file: * * static struct srcu_struct my_srcu; * * Then, before the first use of each my_srcu, manually initialize it: * * init_srcu_struct(&my_srcu); * * See include/linux/percpu-defs.h for the rules on per-CPU variables. */ #define __DEFINE_SRCU(name, is_static) \ static DEFINE_PER_CPU(struct srcu_data, name##_srcu_data);\ is_static struct srcu_struct name = __SRCU_STRUCT_INIT(name, name##_srcu_data) #define DEFINE_SRCU(name) __DEFINE_SRCU(name, /* not static */) #define DEFINE_STATIC_SRCU(name) __DEFINE_SRCU(name, static) void synchronize_srcu_expedited(struct srcu_struct *sp); void srcu_barrier(struct srcu_struct *sp); void srcu_torture_stats_print(struct srcu_struct *sp, char *tt, char *tf); #endif |