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141 lines
4.9 KiB
141 lines
4.9 KiB
/* SPDX-License-Identifier: GPL-2.0+ */ |
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/* |
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* Sleepable Read-Copy Update mechanism for mutual exclusion, |
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* tree variant. |
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* |
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* Copyright (C) IBM Corporation, 2017 |
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* |
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* Author: Paul McKenney <[email protected]> |
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*/ |
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#ifndef _LINUX_SRCU_TREE_H |
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#define _LINUX_SRCU_TREE_H |
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#include <linux/rcu_node_tree.h> |
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#include <linux/completion.h> |
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struct srcu_node; |
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struct srcu_struct; |
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/* |
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* Per-CPU structure feeding into leaf srcu_node, similar in function |
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* to rcu_node. |
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*/ |
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struct srcu_data { |
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/* Read-side state. */ |
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unsigned long srcu_lock_count[2]; /* Locks per CPU. */ |
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unsigned long srcu_unlock_count[2]; /* Unlocks per CPU. */ |
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/* Update-side state. */ |
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spinlock_t __private lock ____cacheline_internodealigned_in_smp; |
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struct rcu_segcblist srcu_cblist; /* List of callbacks.*/ |
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unsigned long srcu_gp_seq_needed; /* Furthest future GP needed. */ |
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unsigned long srcu_gp_seq_needed_exp; /* Furthest future exp GP. */ |
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bool srcu_cblist_invoking; /* Invoking these CBs? */ |
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struct timer_list delay_work; /* Delay for CB invoking */ |
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struct work_struct work; /* Context for CB invoking. */ |
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struct rcu_head srcu_barrier_head; /* For srcu_barrier() use. */ |
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struct srcu_node *mynode; /* Leaf srcu_node. */ |
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unsigned long grpmask; /* Mask for leaf srcu_node */ |
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/* ->srcu_data_have_cbs[]. */ |
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int cpu; |
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struct srcu_struct *ssp; |
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}; |
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/* |
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* Node in SRCU combining tree, similar in function to rcu_data. |
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*/ |
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struct srcu_node { |
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spinlock_t __private lock; |
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unsigned long srcu_have_cbs[4]; /* GP seq for children */ |
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/* having CBs, but only */ |
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/* is > ->srcu_gq_seq. */ |
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unsigned long srcu_data_have_cbs[4]; /* Which srcu_data structs */ |
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/* have CBs for given GP? */ |
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unsigned long srcu_gp_seq_needed_exp; /* Furthest future exp GP. */ |
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struct srcu_node *srcu_parent; /* Next up in tree. */ |
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int grplo; /* Least CPU for node. */ |
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int grphi; /* Biggest CPU for node. */ |
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}; |
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/* |
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* Per-SRCU-domain structure, similar in function to rcu_state. |
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*/ |
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struct srcu_struct { |
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struct srcu_node node[NUM_RCU_NODES]; /* Combining tree. */ |
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struct srcu_node *level[RCU_NUM_LVLS + 1]; |
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/* First node at each level. */ |
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struct mutex srcu_cb_mutex; /* Serialize CB preparation. */ |
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spinlock_t __private lock; /* Protect counters */ |
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struct mutex srcu_gp_mutex; /* Serialize GP work. */ |
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unsigned int srcu_idx; /* Current rdr array element. */ |
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unsigned long srcu_gp_seq; /* Grace-period seq #. */ |
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unsigned long srcu_gp_seq_needed; /* Latest gp_seq needed. */ |
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unsigned long srcu_gp_seq_needed_exp; /* Furthest future exp GP. */ |
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unsigned long srcu_last_gp_end; /* Last GP end timestamp (ns) */ |
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struct srcu_data __percpu *sda; /* Per-CPU srcu_data array. */ |
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unsigned long srcu_barrier_seq; /* srcu_barrier seq #. */ |
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struct mutex srcu_barrier_mutex; /* Serialize barrier ops. */ |
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struct completion srcu_barrier_completion; |
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/* Awaken barrier rq at end. */ |
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atomic_t srcu_barrier_cpu_cnt; /* # CPUs not yet posting a */ |
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/* callback for the barrier */ |
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/* operation. */ |
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struct delayed_work work; |
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#ifdef CONFIG_DEBUG_LOCK_ALLOC |
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struct lockdep_map dep_map; |
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#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ |
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}; |
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/* Values for state variable (bottom bits of ->srcu_gp_seq). */ |
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#define SRCU_STATE_IDLE 0 |
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#define SRCU_STATE_SCAN1 1 |
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#define SRCU_STATE_SCAN2 2 |
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#define __SRCU_STRUCT_INIT(name, pcpu_name) \ |
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{ \ |
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.sda = &pcpu_name, \ |
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.lock = __SPIN_LOCK_UNLOCKED(name.lock), \ |
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.srcu_gp_seq_needed = -1UL, \ |
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.work = __DELAYED_WORK_INITIALIZER(name.work, NULL, 0), \ |
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__SRCU_DEP_MAP_INIT(name) \ |
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} |
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/* |
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* Define and initialize a srcu struct at build time. |
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* Do -not- call init_srcu_struct() nor cleanup_srcu_struct() on it. |
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* |
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* Note that although DEFINE_STATIC_SRCU() hides the name from other |
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* files, the per-CPU variable rules nevertheless require that the |
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* chosen name be globally unique. These rules also prohibit use of |
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* DEFINE_STATIC_SRCU() within a function. If these rules are too |
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* restrictive, declare the srcu_struct manually. For example, in |
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* each file: |
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* |
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* static struct srcu_struct my_srcu; |
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* |
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* Then, before the first use of each my_srcu, manually initialize it: |
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* |
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* init_srcu_struct(&my_srcu); |
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* |
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* See include/linux/percpu-defs.h for the rules on per-CPU variables. |
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*/ |
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#ifdef MODULE |
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# define __DEFINE_SRCU(name, is_static) \ |
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is_static struct srcu_struct name; \ |
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struct srcu_struct * const __srcu_struct_##name \ |
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__section("___srcu_struct_ptrs") = &name |
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#else |
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# define __DEFINE_SRCU(name, is_static) \ |
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static DEFINE_PER_CPU(struct srcu_data, name##_srcu_data); \ |
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is_static struct srcu_struct name = \ |
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__SRCU_STRUCT_INIT(name, name##_srcu_data) |
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#endif |
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#define DEFINE_SRCU(name) __DEFINE_SRCU(name, /* not static */) |
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#define DEFINE_STATIC_SRCU(name) __DEFINE_SRCU(name, static) |
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void synchronize_srcu_expedited(struct srcu_struct *ssp); |
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void srcu_barrier(struct srcu_struct *ssp); |
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void srcu_torture_stats_print(struct srcu_struct *ssp, char *tt, char *tf); |
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#endif
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