/* SPDX-License-Identifier: GPL-2.0 */ /* * workqueue.h --- work queue handling for Linux. */ #ifndef _LINUX_WORKQUEUE_H #define _LINUX_WORKQUEUE_H #include <linux/timer.h> #include <linux/linkage.h> #include <linux/bitops.h> #include <linux/lockdep.h> #include <linux/threads.h> #include <linux/atomic.h> #include <linux/cpumask_types.h> #include <linux/rcupdate.h> #include <linux/workqueue_types.h> /* * The first word is the work queue pointer and the flags rolled into * one */ #define work_data_bits(work) … enum work_bits { … }; enum work_flags { … }; enum wq_misc_consts { … }; /* Convenience constants - of type 'unsigned long', not 'enum'! */ #define WORK_OFFQ_BH … #define WORK_OFFQ_FLAG_MASK … #define WORK_OFFQ_DISABLE_MASK … #define WORK_OFFQ_POOL_NONE … #define WORK_STRUCT_NO_POOL … #define WORK_STRUCT_PWQ_MASK … #define WORK_DATA_INIT() … #define WORK_DATA_STATIC_INIT() … struct delayed_work { … }; struct rcu_work { … }; enum wq_affn_scope { … }; /** * struct workqueue_attrs - A struct for workqueue attributes. * * This can be used to change attributes of an unbound workqueue. */ struct workqueue_attrs { … }; static inline struct delayed_work *to_delayed_work(struct work_struct *work) { … } static inline struct rcu_work *to_rcu_work(struct work_struct *work) { … } struct execute_work { … }; #ifdef CONFIG_LOCKDEP /* * NB: because we have to copy the lockdep_map, setting _key * here is required, otherwise it could get initialised to the * copy of the lockdep_map! */ #define __WORK_INIT_LOCKDEP_MAP(n, k) … #else #define __WORK_INIT_LOCKDEP_MAP … #endif #define __WORK_INITIALIZER(n, f) … #define __DELAYED_WORK_INITIALIZER(n, f, tflags) … #define DECLARE_WORK(n, f) … #define DECLARE_DELAYED_WORK(n, f) … #define DECLARE_DEFERRABLE_WORK(n, f) … #ifdef CONFIG_DEBUG_OBJECTS_WORK extern void __init_work(struct work_struct *work, int onstack); extern void destroy_work_on_stack(struct work_struct *work); extern void destroy_delayed_work_on_stack(struct delayed_work *work); static inline unsigned int work_static(struct work_struct *work) { … } #else static inline void __init_work(struct work_struct *work, int onstack) { } static inline void destroy_work_on_stack(struct work_struct *work) { } static inline void destroy_delayed_work_on_stack(struct delayed_work *work) { } static inline unsigned int work_static(struct work_struct *work) { return 0; } #endif /* * initialize all of a work item in one go * * NOTE! No point in using "atomic_long_set()": using a direct * assignment of the work data initializer allows the compiler * to generate better code. */ #ifdef CONFIG_LOCKDEP #define __INIT_WORK_KEY(_work, _func, _onstack, _key) … #else #define __INIT_WORK_KEY … #endif #define __INIT_WORK(_work, _func, _onstack) … #define INIT_WORK(_work, _func) … #define INIT_WORK_ONSTACK(_work, _func) … #define INIT_WORK_ONSTACK_KEY(_work, _func, _key) … #define __INIT_DELAYED_WORK(_work, _func, _tflags) … #define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags) … #define INIT_DELAYED_WORK(_work, _func) … #define INIT_DELAYED_WORK_ONSTACK(_work, _func) … #define INIT_DEFERRABLE_WORK(_work, _func) … #define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func) … #define INIT_RCU_WORK(_work, _func) … #define INIT_RCU_WORK_ONSTACK(_work, _func) … /** * work_pending - Find out whether a work item is currently pending * @work: The work item in question */ #define work_pending(work) … /** * delayed_work_pending - Find out whether a delayable work item is currently * pending * @w: The work item in question */ #define delayed_work_pending(w) … /* * Workqueue flags and constants. For details, please refer to * Documentation/core-api/workqueue.rst. */ enum wq_flags { … }; enum wq_consts { … }; /* * System-wide workqueues which are always present. * * system_wq is the one used by schedule[_delayed]_work[_on](). * Multi-CPU multi-threaded. There are users which expect relatively * short queue flush time. Don't queue works which can run for too * long. * * system_highpri_wq is similar to system_wq but for work items which * require WQ_HIGHPRI. * * system_long_wq is similar to system_wq but may host long running * works. Queue flushing might take relatively long. * * system_unbound_wq is unbound workqueue. Workers are not bound to * any specific CPU, not concurrency managed, and all queued works are * executed immediately as long as max_active limit is not reached and * resources are available. * * system_freezable_wq is equivalent to system_wq except that it's * freezable. * * *_power_efficient_wq are inclined towards saving power and converted * into WQ_UNBOUND variants if 'wq_power_efficient' is enabled; otherwise, * they are same as their non-power-efficient counterparts - e.g. * system_power_efficient_wq is identical to system_wq if * 'wq_power_efficient' is disabled. See WQ_POWER_EFFICIENT for more info. * * system_bh[_highpri]_wq are convenience interface to softirq. BH work items * are executed in the queueing CPU's BH context in the queueing order. */ extern struct workqueue_struct *system_wq; extern struct workqueue_struct *system_highpri_wq; extern struct workqueue_struct *system_long_wq; extern struct workqueue_struct *system_unbound_wq; extern struct workqueue_struct *system_freezable_wq; extern struct workqueue_struct *system_power_efficient_wq; extern struct workqueue_struct *system_freezable_power_efficient_wq; extern struct workqueue_struct *system_bh_wq; extern struct workqueue_struct *system_bh_highpri_wq; void workqueue_softirq_action(bool highpri); void workqueue_softirq_dead(unsigned int cpu); /** * alloc_workqueue - allocate a workqueue * @fmt: printf format for the name of the workqueue * @flags: WQ_* flags * @max_active: max in-flight work items, 0 for default * @...: args for @fmt * * For a per-cpu workqueue, @max_active limits the number of in-flight work * items for each CPU. e.g. @max_active of 1 indicates that each CPU can be * executing at most one work item for the workqueue. * * For unbound workqueues, @max_active limits the number of in-flight work items * for the whole system. e.g. @max_active of 16 indicates that that there can be * at most 16 work items executing for the workqueue in the whole system. * * As sharing the same active counter for an unbound workqueue across multiple * NUMA nodes can be expensive, @max_active is distributed to each NUMA node * according to the proportion of the number of online CPUs and enforced * independently. * * Depending on online CPU distribution, a node may end up with per-node * max_active which is significantly lower than @max_active, which can lead to * deadlocks if the per-node concurrency limit is lower than the maximum number * of interdependent work items for the workqueue. * * To guarantee forward progress regardless of online CPU distribution, the * concurrency limit on every node is guaranteed to be equal to or greater than * min_active which is set to min(@max_active, %WQ_DFL_MIN_ACTIVE). This means * that the sum of per-node max_active's may be larger than @max_active. * * For detailed information on %WQ_* flags, please refer to * Documentation/core-api/workqueue.rst. * * RETURNS: * Pointer to the allocated workqueue on success, %NULL on failure. */ __printf(1, 4) struct workqueue_struct * alloc_workqueue(const char *fmt, unsigned int flags, int max_active, ...); /** * alloc_ordered_workqueue - allocate an ordered workqueue * @fmt: printf format for the name of the workqueue * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful) * @args: args for @fmt * * Allocate an ordered workqueue. An ordered workqueue executes at * most one work item at any given time in the queued order. They are * implemented as unbound workqueues with @max_active of one. * * RETURNS: * Pointer to the allocated workqueue on success, %NULL on failure. */ #define alloc_ordered_workqueue(fmt, flags, args...) … #define create_workqueue(name) … #define create_freezable_workqueue(name) … #define create_singlethread_workqueue(name) … #define from_work(var, callback_work, work_fieldname) … extern void destroy_workqueue(struct workqueue_struct *wq); struct workqueue_attrs *alloc_workqueue_attrs(void); void free_workqueue_attrs(struct workqueue_attrs *attrs); int apply_workqueue_attrs(struct workqueue_struct *wq, const struct workqueue_attrs *attrs); extern int workqueue_unbound_exclude_cpumask(cpumask_var_t cpumask); extern bool queue_work_on(int cpu, struct workqueue_struct *wq, struct work_struct *work); extern bool queue_work_node(int node, struct workqueue_struct *wq, struct work_struct *work); extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq, struct delayed_work *work, unsigned long delay); extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq, struct delayed_work *dwork, unsigned long delay); extern bool queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork); extern void __flush_workqueue(struct workqueue_struct *wq); extern void drain_workqueue(struct workqueue_struct *wq); extern int schedule_on_each_cpu(work_func_t func); int execute_in_process_context(work_func_t fn, struct execute_work *); extern bool flush_work(struct work_struct *work); extern bool cancel_work(struct work_struct *work); extern bool cancel_work_sync(struct work_struct *work); extern bool flush_delayed_work(struct delayed_work *dwork); extern bool cancel_delayed_work(struct delayed_work *dwork); extern bool cancel_delayed_work_sync(struct delayed_work *dwork); extern bool disable_work(struct work_struct *work); extern bool disable_work_sync(struct work_struct *work); extern bool enable_work(struct work_struct *work); extern bool disable_delayed_work(struct delayed_work *dwork); extern bool disable_delayed_work_sync(struct delayed_work *dwork); extern bool enable_delayed_work(struct delayed_work *dwork); extern bool flush_rcu_work(struct rcu_work *rwork); extern void workqueue_set_max_active(struct workqueue_struct *wq, int max_active); extern void workqueue_set_min_active(struct workqueue_struct *wq, int min_active); extern struct work_struct *current_work(void); extern bool current_is_workqueue_rescuer(void); extern bool workqueue_congested(int cpu, struct workqueue_struct *wq); extern unsigned int work_busy(struct work_struct *work); extern __printf(1, 2) void set_worker_desc(const char *fmt, ...); extern void print_worker_info(const char *log_lvl, struct task_struct *task); extern void show_all_workqueues(void); extern void show_freezable_workqueues(void); extern void show_one_workqueue(struct workqueue_struct *wq); extern void wq_worker_comm(char *buf, size_t size, struct task_struct *task); /** * queue_work - queue work on a workqueue * @wq: workqueue to use * @work: work to queue * * Returns %false if @work was already on a queue, %true otherwise. * * We queue the work to the CPU on which it was submitted, but if the CPU dies * it can be processed by another CPU. * * Memory-ordering properties: If it returns %true, guarantees that all stores * preceding the call to queue_work() in the program order will be visible from * the CPU which will execute @work by the time such work executes, e.g., * * { x is initially 0 } * * CPU0 CPU1 * * WRITE_ONCE(x, 1); [ @work is being executed ] * r0 = queue_work(wq, work); r1 = READ_ONCE(x); * * Forbids: r0 == true && r1 == 0 */ static inline bool queue_work(struct workqueue_struct *wq, struct work_struct *work) { … } /** * queue_delayed_work - queue work on a workqueue after delay * @wq: workqueue to use * @dwork: delayable work to queue * @delay: number of jiffies to wait before queueing * * Equivalent to queue_delayed_work_on() but tries to use the local CPU. */ static inline bool queue_delayed_work(struct workqueue_struct *wq, struct delayed_work *dwork, unsigned long delay) { … } /** * mod_delayed_work - modify delay of or queue a delayed work * @wq: workqueue to use * @dwork: work to queue * @delay: number of jiffies to wait before queueing * * mod_delayed_work_on() on local CPU. */ static inline bool mod_delayed_work(struct workqueue_struct *wq, struct delayed_work *dwork, unsigned long delay) { … } /** * schedule_work_on - put work task on a specific cpu * @cpu: cpu to put the work task on * @work: job to be done * * This puts a job on a specific cpu */ static inline bool schedule_work_on(int cpu, struct work_struct *work) { … } /** * schedule_work - put work task in global workqueue * @work: job to be done * * Returns %false if @work was already on the kernel-global workqueue and * %true otherwise. * * This puts a job in the kernel-global workqueue if it was not already * queued and leaves it in the same position on the kernel-global * workqueue otherwise. * * Shares the same memory-ordering properties of queue_work(), cf. the * DocBook header of queue_work(). */ static inline bool schedule_work(struct work_struct *work) { … } /** * enable_and_queue_work - Enable and queue a work item on a specific workqueue * @wq: The target workqueue * @work: The work item to be enabled and queued * * This function combines the operations of enable_work() and queue_work(), * providing a convenient way to enable and queue a work item in a single call. * It invokes enable_work() on @work and then queues it if the disable depth * reached 0. Returns %true if the disable depth reached 0 and @work is queued, * and %false otherwise. * * Note that @work is always queued when disable depth reaches zero. If the * desired behavior is queueing only if certain events took place while @work is * disabled, the user should implement the necessary state tracking and perform * explicit conditional queueing after enable_work(). */ static inline bool enable_and_queue_work(struct workqueue_struct *wq, struct work_struct *work) { … } /* * Detect attempt to flush system-wide workqueues at compile time when possible. * Warn attempt to flush system-wide workqueues at runtime. * * See https://lkml.kernel.org/r/[email protected] * for reasons and steps for converting system-wide workqueues into local workqueues. */ extern void __warn_flushing_systemwide_wq(void) __compiletime_warning("Please avoid flushing system-wide workqueues."); /* Please stop using this function, for this function will be removed in near future. */ #define flush_scheduled_work() … #define flush_workqueue(wq) … /** * schedule_delayed_work_on - queue work in global workqueue on CPU after delay * @cpu: cpu to use * @dwork: job to be done * @delay: number of jiffies to wait * * After waiting for a given time this puts a job in the kernel-global * workqueue on the specified CPU. */ static inline bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork, unsigned long delay) { … } /** * schedule_delayed_work - put work task in global workqueue after delay * @dwork: job to be done * @delay: number of jiffies to wait or 0 for immediate execution * * After waiting for a given time this puts a job in the kernel-global * workqueue. */ static inline bool schedule_delayed_work(struct delayed_work *dwork, unsigned long delay) { … } #ifndef CONFIG_SMP static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg) { return fn(arg); } static inline long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg) { return fn(arg); } #else long work_on_cpu_key(int cpu, long (*fn)(void *), void *arg, struct lock_class_key *key); /* * A new key is defined for each caller to make sure the work * associated with the function doesn't share its locking class. */ #define work_on_cpu(_cpu, _fn, _arg) … long work_on_cpu_safe_key(int cpu, long (*fn)(void *), void *arg, struct lock_class_key *key); /* * A new key is defined for each caller to make sure the work * associated with the function doesn't share its locking class. */ #define work_on_cpu_safe(_cpu, _fn, _arg) … #endif /* CONFIG_SMP */ #ifdef CONFIG_FREEZER extern void freeze_workqueues_begin(void); extern bool freeze_workqueues_busy(void); extern void thaw_workqueues(void); #endif /* CONFIG_FREEZER */ #ifdef CONFIG_SYSFS int workqueue_sysfs_register(struct workqueue_struct *wq); #else /* CONFIG_SYSFS */ static inline int workqueue_sysfs_register(struct workqueue_struct *wq) { return 0; } #endif /* CONFIG_SYSFS */ #ifdef CONFIG_WQ_WATCHDOG void wq_watchdog_touch(int cpu); #else /* CONFIG_WQ_WATCHDOG */ static inline void wq_watchdog_touch(int cpu) { } #endif /* CONFIG_WQ_WATCHDOG */ #ifdef CONFIG_SMP int workqueue_prepare_cpu(unsigned int cpu); int workqueue_online_cpu(unsigned int cpu); int workqueue_offline_cpu(unsigned int cpu); #endif void __init workqueue_init_early(void); void __init workqueue_init(void); void __init workqueue_init_topology(void); #endif
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