![Oleg Nesterov](/assets/img/avatar_default.png)
As pointed out by Jarek Poplawski, the patch
[WORKQUEUE]: cancel_delayed_work: use del_timer() instead of del_timer_sync()
commit: 071b638689
was wrong, it was merged by mistake after that.
From the changelog:
after this patch:
...
delayed_work_timer_fn->__queue_work() in progress.
The latter doesn't differ from the caller's POV,
it does make a difference if the caller calls flush_workqueue() after
cancel_delayed_work(), in that case flush_workqueue() can miss this
work_struct.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Jarek Poplawski <jarkao2@o2.pl>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
180 lines
4.9 KiB
C
180 lines
4.9 KiB
C
/*
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* workqueue.h --- work queue handling for Linux.
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*/
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#ifndef _LINUX_WORKQUEUE_H
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#define _LINUX_WORKQUEUE_H
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#include <linux/timer.h>
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#include <linux/linkage.h>
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#include <linux/bitops.h>
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#include <asm/atomic.h>
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struct workqueue_struct;
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struct work_struct;
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typedef void (*work_func_t)(struct work_struct *work);
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/*
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* The first word is the work queue pointer and the flags rolled into
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* one
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*/
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#define work_data_bits(work) ((unsigned long *)(&(work)->data))
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struct work_struct {
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atomic_long_t data;
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#define WORK_STRUCT_PENDING 0 /* T if work item pending execution */
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#define WORK_STRUCT_FLAG_MASK (3UL)
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#define WORK_STRUCT_WQ_DATA_MASK (~WORK_STRUCT_FLAG_MASK)
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struct list_head entry;
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work_func_t func;
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};
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#define WORK_DATA_INIT() ATOMIC_LONG_INIT(0)
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struct delayed_work {
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struct work_struct work;
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struct timer_list timer;
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};
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struct execute_work {
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struct work_struct work;
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};
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#define __WORK_INITIALIZER(n, f) { \
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.data = WORK_DATA_INIT(), \
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.entry = { &(n).entry, &(n).entry }, \
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.func = (f), \
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}
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#define __DELAYED_WORK_INITIALIZER(n, f) { \
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.work = __WORK_INITIALIZER((n).work, (f)), \
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.timer = TIMER_INITIALIZER(NULL, 0, 0), \
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}
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#define DECLARE_WORK(n, f) \
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struct work_struct n = __WORK_INITIALIZER(n, f)
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#define DECLARE_DELAYED_WORK(n, f) \
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struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f)
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/*
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* initialize a work item's function pointer
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*/
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#define PREPARE_WORK(_work, _func) \
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do { \
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(_work)->func = (_func); \
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} while (0)
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#define PREPARE_DELAYED_WORK(_work, _func) \
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PREPARE_WORK(&(_work)->work, (_func))
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/*
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* initialize all of a work item in one go
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*
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* NOTE! No point in using "atomic_long_set()": useing a direct
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* assignment of the work data initializer allows the compiler
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* to generate better code.
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*/
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#define INIT_WORK(_work, _func) \
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do { \
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(_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
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INIT_LIST_HEAD(&(_work)->entry); \
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PREPARE_WORK((_work), (_func)); \
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} while (0)
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#define INIT_DELAYED_WORK(_work, _func) \
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do { \
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INIT_WORK(&(_work)->work, (_func)); \
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init_timer(&(_work)->timer); \
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} while (0)
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#define INIT_DELAYED_WORK_DEFERRABLE(_work, _func) \
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do { \
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INIT_WORK(&(_work)->work, (_func)); \
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init_timer_deferrable(&(_work)->timer); \
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} while (0)
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/**
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* work_pending - Find out whether a work item is currently pending
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* @work: The work item in question
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*/
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#define work_pending(work) \
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test_bit(WORK_STRUCT_PENDING, work_data_bits(work))
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/**
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* delayed_work_pending - Find out whether a delayable work item is currently
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* pending
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* @work: The work item in question
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*/
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#define delayed_work_pending(w) \
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work_pending(&(w)->work)
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/**
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* work_clear_pending - for internal use only, mark a work item as not pending
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* @work: The work item in question
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*/
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#define work_clear_pending(work) \
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clear_bit(WORK_STRUCT_PENDING, work_data_bits(work))
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extern struct workqueue_struct *__create_workqueue(const char *name,
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int singlethread,
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int freezeable);
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#define create_workqueue(name) __create_workqueue((name), 0, 0)
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#define create_freezeable_workqueue(name) __create_workqueue((name), 1, 1)
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#define create_singlethread_workqueue(name) __create_workqueue((name), 1, 0)
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extern void destroy_workqueue(struct workqueue_struct *wq);
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extern int FASTCALL(queue_work(struct workqueue_struct *wq, struct work_struct *work));
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extern int FASTCALL(queue_delayed_work(struct workqueue_struct *wq,
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struct delayed_work *work, unsigned long delay));
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extern int queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
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struct delayed_work *work, unsigned long delay);
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extern void FASTCALL(flush_workqueue(struct workqueue_struct *wq));
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extern void flush_scheduled_work(void);
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extern int FASTCALL(schedule_work(struct work_struct *work));
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extern int FASTCALL(schedule_delayed_work(struct delayed_work *work,
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unsigned long delay));
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extern int schedule_delayed_work_on(int cpu, struct delayed_work *work,
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unsigned long delay);
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extern int schedule_on_each_cpu(work_func_t func);
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extern int current_is_keventd(void);
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extern int keventd_up(void);
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extern void init_workqueues(void);
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int execute_in_process_context(work_func_t fn, struct execute_work *);
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extern void cancel_work_sync(struct work_struct *work);
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/*
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* Kill off a pending schedule_delayed_work(). Note that the work callback
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* function may still be running on return from cancel_delayed_work(), unless
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* it returns 1 and the work doesn't re-arm itself. Run flush_workqueue() or
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* cancel_work_sync() to wait on it.
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*/
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static inline int cancel_delayed_work(struct delayed_work *work)
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{
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int ret;
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ret = del_timer_sync(&work->timer);
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if (ret)
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work_clear_pending(&work->work);
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return ret;
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}
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extern void cancel_rearming_delayed_work(struct delayed_work *work);
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/* Obsolete. use cancel_rearming_delayed_work() */
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static inline
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void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq,
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struct delayed_work *work)
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{
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cancel_rearming_delayed_work(work);
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}
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#endif
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