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wait_for_completion_*_timeout() can return: 0: if the wait timed out -ve: if the wait was interrupted +ve: if the completion was completed. As they currently return an 'unsigned long', the last two cases are not easily distinguished which can easily result in buggy code, as is the case for the recently added wait_for_completion_interruptible_timeout() call in net/sunrpc/cache.c So change them both to return 'long'. As MAX_SCHEDULE_TIMEOUT is LONG_MAX, a large +ve return value should never overflow. Signed-off-by: NeilBrown <neilb@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: J. Bruce Fields <bfields@fieldses.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> LKML-Reference: <20110105125016.64ccab0e@notabene.brown> Signed-off-by: Ingo Molnar <mingo@elte.hu>
105 lines
3.2 KiB
C
105 lines
3.2 KiB
C
#ifndef __LINUX_COMPLETION_H
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#define __LINUX_COMPLETION_H
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/*
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* (C) Copyright 2001 Linus Torvalds
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*
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* Atomic wait-for-completion handler data structures.
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* See kernel/sched.c for details.
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*/
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#include <linux/wait.h>
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/*
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* struct completion - structure used to maintain state for a "completion"
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*
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* This is the opaque structure used to maintain the state for a "completion".
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* Completions currently use a FIFO to queue threads that have to wait for
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* the "completion" event.
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*
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* See also: complete(), wait_for_completion() (and friends _timeout,
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* _interruptible, _interruptible_timeout, and _killable), init_completion(),
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* and macros DECLARE_COMPLETION(), DECLARE_COMPLETION_ONSTACK(), and
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* INIT_COMPLETION().
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*/
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struct completion {
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unsigned int done;
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wait_queue_head_t wait;
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};
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#define COMPLETION_INITIALIZER(work) \
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{ 0, __WAIT_QUEUE_HEAD_INITIALIZER((work).wait) }
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#define COMPLETION_INITIALIZER_ONSTACK(work) \
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({ init_completion(&work); work; })
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/**
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* DECLARE_COMPLETION - declare and initialize a completion structure
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* @work: identifier for the completion structure
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*
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* This macro declares and initializes a completion structure. Generally used
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* for static declarations. You should use the _ONSTACK variant for automatic
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* variables.
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*/
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#define DECLARE_COMPLETION(work) \
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struct completion work = COMPLETION_INITIALIZER(work)
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/*
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* Lockdep needs to run a non-constant initializer for on-stack
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* completions - so we use the _ONSTACK() variant for those that
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* are on the kernel stack:
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*/
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/**
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* DECLARE_COMPLETION_ONSTACK - declare and initialize a completion structure
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* @work: identifier for the completion structure
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*
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* This macro declares and initializes a completion structure on the kernel
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* stack.
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*/
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#ifdef CONFIG_LOCKDEP
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# define DECLARE_COMPLETION_ONSTACK(work) \
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struct completion work = COMPLETION_INITIALIZER_ONSTACK(work)
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#else
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# define DECLARE_COMPLETION_ONSTACK(work) DECLARE_COMPLETION(work)
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#endif
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/**
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* init_completion - Initialize a dynamically allocated completion
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* @x: completion structure that is to be initialized
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*
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* This inline function will initialize a dynamically created completion
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* structure.
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*/
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static inline void init_completion(struct completion *x)
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{
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x->done = 0;
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init_waitqueue_head(&x->wait);
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}
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extern void wait_for_completion(struct completion *);
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extern int wait_for_completion_interruptible(struct completion *x);
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extern int wait_for_completion_killable(struct completion *x);
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extern unsigned long wait_for_completion_timeout(struct completion *x,
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unsigned long timeout);
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extern long wait_for_completion_interruptible_timeout(
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struct completion *x, unsigned long timeout);
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extern long wait_for_completion_killable_timeout(
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struct completion *x, unsigned long timeout);
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extern bool try_wait_for_completion(struct completion *x);
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extern bool completion_done(struct completion *x);
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extern void complete(struct completion *);
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extern void complete_all(struct completion *);
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/**
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* INIT_COMPLETION - reinitialize a completion structure
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* @x: completion structure to be reinitialized
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*
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* This macro should be used to reinitialize a completion structure so it can
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* be reused. This is especially important after complete_all() is used.
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*/
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#define INIT_COMPLETION(x) ((x).done = 0)
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#endif
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