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authorTejun Heo <tj@kernel.org>2008-10-15 22:01:38 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-10-16 11:21:31 -0700
commita25d644fc0e232f242d1f3baa63c149c42536ff0 (patch)
treec5013caca7978d862f8ea1996c5933495fd7334a
parentc80cfb0406c01bb5da91bfe30f5cb1fd96831138 (diff)
wait: kill is_sync_wait()
is_sync_wait() is used to distinguish between sync and async waits. Basically sync waits are the ones initialized with init_waitqueue_entry() and async ones with init_waitqueue_func_entry(). The sync/async distinction is used only in prepare_to_wait[_exclusive]() and its only function is to skip setting the current task state if the wait is async. This has a few problems. * No one uses it. None of func_entry users use prepare_to_wait() functions, so the code path never gets executed. * The distinction is bogus. Maybe back when func_entry is used only by aio but it's now also used by epoll and in future possibly by 9p and poll/select. * Taking @state as argument and ignoring it silenly depending on how @wait is initialized is just a bad error-prone API. * It prevents func_entry waits from using wait->private for no good reason. This patch kills is_sync_wait() and the associated code paths from prepare_to_wait[_exclusive](). As there was no user of these code paths, this patch doesn't cause any behavior difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/wait.h9
-rw-r--r--kernel/wait.c14
2 files changed, 2 insertions, 21 deletions
diff --git a/include/linux/wait.h b/include/linux/wait.h
index 0081147a9fe8..ef609f842fac 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -108,15 +108,6 @@ static inline int waitqueue_active(wait_queue_head_t *q)
return !list_empty(&q->task_list);
}
-/*
- * Used to distinguish between sync and async io wait context:
- * sync i/o typically specifies a NULL wait queue entry or a wait
- * queue entry bound to a task (current task) to wake up.
- * aio specifies a wait queue entry with an async notification
- * callback routine, not associated with any task.
- */
-#define is_sync_wait(wait) (!(wait) || ((wait)->private))
-
extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait);
extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
diff --git a/kernel/wait.c b/kernel/wait.c
index c275c56cf2d3..cd87131f2fc2 100644
--- a/kernel/wait.c
+++ b/kernel/wait.c
@@ -72,12 +72,7 @@ prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state)
spin_lock_irqsave(&q->lock, flags);
if (list_empty(&wait->task_list))
__add_wait_queue(q, wait);
- /*
- * don't alter the task state if this is just going to
- * queue an async wait queue callback
- */
- if (is_sync_wait(wait))
- set_current_state(state);
+ set_current_state(state);
spin_unlock_irqrestore(&q->lock, flags);
}
EXPORT_SYMBOL(prepare_to_wait);
@@ -91,12 +86,7 @@ prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state)
spin_lock_irqsave(&q->lock, flags);
if (list_empty(&wait->task_list))
__add_wait_queue_tail(q, wait);
- /*
- * don't alter the task state if this is just going to
- * queue an async wait queue callback
- */
- if (is_sync_wait(wait))
- set_current_state(state);
+ set_current_state(state);
spin_unlock_irqrestore(&q->lock, flags);
}
EXPORT_SYMBOL(prepare_to_wait_exclusive);

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