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SLOW_WORK: Make slow_work_ops ->get_ref/->put_ref optional

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Make the ability for the slow-work facility to take references on a work item
optional as not everyone requires this.

Even the internal slow-work stubs them out, so those can be got rid of too.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
This commit is contained in:
Jens Axboe 2009-11-19 18:10:39 +00:00 committed by David Howells
parent 3d7a641e54
commit 4d8bb2cbcc
2 changed files with 17 additions and 21 deletions
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2
Documentation/slow-work.txt
View File

@ -125,7 +125,7 @@ ITEM OPERATIONS
===============
Each work item requires a table of operations of type struct slow_work_ops.
All members are required:
Only ->execute() is required, getting and putting of a reference are optional.
(*) Get a reference on an item:

36
kernel/slow-work.c
View File

@ -145,6 +145,20 @@ static DECLARE_COMPLETION(slow_work_last_thread_exited);
static int slow_work_user_count;
static DEFINE_MUTEX(slow_work_user_lock);
static inline int slow_work_get_ref(struct slow_work *work)
{
if (work->ops->get_ref)
return work->ops->get_ref(work);
return 0;
}
static inline void slow_work_put_ref(struct slow_work *work)
{
if (work->ops->put_ref)
work->ops->put_ref(work);
}
/*
* Calculate the maximum number of active threads in the pool that are
* permitted to process very slow work items.
@ -248,7 +262,7 @@ static bool slow_work_execute(int id)
}
/* sort out the race between module unloading and put_ref() */
work->ops->put_ref(work);
slow_work_put_ref(work);
#ifdef CONFIG_MODULES
module = slow_work_thread_processing[id];
@ -309,7 +323,6 @@ int slow_work_enqueue(struct slow_work *work)
BUG_ON(slow_work_user_count <= 0);
BUG_ON(!work);
BUG_ON(!work->ops);
BUG_ON(!work->ops->get_ref);
/* when honouring an enqueue request, we only promise that we will run
* the work function in the future; we do not promise to run it once
@ -339,7 +352,7 @@ int slow_work_enqueue(struct slow_work *work)
if (test_bit(SLOW_WORK_EXECUTING, &work->flags)) {
set_bit(SLOW_WORK_ENQ_DEFERRED, &work->flags);
} else {
if (work->ops->get_ref(work) < 0)
if (slow_work_get_ref(work) < 0)
goto cant_get_ref;
if (test_bit(SLOW_WORK_VERY_SLOW, &work->flags))
list_add_tail(&work->link, &vslow_work_queue);
@ -479,21 +492,6 @@ static void slow_work_cull_timeout(unsigned long data)
wake_up(&slow_work_thread_wq);
}
/*
* Get a reference on slow work thread starter
*/
static int slow_work_new_thread_get_ref(struct slow_work *work)
{
return 0;
}
/*
* Drop a reference on slow work thread starter
*/
static void slow_work_new_thread_put_ref(struct slow_work *work)
{
}
/*
* Start a new slow work thread
*/
@ -529,8 +527,6 @@ static void slow_work_new_thread_execute(struct slow_work *work)
static const struct slow_work_ops slow_work_new_thread_ops = {
.owner = THIS_MODULE,
.get_ref = slow_work_new_thread_get_ref,
.put_ref = slow_work_new_thread_put_ref,
.execute = slow_work_new_thread_execute,
};