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SUNRPC: Add a new helper rpc_wake_up_queued_task()

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In all cases where we currently use rpc_wake_up_task(), we almost always
know on which waitqueue the rpc_task is actually sleeping. This will allows
us to simplify the queue locking in a future patch.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Trond Myklebust
2008-02-22 15:46:41 -05:00
parent fde95c7554
commit 96ef13b283
3 changed files with 34 additions and 36 deletions
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64
net/sunrpc/sched.c
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@ -148,7 +148,7 @@ static void __rpc_add_wait_queue(struct rpc_wait_queue *queue, struct rpc_task *
list_add(&task->u.tk_wait.list, &queue->tasks[0]);
else
list_add_tail(&task->u.tk_wait.list, &queue->tasks[0]);
task->u.tk_wait.rpc_waitq = queue;
task->tk_waitqueue = queue;
queue->qlen++;
rpc_set_queued(task);
@ -175,11 +175,8 @@ static void __rpc_remove_wait_queue_priority(struct rpc_task *task)
* Remove request from queue.
* Note: must be called with spin lock held.
*/
static void __rpc_remove_wait_queue(struct rpc_task *task)
static void __rpc_remove_wait_queue(struct rpc_wait_queue *queue, struct rpc_task *task)
{
struct rpc_wait_queue *queue;
queue = task->u.tk_wait.rpc_waitq;
if (RPC_IS_PRIORITY(queue))
__rpc_remove_wait_queue_priority(task);
else
@ -364,11 +361,12 @@ EXPORT_SYMBOL_GPL(rpc_sleep_on);
/**
* __rpc_do_wake_up_task - wake up a single rpc_task
* @queue: wait queue
* @task: task to be woken up
*
* Caller must hold queue->lock, and have cleared the task queued flag.
*/
static void __rpc_do_wake_up_task(struct rpc_task *task)
static void __rpc_do_wake_up_task(struct rpc_wait_queue *queue, struct rpc_task *task)
{
dprintk("RPC: %5u __rpc_wake_up_task (now %lu)\n",
task->tk_pid, jiffies);
@ -383,7 +381,7 @@ static void __rpc_do_wake_up_task(struct rpc_task *task)
}
__rpc_disable_timer(task);
__rpc_remove_wait_queue(task);
__rpc_remove_wait_queue(queue, task);
rpc_make_runnable(task);
@ -391,35 +389,37 @@ static void __rpc_do_wake_up_task(struct rpc_task *task)
}
/*
* Wake up the specified task
* Wake up a queued task while the queue lock is being held
*/
static void __rpc_wake_up_task(struct rpc_task *task)
static void rpc_wake_up_task_queue_locked(struct rpc_wait_queue *queue, struct rpc_task *task)
{
if (!RPC_IS_QUEUED(task) || task->tk_waitqueue != queue)
return;
if (rpc_start_wakeup(task)) {
if (RPC_IS_QUEUED(task))
__rpc_do_wake_up_task(task);
__rpc_do_wake_up_task(queue, task);
rpc_finish_wakeup(task);
}
}
/*
* Wake up a task on a specific queue
*/
void rpc_wake_up_queued_task(struct rpc_wait_queue *queue, struct rpc_task *task)
{
rcu_read_lock_bh();
spin_lock(&queue->lock);
rpc_wake_up_task_queue_locked(queue, task);
spin_unlock(&queue->lock);
rcu_read_unlock_bh();
}
EXPORT_SYMBOL_GPL(rpc_wake_up_queued_task);
/*
* Wake up the specified task
*/
void rpc_wake_up_task(struct rpc_task *task)
{
rcu_read_lock_bh();
if (rpc_start_wakeup(task)) {
if (RPC_IS_QUEUED(task)) {
struct rpc_wait_queue *queue = task->u.tk_wait.rpc_waitq;
/* Note: we're already in a bh-safe context */
spin_lock(&queue->lock);
__rpc_do_wake_up_task(task);
spin_unlock(&queue->lock);
}
rpc_finish_wakeup(task);
}
rcu_read_unlock_bh();
rpc_wake_up_queued_task(task->tk_waitqueue, task);
}
EXPORT_SYMBOL_GPL(rpc_wake_up_task);
@ -471,7 +471,7 @@ new_queue:
new_owner:
rpc_set_waitqueue_owner(queue, task->tk_owner);
out:
__rpc_wake_up_task(task);
rpc_wake_up_task_queue_locked(queue, task);
return task;
}
@ -490,7 +490,7 @@ struct rpc_task * rpc_wake_up_next(struct rpc_wait_queue *queue)
task = __rpc_wake_up_next_priority(queue);
else {
task_for_first(task, &queue->tasks[0])
__rpc_wake_up_task(task);
rpc_wake_up_task_queue_locked(queue, task);
}
spin_unlock(&queue->lock);
rcu_read_unlock_bh();
@ -515,7 +515,7 @@ void rpc_wake_up(struct rpc_wait_queue *queue)
head = &queue->tasks[queue->maxpriority];
for (;;) {
list_for_each_entry_safe(task, next, head, u.tk_wait.list)
__rpc_wake_up_task(task);
rpc_wake_up_task_queue_locked(queue, task);
if (head == &queue->tasks[0])
break;
head--;
@ -543,7 +543,7 @@ void rpc_wake_up_status(struct rpc_wait_queue *queue, int status)
for (;;) {
list_for_each_entry_safe(task, next, head, u.tk_wait.list) {
task->tk_status = status;
__rpc_wake_up_task(task);
rpc_wake_up_task_queue_locked(queue, task);
}
if (head == &queue->tasks[0])
break;
@ -562,10 +562,8 @@ static void rpc_run_timer(unsigned long ptr)
struct rpc_task *task = (struct rpc_task *)ptr;
void (*callback)(struct rpc_task *);
if (!rpc_start_wakeup(task))
goto out;
if (RPC_IS_QUEUED(task)) {
struct rpc_wait_queue *queue = task->u.tk_wait.rpc_waitq;
struct rpc_wait_queue *queue = task->tk_waitqueue;
callback = task->tk_timeout_fn;
dprintk("RPC: %5u running timer\n", task->tk_pid);
@ -573,11 +571,9 @@ static void rpc_run_timer(unsigned long ptr)
callback(task);
/* Note: we're already in a bh-safe context */
spin_lock(&queue->lock);
__rpc_do_wake_up_task(task);
rpc_wake_up_task_queue_locked(queue, task);
spin_unlock(&queue->lock);
}
rpc_finish_wakeup(task);
out:
smp_mb__before_clear_bit();
clear_bit(RPC_TASK_HAS_TIMER, &task->tk_runstate);
smp_mb__after_clear_bit();