SUNRPC: Add a new helper rpc_wake_up_queued_task()
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>
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 8c6a7f1..fe95bd0 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -1535,7 +1535,7 @@
proc = -1;
if (RPC_IS_QUEUED(t))
- rpc_waitq = rpc_qname(t->u.tk_wait.rpc_waitq);
+ rpc_waitq = rpc_qname(t->tk_waitqueue);
printk("%5u %04d %04x %6d %8p %6d %8p %8ld %8s %8p %8p\n",
t->tk_pid, proc,
diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index 9433a11..9233ace 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -148,7 +148,7 @@
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 @@
* 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 @@
/**
* __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 @@
}
__rpc_disable_timer(task);
- __rpc_remove_wait_queue(task);
+ __rpc_remove_wait_queue(queue, task);
rpc_make_runnable(task);
@@ -391,35 +389,37 @@
}
/*
- * 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_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 @@
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 @@
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 @@
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 @@
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 @@
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();