NFSv4: stateful NFSv4 RPC call interface
The NFSv4 model requires us to complete all RPC calls that might
establish state on the server whether or not the user wants to
interrupt it. We may also need to schedule new work (including
new RPC calls) in order to cancel the new state.
The asynchronous RPC model will allow us to ensure that RPC calls
always complete, but in order to allow for "synchronous" RPC, we
want to add the ability to wait for completion.
The waits are, of course, interruptible.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index 2d74a16..82d158d 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -264,6 +264,35 @@
}
EXPORT_SYMBOL(rpc_init_wait_queue);
+static int rpc_wait_bit_interruptible(void *word)
+{
+ if (signal_pending(current))
+ return -ERESTARTSYS;
+ schedule();
+ return 0;
+}
+
+/*
+ * Mark an RPC call as having completed by clearing the 'active' bit
+ */
+static inline void rpc_mark_complete_task(struct rpc_task *task)
+{
+ rpc_clear_active(task);
+ wake_up_bit(&task->tk_runstate, RPC_TASK_ACTIVE);
+}
+
+/*
+ * Allow callers to wait for completion of an RPC call
+ */
+int __rpc_wait_for_completion_task(struct rpc_task *task, int (*action)(void *))
+{
+ if (action == NULL)
+ action = rpc_wait_bit_interruptible;
+ return wait_on_bit(&task->tk_runstate, RPC_TASK_ACTIVE,
+ action, TASK_INTERRUPTIBLE);
+}
+EXPORT_SYMBOL(__rpc_wait_for_completion_task);
+
/*
* Make an RPC task runnable.
*
@@ -299,10 +328,7 @@
static inline void
rpc_schedule_run(struct rpc_task *task)
{
- /* Don't run a child twice! */
- if (RPC_IS_ACTIVATED(task))
- return;
- task->tk_active = 1;
+ rpc_set_active(task);
rpc_make_runnable(task);
}
@@ -324,8 +350,7 @@
}
/* Mark the task as being activated if so needed */
- if (!RPC_IS_ACTIVATED(task))
- task->tk_active = 1;
+ rpc_set_active(task);
__rpc_add_wait_queue(q, task);
@@ -580,14 +605,6 @@
}
EXPORT_SYMBOL(rpc_exit_task);
-static int rpc_wait_bit_interruptible(void *word)
-{
- if (signal_pending(current))
- return -ERESTARTSYS;
- schedule();
- return 0;
-}
-
/*
* This is the RPC `scheduler' (or rather, the finite state machine).
*/
@@ -680,6 +697,8 @@
dprintk("RPC: %4d exit() = %d\n", task->tk_pid, task->tk_status);
status = task->tk_status;
+ /* Wake up anyone who is waiting for task completion */
+ rpc_mark_complete_task(task);
/* Release all resources associated with the task */
rpc_release_task(task);
return status;
@@ -697,9 +716,7 @@
int
rpc_execute(struct rpc_task *task)
{
- BUG_ON(task->tk_active);
-
- task->tk_active = 1;
+ rpc_set_active(task);
rpc_set_running(task);
return __rpc_execute(task);
}
@@ -761,6 +778,7 @@
init_timer(&task->tk_timer);
task->tk_timer.data = (unsigned long) task;
task->tk_timer.function = (void (*)(unsigned long)) rpc_run_timer;
+ atomic_set(&task->tk_count, 1);
task->tk_client = clnt;
task->tk_flags = flags;
task->tk_ops = tk_ops;
@@ -848,11 +866,13 @@
{
const struct rpc_call_ops *tk_ops = task->tk_ops;
void *calldata = task->tk_calldata;
- dprintk("RPC: %4d release task\n", task->tk_pid);
#ifdef RPC_DEBUG
BUG_ON(task->tk_magic != RPC_TASK_MAGIC_ID);
#endif
+ if (!atomic_dec_and_test(&task->tk_count))
+ return;
+ dprintk("RPC: %4d release task\n", task->tk_pid);
/* Remove from global task list */
spin_lock(&rpc_sched_lock);
@@ -860,7 +880,6 @@
spin_unlock(&rpc_sched_lock);
BUG_ON (RPC_IS_QUEUED(task));
- task->tk_active = 0;
/* Synchronously delete any running timer */
rpc_delete_timer(task);
@@ -886,6 +905,27 @@
}
/**
+ * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
+ * @clnt - pointer to RPC client
+ * @flags - RPC flags
+ * @ops - RPC call ops
+ * @data - user call data
+ */
+struct rpc_task *rpc_run_task(struct rpc_clnt *clnt, int flags,
+ const struct rpc_call_ops *ops,
+ void *data)
+{
+ struct rpc_task *task;
+ task = rpc_new_task(clnt, flags, ops, data);
+ if (task == NULL)
+ return ERR_PTR(-ENOMEM);
+ atomic_inc(&task->tk_count);
+ rpc_execute(task);
+ return task;
+}
+EXPORT_SYMBOL(rpc_run_task);
+
+/**
* rpc_find_parent - find the parent of a child task.
* @child: child task
*