RPC: Clean up RPC task structure

 Shrink the RPC task structure. Instead of storing separate pointers
 for task->tk_exit and task->tk_release, put them in a structure.

 Also pass the user data pointer as a parameter instead of passing it via
 task->tk_calldata. This enables us to nest callbacks.

 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

2 files changed, 36 insertions, 32 deletions

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 6ab4cbd8a901..8b2f75bc006d 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -374,10 +374,14 @@ out:
  * Default callback for async RPC calls
  */
 static void
-rpc_default_callback(struct rpc_task *task)
+rpc_default_callback(struct rpc_task *task, void *data)
 {
 }
 
+static const struct rpc_call_ops rpc_default_ops = {
+        .rpc_call_done = rpc_default_callback,
+};
+
 /*
  *      Export the signal mask handling for synchronous code that
  *      sleeps on RPC calls
@@ -432,7 +436,7 @@ int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
         BUG_ON(flags & RPC_TASK_ASYNC);
 
         status = -ENOMEM;
-        task = rpc_new_task(clnt, NULL, flags);
+        task = rpc_new_task(clnt, flags, &rpc_default_ops, NULL);
         if (task == NULL)
                 goto out;
 
@@ -459,7 +463,7 @@ out:
  */
 int
 rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
-               rpc_action callback, void *data)
+               const struct rpc_call_ops *tk_ops, void *data)
 {
         struct rpc_task *task;
         sigset_t        oldset;
@@ -472,12 +476,9 @@ rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
         flags |= RPC_TASK_ASYNC;
 
         /* Create/initialize a new RPC task */
-        if (!callback)
-                callback = rpc_default_callback;
         status = -ENOMEM;
-        if (!(task = rpc_new_task(clnt, callback, flags)))
+        if (!(task = rpc_new_task(clnt, flags, tk_ops, data)))
                 goto out;
-        task->tk_calldata = data;
 
         /* Mask signals on GSS_AUTH upcalls */
         rpc_task_sigmask(task, &oldset);                
diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index 3fcf7b0e1f6c..8d6233d3248b 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -555,13 +555,13 @@ __rpc_atrun(struct rpc_task *task)
 }
 
 /*
- * Helper that calls task->tk_exit if it exists
+ * Helper that calls task->tk_ops->rpc_call_done if it exists
  */
 void rpc_exit_task(struct rpc_task *task)
 {
         task->tk_action = NULL;
-        if (task->tk_exit != NULL) {
-                task->tk_exit(task);
+        if (task->tk_ops->rpc_call_done != NULL) {
+                task->tk_ops->rpc_call_done(task, task->tk_calldata);
                 if (task->tk_action != NULL) {
                         WARN_ON(RPC_ASSASSINATED(task));
                         /* Always release the RPC slot and buffer memory */
@@ -747,7 +747,7 @@ rpc_free(struct rpc_task *task)
 /*
  * Creation and deletion of RPC task structures
  */
-void rpc_init_task(struct rpc_task *task, struct rpc_clnt *clnt, rpc_action callback, int flags)
+void rpc_init_task(struct rpc_task *task, struct rpc_clnt *clnt, int flags, const struct rpc_call_ops *tk_ops, void *calldata)
 {
         memset(task, 0, sizeof(*task));
         init_timer(&task->tk_timer);
@@ -755,7 +755,8 @@ void rpc_init_task(struct rpc_task *task, struct rpc_clnt *clnt, rpc_action call
         task->tk_timer.function = (void (*)(unsigned long)) rpc_run_timer;
         task->tk_client = clnt;
         task->tk_flags  = flags;
-        task->tk_exit   = callback;
+        task->tk_ops = tk_ops;
+        task->tk_calldata = calldata;
 
         /* Initialize retry counters */
         task->tk_garb_retry = 2;
@@ -784,6 +785,8 @@ void rpc_init_task(struct rpc_task *task, struct rpc_clnt *clnt, rpc_action call
         list_add_tail(&task->tk_task, &all_tasks);
         spin_unlock(&rpc_sched_lock);
 
+        BUG_ON(task->tk_ops == NULL);
+
         dprintk("RPC: %4d new task procpid %d\n", task->tk_pid,
                                 current->pid);
 }
@@ -794,8 +797,7 @@ rpc_alloc_task(void)
         return (struct rpc_task *)mempool_alloc(rpc_task_mempool, GFP_NOFS);
 }
 
-static void
-rpc_default_free_task(struct rpc_task *task)
+static void rpc_free_task(struct rpc_task *task)
 {
         dprintk("RPC: %4d freeing task\n", task->tk_pid);
         mempool_free(task, rpc_task_mempool);
@@ -806,8 +808,7 @@ rpc_default_free_task(struct rpc_task *task)
  * clean up after an allocation failure, as the client may
  * have specified "oneshot".
  */
-struct rpc_task *
-rpc_new_task(struct rpc_clnt *clnt, rpc_action callback, int flags)
+struct rpc_task *rpc_new_task(struct rpc_clnt *clnt, int flags, const struct rpc_call_ops *tk_ops, void *calldata)
 {
         struct rpc_task *task;
 
@@ -815,10 +816,7 @@ rpc_new_task(struct rpc_clnt *clnt, rpc_action callback, int flags)
         if (!task)
                 goto cleanup;
 
-        rpc_init_task(task, clnt, callback, flags);
-
-        /* Replace tk_release */
-        task->tk_release = rpc_default_free_task;
+        rpc_init_task(task, clnt, flags, tk_ops, calldata);
 
         dprintk("RPC: %4d allocated task\n", task->tk_pid);
         task->tk_flags |= RPC_TASK_DYNAMIC;
@@ -838,6 +836,8 @@ cleanup:
 
 void rpc_release_task(struct rpc_task *task)
 {
+        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
@@ -869,8 +869,10 @@ void rpc_release_task(struct rpc_task *task)
 #ifdef RPC_DEBUG
         task->tk_magic = 0;
 #endif
-        if (task->tk_release)
-                task->tk_release(task);
+        if (task->tk_flags & RPC_TASK_DYNAMIC)
+                rpc_free_task(task);
+        if (tk_ops->rpc_release)
+                tk_ops->rpc_release(calldata);
 }
 
 /**
@@ -883,12 +885,11 @@ void rpc_release_task(struct rpc_task *task)
  *
  * Caller must hold childq.lock
  */
-static inline struct rpc_task *rpc_find_parent(struct rpc_task *child)
+static inline struct rpc_task *rpc_find_parent(struct rpc_task *child, struct rpc_task *parent)
 {
-        struct rpc_task *task, *parent;
+        struct rpc_task *task;
         struct list_head *le;
 
-        parent = (struct rpc_task *) child->tk_calldata;
         task_for_each(task, le, &childq.tasks[0])
                 if (task == parent)
                         return parent;
@@ -896,18 +897,22 @@ static inline struct rpc_task *rpc_find_parent(struct rpc_task *child)
         return NULL;
 }
 
-static void rpc_child_exit(struct rpc_task *child)
+static void rpc_child_exit(struct rpc_task *child, void *calldata)
 {
         struct rpc_task *parent;
 
         spin_lock_bh(&childq.lock);
-        if ((parent = rpc_find_parent(child)) != NULL) {
+        if ((parent = rpc_find_parent(child, calldata)) != NULL) {
                 parent->tk_status = child->tk_status;
                 __rpc_wake_up_task(parent);
         }
         spin_unlock_bh(&childq.lock);
 }
 
+static const struct rpc_call_ops rpc_child_ops = {
+        .rpc_call_done = rpc_child_exit,
+};
+
 /*
  * Note: rpc_new_task releases the client after a failure.
  */
@@ -916,11 +921,9 @@ rpc_new_child(struct rpc_clnt *clnt, struct rpc_task *parent)
 {
         struct rpc_task *task;
 
-        task = rpc_new_task(clnt, NULL, RPC_TASK_ASYNC | RPC_TASK_CHILD);
+        task = rpc_new_task(clnt, RPC_TASK_ASYNC | RPC_TASK_CHILD, &rpc_child_ops, parent);
         if (!task)
                 goto fail;
-        task->tk_exit = rpc_child_exit;
-        task->tk_calldata = parent;
         return task;
 
 fail:
@@ -1056,7 +1059,7 @@ void rpc_show_tasks(void)
                 return;
         }
         printk("-pid- proc flgs status -client- -prog- --rqstp- -timeout "
-                "-rpcwait -action- --exit--\n");
+                "-rpcwait -action- ---ops--\n");
         alltask_for_each(t, le, &all_tasks) {
                 const char *rpc_waitq = "none";
 
@@ -1071,7 +1074,7 @@ void rpc_show_tasks(void)
                         (t->tk_client ? t->tk_client->cl_prog : 0),
                         t->tk_rqstp, t->tk_timeout,
                         rpc_waitq,
-                        t->tk_action, t->tk_exit);
+                        t->tk_action, t->tk_ops);
         }
         spin_unlock(&rpc_sched_lock);
 }