SUNRPC: Remove now-redundant RCU-safe rpc_task free path

Now that we've tightened up the locking rules for RPC queue wakeups, we can
remove the RCU-safe kfree calls...

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

fs/nfs/read.c

@@ -58,19 +58,13 @@ struct nfs_read_data *nfs_readdata_alloc(unsigned int pagecount)
 	return p;
 }
 
-static void nfs_readdata_rcu_free(struct rcu_head *head)
+static void nfs_readdata_free(struct nfs_read_data *p)
 {
-	struct nfs_read_data *p = container_of(head, struct nfs_read_data, task.u.tk_rcu);
 	if (p && (p->pagevec != &p->page_array[0]))
 		kfree(p->pagevec);
 	mempool_free(p, nfs_rdata_mempool);
 }
 
-static void nfs_readdata_free(struct nfs_read_data *rdata)
-{
-	call_rcu_bh(&rdata->task.u.tk_rcu, nfs_readdata_rcu_free);
-}
-
 void nfs_readdata_release(void *data)
 {
 	struct nfs_read_data *rdata = data;

fs/nfs/write.c

@@ -58,19 +58,13 @@ struct nfs_write_data *nfs_commit_alloc(void)
 	return p;
 }
 
-static void nfs_commit_rcu_free(struct rcu_head *head)
+void nfs_commit_free(struct nfs_write_data *p)
 {
-	struct nfs_write_data *p = container_of(head, struct nfs_write_data, task.u.tk_rcu);
 	if (p && (p->pagevec != &p->page_array[0]))
 		kfree(p->pagevec);
 	mempool_free(p, nfs_commit_mempool);
 }
 
-void nfs_commit_free(struct nfs_write_data *wdata)
-{
-	call_rcu_bh(&wdata->task.u.tk_rcu, nfs_commit_rcu_free);
-}
-
 struct nfs_write_data *nfs_writedata_alloc(unsigned int pagecount)
 {
 	struct nfs_write_data *p = mempool_alloc(nfs_wdata_mempool, GFP_NOFS);
@@ -92,19 +86,13 @@ struct nfs_write_data *nfs_writedata_alloc(unsigned int pagecount)
 	return p;
 }
 
-static void nfs_writedata_rcu_free(struct rcu_head *head)
+static void nfs_writedata_free(struct nfs_write_data *p)
 {
-	struct nfs_write_data *p = container_of(head, struct nfs_write_data, task.u.tk_rcu);
 	if (p && (p->pagevec != &p->page_array[0]))
 		kfree(p->pagevec);
 	mempool_free(p, nfs_wdata_mempool);
 }
 
-static void nfs_writedata_free(struct nfs_write_data *wdata)
-{
-	call_rcu_bh(&wdata->task.u.tk_rcu, nfs_writedata_rcu_free);
-}
-
 void nfs_writedata_release(void *data)
 {
 	struct nfs_write_data *wdata = data;

include/linux/sunrpc/sched.h

@@ -11,7 +11,6 @@
 
 #include <linux/timer.h>
 #include <linux/sunrpc/types.h>
-#include <linux/rcupdate.h>
 #include <linux/spinlock.h>
 #include <linux/wait.h>
 #include <linux/workqueue.h>
@@ -77,7 +76,6 @@ struct rpc_task {
 	union {
 		struct work_struct	tk_work;	/* Async task work queue */
 		struct rpc_wait		tk_wait;	/* RPC wait */
-		struct rcu_head		tk_rcu;		/* for task deletion */
 	} u;
 
 	unsigned short		tk_timeouts;	/* maj timeouts */

net/sunrpc/sched.c

@@ -393,11 +393,9 @@ static void rpc_wake_up_task_queue_locked(struct rpc_wait_queue *queue, struct r
  */
 void rpc_wake_up_queued_task(struct rpc_wait_queue *queue, struct rpc_task *task)
 {
-	rcu_read_lock_bh();
-	spin_lock(&queue->lock);
+	spin_lock_bh(&queue->lock);
 	rpc_wake_up_task_queue_locked(queue, task);
-	spin_unlock(&queue->lock);
-	rcu_read_unlock_bh();
+	spin_unlock_bh(&queue->lock);
 }
 EXPORT_SYMBOL_GPL(rpc_wake_up_queued_task);
 
@@ -470,16 +468,14 @@ struct rpc_task * rpc_wake_up_next(struct rpc_wait_queue *queue)
 
 	dprintk("RPC:       wake_up_next(%p \"%s\")\n",
 			queue, rpc_qname(queue));
-	rcu_read_lock_bh();
-	spin_lock(&queue->lock);
+	spin_lock_bh(&queue->lock);
 	if (RPC_IS_PRIORITY(queue))
 		task = __rpc_wake_up_next_priority(queue);
 	else {
 		task_for_first(task, &queue->tasks[0])
 			rpc_wake_up_task_queue_locked(queue, task);
 	}
-	spin_unlock(&queue->lock);
-	rcu_read_unlock_bh();
+	spin_unlock_bh(&queue->lock);
 
 	return task;
 }
@@ -496,8 +492,7 @@ void rpc_wake_up(struct rpc_wait_queue *queue)
 	struct rpc_task *task, *next;
 	struct list_head *head;
 
-	rcu_read_lock_bh();
-	spin_lock(&queue->lock);
+	spin_lock_bh(&queue->lock);
 	head = &queue->tasks[queue->maxpriority];
 	for (;;) {
 		list_for_each_entry_safe(task, next, head, u.tk_wait.list)
@@ -506,8 +501,7 @@ void rpc_wake_up(struct rpc_wait_queue *queue)
 			break;
 		head--;
 	}
-	spin_unlock(&queue->lock);
-	rcu_read_unlock_bh();
+	spin_unlock_bh(&queue->lock);
 }
 EXPORT_SYMBOL_GPL(rpc_wake_up);
 
@@ -523,8 +517,7 @@ void rpc_wake_up_status(struct rpc_wait_queue *queue, int status)
 	struct rpc_task *task, *next;
 	struct list_head *head;
 
-	rcu_read_lock_bh();
-	spin_lock(&queue->lock);
+	spin_lock_bh(&queue->lock);
 	head = &queue->tasks[queue->maxpriority];
 	for (;;) {
 		list_for_each_entry_safe(task, next, head, u.tk_wait.list) {
@@ -535,8 +528,7 @@ void rpc_wake_up_status(struct rpc_wait_queue *queue, int status)
 			break;
 		head--;
 	}
-	spin_unlock(&queue->lock);
-	rcu_read_unlock_bh();
+	spin_unlock_bh(&queue->lock);
 }
 EXPORT_SYMBOL_GPL(rpc_wake_up_status);
 
@@ -848,13 +840,6 @@ rpc_alloc_task(void)
 	return (struct rpc_task *)mempool_alloc(rpc_task_mempool, GFP_NOFS);
 }
 
-static void rpc_free_task_rcu(struct rcu_head *rcu)
-{
-	struct rpc_task *task = container_of(rcu, struct rpc_task, u.tk_rcu);
-	dprintk("RPC: %5u freeing task\n", task->tk_pid);
-	mempool_free(task, rpc_task_mempool);
-}
-
 /*
  * Create a new task for the specified client.
  */
@@ -883,8 +868,10 @@ static void rpc_free_task(struct rpc_task *task)
 	const struct rpc_call_ops *tk_ops = task->tk_ops;
 	void *calldata = task->tk_calldata;
 
-	if (task->tk_flags & RPC_TASK_DYNAMIC)
-		call_rcu_bh(&task->u.tk_rcu, rpc_free_task_rcu);
+	if (task->tk_flags & RPC_TASK_DYNAMIC) {
+		dprintk("RPC: %5u freeing task\n", task->tk_pid);
+		mempool_free(task, rpc_task_mempool);
+	}
 	rpc_release_calldata(tk_ops, calldata);
 }