1 files changed, 111 insertions, 97 deletions

diff --git a/fs/afs/rxrpc.c b/fs/afs/rxrpc.c
index 25f05a8d21b1..95f42872b787 100644
--- a/fs/afs/rxrpc.c
+++ b/fs/afs/rxrpc.c
@@ -19,35 +19,16 @@
 struct socket *afs_socket; /* my RxRPC socket */
 static struct workqueue_struct *afs_async_calls;
 static struct afs_call *afs_spare_incoming_call;
-static atomic_t afs_outstanding_calls;
+atomic_t afs_outstanding_calls;
 
-static void afs_free_call(struct afs_call *);
 static void afs_wake_up_call_waiter(struct sock *, struct rxrpc_call *, unsigned long);
 static int afs_wait_for_call_to_complete(struct afs_call *);
 static void afs_wake_up_async_call(struct sock *, struct rxrpc_call *, unsigned long);
-static int afs_dont_wait_for_call_to_complete(struct afs_call *);
 static void afs_process_async_call(struct work_struct *);
 static void afs_rx_new_call(struct sock *, struct rxrpc_call *, unsigned long);
 static void afs_rx_discard_new_call(struct rxrpc_call *, unsigned long);
 static int afs_deliver_cm_op_id(struct afs_call *);
 
-/* synchronous call management */
-const struct afs_wait_mode afs_sync_call = {
-	.notify_rx	= afs_wake_up_call_waiter,
-	.wait		= afs_wait_for_call_to_complete,
-};
-
-/* asynchronous call management */
-const struct afs_wait_mode afs_async_call = {
-	.notify_rx	= afs_wake_up_async_call,
-	.wait		= afs_dont_wait_for_call_to_complete,
-};
-
-/* asynchronous incoming call management */
-static const struct afs_wait_mode afs_async_incoming_call = {
-	.notify_rx	= afs_wake_up_async_call,
-};
-
 /* asynchronous incoming call initial processing */
 static const struct afs_call_type afs_RXCMxxxx = {
 	.name		= "CB.xxxx",
@@ -130,9 +111,11 @@ void afs_close_socket(void)
 {
 	_enter("");
 
+	kernel_listen(afs_socket, 0);
+	flush_workqueue(afs_async_calls);
+
 	if (afs_spare_incoming_call) {
-		atomic_inc(&afs_outstanding_calls);
-		afs_free_call(afs_spare_incoming_call);
+		afs_put_call(afs_spare_incoming_call);
 		afs_spare_incoming_call = NULL;
 	}
 
@@ -141,7 +124,6 @@ void afs_close_socket(void)
 			 TASK_UNINTERRUPTIBLE);
 	_debug("no outstanding calls");
 
-	flush_workqueue(afs_async_calls);
 	kernel_sock_shutdown(afs_socket, SHUT_RDWR);
 	flush_workqueue(afs_async_calls);
 	sock_release(afs_socket);
@@ -152,44 +134,79 @@ void afs_close_socket(void)
 }
 
 /*
- * free a call
+ * Allocate a call.
  */
-static void afs_free_call(struct afs_call *call)
+static struct afs_call *afs_alloc_call(const struct afs_call_type *type,
+				       gfp_t gfp)
 {
-	_debug("DONE %p{%s} [%d]",
-	       call, call->type->name, atomic_read(&afs_outstanding_calls));
+	struct afs_call *call;
+	int o;
 
-	ASSERTCMP(call->rxcall, ==, NULL);
-	ASSERT(!work_pending(&call->async_work));
-	ASSERT(call->type->name != NULL);
+	call = kzalloc(sizeof(*call), gfp);
+	if (!call)
+		return NULL;
 
-	kfree(call->request);
-	kfree(call);
+	call->type = type;
+	atomic_set(&call->usage, 1);
+	INIT_WORK(&call->async_work, afs_process_async_call);
+	init_waitqueue_head(&call->waitq);
 
-	if (atomic_dec_and_test(&afs_outstanding_calls))
-		wake_up_atomic_t(&afs_outstanding_calls);
+	o = atomic_inc_return(&afs_outstanding_calls);
+	trace_afs_call(call, afs_call_trace_alloc, 1, o,
+		       __builtin_return_address(0));
+	return call;
 }
 
 /*
- * End a call but do not free it
+ * Dispose of a reference on a call.
  */
-static void afs_end_call_nofree(struct afs_call *call)
+void afs_put_call(struct afs_call *call)
 {
-	if (call->rxcall) {
-		rxrpc_kernel_end_call(afs_socket, call->rxcall);
-		call->rxcall = NULL;
+	int n = atomic_dec_return(&call->usage);
+	int o = atomic_read(&afs_outstanding_calls);
+
+	trace_afs_call(call, afs_call_trace_put, n + 1, o,
+		       __builtin_return_address(0));
+
+	ASSERTCMP(n, >=, 0);
+	if (n == 0) {
+		ASSERT(!work_pending(&call->async_work));
+		ASSERT(call->type->name != NULL);
+
+		if (call->rxcall) {
+			rxrpc_kernel_end_call(afs_socket, call->rxcall);
+			call->rxcall = NULL;
+		}
+		if (call->type->destructor)
+			call->type->destructor(call);
+
+		kfree(call->request);
+		kfree(call);
+
+		o = atomic_dec_return(&afs_outstanding_calls);
+		trace_afs_call(call, afs_call_trace_free, 0, o,
+			       __builtin_return_address(0));
+		if (o == 0)
+			wake_up_atomic_t(&afs_outstanding_calls);
 	}
-	if (call->type->destructor)
-		call->type->destructor(call);
 }
 
 /*
- * End a call and free it
+ * Queue the call for actual work.  Returns 0 unconditionally for convenience.
  */
-static void afs_end_call(struct afs_call *call)
+int afs_queue_call_work(struct afs_call *call)
 {
-	afs_end_call_nofree(call);
-	afs_free_call(call);
+	int u = atomic_inc_return(&call->usage);
+
+	trace_afs_call(call, afs_call_trace_work, u,
+		       atomic_read(&afs_outstanding_calls),
+		       __builtin_return_address(0));
+
+	INIT_WORK(&call->work, call->type->work);
+
+	if (!queue_work(afs_wq, &call->work))
+		afs_put_call(call);
+	return 0;
 }
 
 /*
@@ -200,25 +217,19 @@ struct afs_call *afs_alloc_flat_call(const struct afs_call_type *type,
 {
 	struct afs_call *call;
 
-	call = kzalloc(sizeof(*call), GFP_NOFS);
+	call = afs_alloc_call(type, GFP_NOFS);
 	if (!call)
 		goto nomem_call;
 
-	_debug("CALL %p{%s} [%d]",
-	       call, type->name, atomic_read(&afs_outstanding_calls));
-	atomic_inc(&afs_outstanding_calls);
-
-	call->type = type;
-	call->request_size = request_size;
-	call->reply_max = reply_max;
-
 	if (request_size) {
+		call->request_size = request_size;
 		call->request = kmalloc(request_size, GFP_NOFS);
 		if (!call->request)
 			goto nomem_free;
 	}
 
 	if (reply_max) {
+		call->reply_max = reply_max;
 		call->buffer = kmalloc(reply_max, GFP_NOFS);
 		if (!call->buffer)
 			goto nomem_free;
@@ -228,7 +239,7 @@ struct afs_call *afs_alloc_flat_call(const struct afs_call_type *type,
 	return call;
 
 nomem_free:
-	afs_free_call(call);
+	afs_put_call(call);
 nomem_call:
 	return NULL;
 }
@@ -315,7 +326,7 @@ static int afs_send_pages(struct afs_call *call, struct msghdr *msg,
  * initiate a call
  */
 int afs_make_call(struct in_addr *addr, struct afs_call *call, gfp_t gfp,
-		  const struct afs_wait_mode *wait_mode)
+		  bool async)
 {
 	struct sockaddr_rxrpc srx;
 	struct rxrpc_call *rxcall;
@@ -332,8 +343,7 @@ int afs_make_call(struct in_addr *addr, struct afs_call *call, gfp_t gfp,
 	       call, call->type->name, key_serial(call->key),
 	       atomic_read(&afs_outstanding_calls));
 
-	call->wait_mode = wait_mode;
-	INIT_WORK(&call->async_work, afs_process_async_call);
+	call->async = async;
 
 	memset(&srx, 0, sizeof(srx));
 	srx.srx_family = AF_RXRPC;
@@ -347,7 +357,9 @@ int afs_make_call(struct in_addr *addr, struct afs_call *call, gfp_t gfp,
 	/* create a call */
 	rxcall = rxrpc_kernel_begin_call(afs_socket, &srx, call->key,
 					 (unsigned long) call, gfp,
-					 wait_mode->notify_rx);
+					 (async ?
+					  afs_wake_up_async_call :
+					  afs_wake_up_call_waiter));
 	call->key = NULL;
 	if (IS_ERR(rxcall)) {
 		ret = PTR_ERR(rxcall);
@@ -386,12 +398,15 @@ int afs_make_call(struct in_addr *addr, struct afs_call *call, gfp_t gfp,
 
 	/* at this point, an async call may no longer exist as it may have
 	 * already completed */
-	return wait_mode->wait(call);
+	if (call->async)
+		return -EINPROGRESS;
+
+	return afs_wait_for_call_to_complete(call);
 
 error_do_abort:
 	rxrpc_kernel_abort_call(afs_socket, rxcall, RX_USER_ABORT, -ret, "KSD");
 error_kill_call:
-	afs_end_call(call);
+	afs_put_call(call);
 	_leave(" = %d", ret);
 	return ret;
 }
@@ -416,6 +431,8 @@ static void afs_deliver_to_call(struct afs_call *call)
 			ret = rxrpc_kernel_recv_data(afs_socket, call->rxcall,
 						     NULL, 0, &offset, false,
 						     &call->abort_code);
+			trace_afs_recv_data(call, 0, offset, false, ret);
+
 			if (ret == -EINPROGRESS || ret == -EAGAIN)
 				return;
 			if (ret == 1 || ret < 0) {
@@ -459,7 +476,7 @@ static void afs_deliver_to_call(struct afs_call *call)
 
 done:
 	if (call->state == AFS_CALL_COMPLETE && call->incoming)
-		afs_end_call(call);
+		afs_put_call(call);
 out:
 	_leave("");
 	return;
@@ -516,7 +533,7 @@ static int afs_wait_for_call_to_complete(struct afs_call *call)
 	}
 
 	_debug("call complete");
-	afs_end_call(call);
+	afs_put_call(call);
 	_leave(" = %d", ret);
 	return ret;
 }
@@ -540,24 +557,25 @@ static void afs_wake_up_async_call(struct sock *sk, struct rxrpc_call *rxcall,
 				   unsigned long call_user_ID)
 {
 	struct afs_call *call = (struct afs_call *)call_user_ID;
+	int u;
 
+	trace_afs_notify_call(rxcall, call);
 	call->need_attention = true;
-	queue_work(afs_async_calls, &call->async_work);
-}
 
-/*
- * put a call into asynchronous mode
- * - mustn't touch the call descriptor as the call my have completed by the
- *   time we get here
- */
-static int afs_dont_wait_for_call_to_complete(struct afs_call *call)
-{
-	_enter("");
-	return -EINPROGRESS;
+	u = __atomic_add_unless(&call->usage, 1, 0);
+	if (u != 0) {
+		trace_afs_call(call, afs_call_trace_wake, u,
+			       atomic_read(&afs_outstanding_calls),
+			       __builtin_return_address(0));
+
+		if (!queue_work(afs_async_calls, &call->async_work))
+			afs_put_call(call);
+	}
 }
 
 /*
- * delete an asynchronous call
+ * Delete an asynchronous call.  The work item carries a ref to the call struct
+ * that we need to release.
  */
 static void afs_delete_async_call(struct work_struct *work)
 {
@@ -565,13 +583,14 @@ static void afs_delete_async_call(struct work_struct *work)
 
 	_enter("");
 
-	afs_free_call(call);
+	afs_put_call(call);
 
 	_leave("");
 }
 
 /*
- * perform processing on an asynchronous call
+ * Perform I/O processing on an asynchronous call.  The work item carries a ref
+ * to the call struct that we either need to release or to pass on.
  */
 static void afs_process_async_call(struct work_struct *work)
 {
@@ -584,21 +603,19 @@ static void afs_process_async_call(struct work_struct *work)
 		afs_deliver_to_call(call);
 	}
 
-	if (call->state == AFS_CALL_COMPLETE && call->wait_mode) {
-		if (call->wait_mode->async_complete)
-			call->wait_mode->async_complete(call->reply,
-							call->error);
+	if (call->state == AFS_CALL_COMPLETE) {
 		call->reply = NULL;
 
-		/* kill the call */
-		afs_end_call_nofree(call);
-
-		/* we can't just delete the call because the work item may be
-		 * queued */
+		/* We have two refs to release - one from the alloc and one
+		 * queued with the work item - and we can't just deallocate the
+		 * call because the work item may be queued again.
+		 */
 		call->async_work.func = afs_delete_async_call;
-		queue_work(afs_async_calls, &call->async_work);
+		if (!queue_work(afs_async_calls, &call->async_work))
+			afs_put_call(call);
 	}
 
+	afs_put_call(call);
 	_leave("");
 }
 
@@ -618,15 +635,13 @@ static void afs_charge_preallocation(struct work_struct *work)
 
 	for (;;) {
 		if (!call) {
-			call = kzalloc(sizeof(struct afs_call), GFP_KERNEL);
+			call = afs_alloc_call(&afs_RXCMxxxx, GFP_KERNEL);
 			if (!call)
 				break;
 
-			INIT_WORK(&call->async_work, afs_process_async_call);
-			call->wait_mode = &afs_async_incoming_call;
-			call->type = &afs_RXCMxxxx;
-			init_waitqueue_head(&call->waitq);
+			call->async = true;
 			call->state = AFS_CALL_AWAIT_OP_ID;
+			init_waitqueue_head(&call->waitq);
 		}
 
 		if (rxrpc_kernel_charge_accept(afs_socket,
@@ -648,9 +663,8 @@ static void afs_rx_discard_new_call(struct rxrpc_call *rxcall,
 {
 	struct afs_call *call = (struct afs_call *)user_call_ID;
 
-	atomic_inc(&afs_outstanding_calls);
 	call->rxcall = NULL;
-	afs_free_call(call);
+	afs_put_call(call);
 }
 
 /*
@@ -659,7 +673,6 @@ static void afs_rx_discard_new_call(struct rxrpc_call *rxcall,
 static void afs_rx_new_call(struct sock *sk, struct rxrpc_call *rxcall,
 			    unsigned long user_call_ID)
 {
-	atomic_inc(&afs_outstanding_calls);
 	queue_work(afs_wq, &afs_charge_preallocation_work);
 }
 
@@ -689,6 +702,8 @@ static int afs_deliver_cm_op_id(struct afs_call *call)
 	if (!afs_cm_incoming_call(call))
 		return -ENOTSUPP;
 
+	trace_afs_cb_call(call);
+
 	/* pass responsibility for the remainer of this message off to the
 	 * cache manager op */
 	return call->type->deliver(call);
@@ -721,7 +736,6 @@ void afs_send_empty_reply(struct afs_call *call)
 		rxrpc_kernel_abort_call(afs_socket, call->rxcall,
 					RX_USER_ABORT, ENOMEM, "KOO");
 	default:
-		afs_end_call(call);
 		_leave(" [error]");
 		return;
 	}
@@ -760,7 +774,6 @@ void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
 		rxrpc_kernel_abort_call(afs_socket, call->rxcall,
 					RX_USER_ABORT, ENOMEM, "KOO");
 	}
-	afs_end_call(call);
 	_leave(" [error]");
 }
 
@@ -780,6 +793,7 @@ int afs_extract_data(struct afs_call *call, void *buf, size_t count,
 	ret = rxrpc_kernel_recv_data(afs_socket, call->rxcall,
 				     buf, count, &call->offset,
 				     want_more, &call->abort_code);
+	trace_afs_recv_data(call, count, call->offset, want_more, ret);
 	if (ret == 0 || ret == -EAGAIN)
 		return ret;