1 files changed, 171 insertions, 87 deletions

diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index ce5eb68a9664..f4385e45a5fc 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -62,6 +62,7 @@
 /*
  * Local functions
  */
+static void	 xprt_init(struct rpc_xprt *xprt, struct net *net);
 static void	xprt_request_init(struct rpc_task *, struct rpc_xprt *);
 static void	xprt_connect_status(struct rpc_task *task);
 static int      __xprt_get_cong(struct rpc_xprt *, struct rpc_task *);
@@ -186,15 +187,16 @@ EXPORT_SYMBOL_GPL(xprt_load_transport);
 /**
  * xprt_reserve_xprt - serialize write access to transports
  * @task: task that is requesting access to the transport
+ * @xprt: pointer to the target transport
  *
  * This prevents mixing the payload of separate requests, and prevents
  * transport connects from colliding with writes.  No congestion control
  * is provided.
  */
-int xprt_reserve_xprt(struct rpc_task *task)
+int xprt_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
 {
 	struct rpc_rqst *req = task->tk_rqstp;
-	struct rpc_xprt	*xprt = req->rq_xprt;
+	int priority;
 
 	if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {
 		if (task == xprt->snd_task)
@@ -202,8 +204,10 @@ int xprt_reserve_xprt(struct rpc_task *task)
 		goto out_sleep;
 	}
 	xprt->snd_task = task;
-	req->rq_bytes_sent = 0;
-	req->rq_ntrans++;
+	if (req != NULL) {
+		req->rq_bytes_sent = 0;
+		req->rq_ntrans++;
+	}
 
 	return 1;
 
@@ -212,10 +216,13 @@ out_sleep:
 			task->tk_pid, xprt);
 	task->tk_timeout = 0;
 	task->tk_status = -EAGAIN;
-	if (req->rq_ntrans)
-		rpc_sleep_on(&xprt->resend, task, NULL);
+	if (req == NULL)
+		priority = RPC_PRIORITY_LOW;
+	else if (!req->rq_ntrans)
+		priority = RPC_PRIORITY_NORMAL;
 	else
-		rpc_sleep_on(&xprt->sending, task, NULL);
+		priority = RPC_PRIORITY_HIGH;
+	rpc_sleep_on_priority(&xprt->sending, task, NULL, priority);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(xprt_reserve_xprt);
@@ -239,22 +246,24 @@ static void xprt_clear_locked(struct rpc_xprt *xprt)
  * integrated into the decision of whether a request is allowed to be
  * woken up and given access to the transport.
  */
-int xprt_reserve_xprt_cong(struct rpc_task *task)
+int xprt_reserve_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task)
 {
-	struct rpc_xprt	*xprt = task->tk_xprt;
 	struct rpc_rqst *req = task->tk_rqstp;
+	int priority;
 
 	if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {
 		if (task == xprt->snd_task)
 			return 1;
 		goto out_sleep;
 	}
+	if (req == NULL) {
+		xprt->snd_task = task;
+		return 1;
+	}
 	if (__xprt_get_cong(xprt, task)) {
 		xprt->snd_task = task;
-		if (req) {
-			req->rq_bytes_sent = 0;
-			req->rq_ntrans++;
-		}
+		req->rq_bytes_sent = 0;
+		req->rq_ntrans++;
 		return 1;
 	}
 	xprt_clear_locked(xprt);
@@ -262,10 +271,13 @@ out_sleep:
 	dprintk("RPC: %5u failed to lock transport %p\n", task->tk_pid, xprt);
 	task->tk_timeout = 0;
 	task->tk_status = -EAGAIN;
-	if (req && req->rq_ntrans)
-		rpc_sleep_on(&xprt->resend, task, NULL);
+	if (req == NULL)
+		priority = RPC_PRIORITY_LOW;
+	else if (!req->rq_ntrans)
+		priority = RPC_PRIORITY_NORMAL;
 	else
-		rpc_sleep_on(&xprt->sending, task, NULL);
+		priority = RPC_PRIORITY_HIGH;
+	rpc_sleep_on_priority(&xprt->sending, task, NULL, priority);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(xprt_reserve_xprt_cong);
@@ -275,7 +287,7 @@ static inline int xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task)
 	int retval;
 
 	spin_lock_bh(&xprt->transport_lock);
-	retval = xprt->ops->reserve_xprt(task);
+	retval = xprt->ops->reserve_xprt(xprt, task);
 	spin_unlock_bh(&xprt->transport_lock);
 	return retval;
 }
@@ -288,12 +300,9 @@ static void __xprt_lock_write_next(struct rpc_xprt *xprt)
 	if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
 		return;
 
-	task = rpc_wake_up_next(&xprt->resend);
-	if (!task) {
-		task = rpc_wake_up_next(&xprt->sending);
-		if (!task)
-			goto out_unlock;
-	}
+	task = rpc_wake_up_next(&xprt->sending);
+	if (task == NULL)
+		goto out_unlock;
 
 	req = task->tk_rqstp;
 	xprt->snd_task = task;
@@ -310,24 +319,25 @@ out_unlock:
 static void __xprt_lock_write_next_cong(struct rpc_xprt *xprt)
 {
 	struct rpc_task *task;
+	struct rpc_rqst *req;
 
 	if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
 		return;
 	if (RPCXPRT_CONGESTED(xprt))
 		goto out_unlock;
-	task = rpc_wake_up_next(&xprt->resend);
-	if (!task) {
-		task = rpc_wake_up_next(&xprt->sending);
-		if (!task)
-			goto out_unlock;
+	task = rpc_wake_up_next(&xprt->sending);
+	if (task == NULL)
+		goto out_unlock;
+
+	req = task->tk_rqstp;
+	if (req == NULL) {
+		xprt->snd_task = task;
+		return;
 	}
 	if (__xprt_get_cong(xprt, task)) {
-		struct rpc_rqst *req = task->tk_rqstp;
 		xprt->snd_task = task;
-		if (req) {
-			req->rq_bytes_sent = 0;
-			req->rq_ntrans++;
-		}
+		req->rq_bytes_sent = 0;
+		req->rq_ntrans++;
 		return;
 	}
 out_unlock:
@@ -852,7 +862,7 @@ int xprt_prepare_transmit(struct rpc_task *task)
 		err = req->rq_reply_bytes_recvd;
 		goto out_unlock;
 	}
-	if (!xprt->ops->reserve_xprt(task))
+	if (!xprt->ops->reserve_xprt(xprt, task))
 		err = -EAGAIN;
 out_unlock:
 	spin_unlock_bh(&xprt->transport_lock);
@@ -928,28 +938,66 @@ void xprt_transmit(struct rpc_task *task)
 	spin_unlock_bh(&xprt->transport_lock);
 }
 
+static struct rpc_rqst *xprt_dynamic_alloc_slot(struct rpc_xprt *xprt, gfp_t gfp_flags)
+{
+	struct rpc_rqst *req = ERR_PTR(-EAGAIN);
+
+	if (!atomic_add_unless(&xprt->num_reqs, 1, xprt->max_reqs))
+		goto out;
+	req = kzalloc(sizeof(struct rpc_rqst), gfp_flags);
+	if (req != NULL)
+		goto out;
+	atomic_dec(&xprt->num_reqs);
+	req = ERR_PTR(-ENOMEM);
+out:
+	return req;
+}
+
+static bool xprt_dynamic_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *req)
+{
+	if (atomic_add_unless(&xprt->num_reqs, -1, xprt->min_reqs)) {
+		kfree(req);
+		return true;
+	}
+	return false;
+}
+
 static void xprt_alloc_slot(struct rpc_task *task)
 {
 	struct rpc_xprt	*xprt = task->tk_xprt;
+	struct rpc_rqst *req;
 
-	task->tk_status = 0;
-	if (task->tk_rqstp)
-		return;
 	if (!list_empty(&xprt->free)) {
-		struct rpc_rqst	*req = list_entry(xprt->free.next, struct rpc_rqst, rq_list);
-		list_del_init(&req->rq_list);
-		task->tk_rqstp = req;
-		xprt_request_init(task, xprt);
-		return;
+		req = list_entry(xprt->free.next, struct rpc_rqst, rq_list);
+		list_del(&req->rq_list);
+		goto out_init_req;
+	}
+	req = xprt_dynamic_alloc_slot(xprt, GFP_NOWAIT);
+	if (!IS_ERR(req))
+		goto out_init_req;
+	switch (PTR_ERR(req)) {
+	case -ENOMEM:
+		rpc_delay(task, HZ >> 2);
+		dprintk("RPC:       dynamic allocation of request slot "
+				"failed! Retrying\n");
+		break;
+	case -EAGAIN:
+		rpc_sleep_on(&xprt->backlog, task, NULL);
+		dprintk("RPC:       waiting for request slot\n");
 	}
-	dprintk("RPC:       waiting for request slot\n");
 	task->tk_status = -EAGAIN;
-	task->tk_timeout = 0;
-	rpc_sleep_on(&xprt->backlog, task, NULL);
+	return;
+out_init_req:
+	task->tk_status = 0;
+	task->tk_rqstp = req;
+	xprt_request_init(task, xprt);
 }
 
 static void xprt_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *req)
 {
+	if (xprt_dynamic_free_slot(xprt, req))
+		return;
+
 	memset(req, 0, sizeof(*req));	/* mark unused */
 
 	spin_lock(&xprt->reserve_lock);
@@ -958,25 +1006,49 @@ static void xprt_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *req)
 	spin_unlock(&xprt->reserve_lock);
 }
 
-struct rpc_xprt *xprt_alloc(struct net *net, int size, int max_req)
+static void xprt_free_all_slots(struct rpc_xprt *xprt)
+{
+	struct rpc_rqst *req;
+	while (!list_empty(&xprt->free)) {
+		req = list_first_entry(&xprt->free, struct rpc_rqst, rq_list);
+		list_del(&req->rq_list);
+		kfree(req);
+	}
+}
+
+struct rpc_xprt *xprt_alloc(struct net *net, size_t size,
+		unsigned int num_prealloc,
+		unsigned int max_alloc)
 {
 	struct rpc_xprt *xprt;
+	struct rpc_rqst *req;
+	int i;
 
 	xprt = kzalloc(size, GFP_KERNEL);
 	if (xprt == NULL)
 		goto out;
-	atomic_set(&xprt->count, 1);
 
-	xprt->max_reqs = max_req;
-	xprt->slot = kcalloc(max_req, sizeof(struct rpc_rqst), GFP_KERNEL);
-	if (xprt->slot == NULL)
+	xprt_init(xprt, net);
+
+	for (i = 0; i < num_prealloc; i++) {
+		req = kzalloc(sizeof(struct rpc_rqst), GFP_KERNEL);
+		if (!req)
+			break;
+		list_add(&req->rq_list, &xprt->free);
+	}
+	if (i < num_prealloc)
 		goto out_free;
+	if (max_alloc > num_prealloc)
+		xprt->max_reqs = max_alloc;
+	else
+		xprt->max_reqs = num_prealloc;
+	xprt->min_reqs = num_prealloc;
+	atomic_set(&xprt->num_reqs, num_prealloc);
 
-	xprt->xprt_net = get_net(net);
 	return xprt;
 
 out_free:
-	kfree(xprt);
+	xprt_free(xprt);
 out:
 	return NULL;
 }
@@ -985,7 +1057,7 @@ EXPORT_SYMBOL_GPL(xprt_alloc);
 void xprt_free(struct rpc_xprt *xprt)
 {
 	put_net(xprt->xprt_net);
-	kfree(xprt->slot);
+	xprt_free_all_slots(xprt);
 	kfree(xprt);
 }
 EXPORT_SYMBOL_GPL(xprt_free);
@@ -1001,10 +1073,24 @@ void xprt_reserve(struct rpc_task *task)
 {
 	struct rpc_xprt	*xprt = task->tk_xprt;
 
-	task->tk_status = -EIO;
+	task->tk_status = 0;
+	if (task->tk_rqstp != NULL)
+		return;
+
+	/* Note: grabbing the xprt_lock_write() here is not strictly needed,
+	 * but ensures that we throttle new slot allocation if the transport
+	 * is congested (e.g. if reconnecting or if we're out of socket
+	 * write buffer space).
+	 */
+	task->tk_timeout = 0;
+	task->tk_status = -EAGAIN;
+	if (!xprt_lock_write(xprt, task))
+		return;
+
 	spin_lock(&xprt->reserve_lock);
 	xprt_alloc_slot(task);
 	spin_unlock(&xprt->reserve_lock);
+	xprt_release_write(xprt, task);
 }
 
 static inline __be32 xprt_alloc_xid(struct rpc_xprt *xprt)
@@ -1021,6 +1107,7 @@ static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt)
 {
 	struct rpc_rqst	*req = task->tk_rqstp;
 
+	INIT_LIST_HEAD(&req->rq_list);
 	req->rq_timeout = task->tk_client->cl_timeout->to_initval;
 	req->rq_task	= task;
 	req->rq_xprt    = xprt;
@@ -1073,6 +1160,34 @@ void xprt_release(struct rpc_task *task)
 		xprt_free_bc_request(req);
 }
 
+static void xprt_init(struct rpc_xprt *xprt, struct net *net)
+{
+	atomic_set(&xprt->count, 1);
+
+	spin_lock_init(&xprt->transport_lock);
+	spin_lock_init(&xprt->reserve_lock);
+
+	INIT_LIST_HEAD(&xprt->free);
+	INIT_LIST_HEAD(&xprt->recv);
+#if defined(CONFIG_SUNRPC_BACKCHANNEL)
+	spin_lock_init(&xprt->bc_pa_lock);
+	INIT_LIST_HEAD(&xprt->bc_pa_list);
+#endif /* CONFIG_SUNRPC_BACKCHANNEL */
+
+	xprt->last_used = jiffies;
+	xprt->cwnd = RPC_INITCWND;
+	xprt->bind_index = 0;
+
+	rpc_init_wait_queue(&xprt->binding, "xprt_binding");
+	rpc_init_wait_queue(&xprt->pending, "xprt_pending");
+	rpc_init_priority_wait_queue(&xprt->sending, "xprt_sending");
+	rpc_init_priority_wait_queue(&xprt->backlog, "xprt_backlog");
+
+	xprt_init_xid(xprt);
+
+	xprt->xprt_net = get_net(net);
+}
+
 /**
  * xprt_create_transport - create an RPC transport
  * @args: rpc transport creation arguments
@@ -1081,7 +1196,6 @@ void xprt_release(struct rpc_task *task)
 struct rpc_xprt *xprt_create_transport(struct xprt_create *args)
 {
 	struct rpc_xprt	*xprt;
-	struct rpc_rqst	*req;
 	struct xprt_class *t;
 
 	spin_lock(&xprt_list_lock);
@@ -1100,46 +1214,17 @@ found:
 	if (IS_ERR(xprt)) {
 		dprintk("RPC:       xprt_create_transport: failed, %ld\n",
 				-PTR_ERR(xprt));
-		return xprt;
+		goto out;
 	}
-	if (test_and_set_bit(XPRT_INITIALIZED, &xprt->state))
-		/* ->setup returned a pre-initialized xprt: */
-		return xprt;
-
-	spin_lock_init(&xprt->transport_lock);
-	spin_lock_init(&xprt->reserve_lock);
-
-	INIT_LIST_HEAD(&xprt->free);
-	INIT_LIST_HEAD(&xprt->recv);
-#if defined(CONFIG_NFS_V4_1)
-	spin_lock_init(&xprt->bc_pa_lock);
-	INIT_LIST_HEAD(&xprt->bc_pa_list);
-#endif /* CONFIG_NFS_V4_1 */
-
 	INIT_WORK(&xprt->task_cleanup, xprt_autoclose);
 	if (xprt_has_timer(xprt))
 		setup_timer(&xprt->timer, xprt_init_autodisconnect,
 			    (unsigned long)xprt);
 	else
 		init_timer(&xprt->timer);
-	xprt->last_used = jiffies;
-	xprt->cwnd = RPC_INITCWND;
-	xprt->bind_index = 0;
-
-	rpc_init_wait_queue(&xprt->binding, "xprt_binding");
-	rpc_init_wait_queue(&xprt->pending, "xprt_pending");
-	rpc_init_wait_queue(&xprt->sending, "xprt_sending");
-	rpc_init_wait_queue(&xprt->resend, "xprt_resend");
-	rpc_init_priority_wait_queue(&xprt->backlog, "xprt_backlog");
-
-	/* initialize free list */
-	for (req = &xprt->slot[xprt->max_reqs-1]; req >= &xprt->slot[0]; req--)
-		list_add(&req->rq_list, &xprt->free);
-
-	xprt_init_xid(xprt);
-
 	dprintk("RPC:       created transport %p with %u slots\n", xprt,
 			xprt->max_reqs);
+out:
 	return xprt;
 }
 
@@ -1157,7 +1242,6 @@ static void xprt_destroy(struct rpc_xprt *xprt)
 	rpc_destroy_wait_queue(&xprt->binding);
 	rpc_destroy_wait_queue(&xprt->pending);
 	rpc_destroy_wait_queue(&xprt->sending);
-	rpc_destroy_wait_queue(&xprt->resend);
 	rpc_destroy_wait_queue(&xprt->backlog);
 	cancel_work_sync(&xprt->task_cleanup);
 	/*