From b2117d5f34d30a0e494b6e6d5a680b1c1befeecc Mon Sep 17 00:00:00 2001
From: Arun Kumar Neelakantam <aneela@codeaurora.org>
Date: Fri, 2 Nov 2018 20:04:19 +0530
Subject: [PATCH] net: qrtr: Move rx worker to separate worker thread

In system heavy load cases the rx work queued in global worker queue is
getting delayed and causing clients request timeouts.

Create and use separate worker thread to process qrtr rx packets.

Change-Id: I56793a463820340666288bae6111e160d3fc85b9
Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
---
 net/qrtr/qrtr.c | 30 +++++++++++++++++++++++-------
 1 file changed, 23 insertions(+), 7 deletions(-)

diff --git a/net/qrtr/qrtr.c b/net/qrtr/qrtr.c
index 4005e60893ac..44bba1f6deb0 100644
--- a/net/qrtr/qrtr.c
+++ b/net/qrtr/qrtr.c
@@ -3,6 +3,7 @@
  * Copyright (c) 2015, Sony Mobile Communications Inc.
  * Copyright (c) 2013, 2018-2019 The Linux Foundation. All rights reserved.
  */
+#include <linux/kthread.h>
 #include <linux/module.h>
 #include <linux/netlink.h>
 #include <linux/qrtr.h>
@@ -134,8 +135,10 @@ static DEFINE_MUTEX(qrtr_port_lock);
  * @resume_tx: waiters for a resume tx from the remote
  * @qrtr_tx_lock: lock for qrtr_tx_flow
  * @rx_queue: receive queue
- * @work: scheduled work struct for recv work
  * @item: list item for broadcast list
+ * @kworker: worker thread for recv work
+ * @task: task to run the worker thread
+ * @read_data: scheduled work for recv work
  */
 struct qrtr_node {
 	struct mutex ep_lock;
@@ -150,8 +153,11 @@ struct qrtr_node {
 	struct mutex qrtr_tx_lock; /* for qrtr_tx_flow */
 
 	struct sk_buff_head rx_queue;
-	struct work_struct work;
 	struct list_head item;
+
+	struct kthread_worker kworker;
+	struct task_struct *task;
+	struct kthread_work read_data;
 };
 
 struct qrtr_tx_flow_waiter {
@@ -251,7 +257,9 @@ static void __qrtr_node_release(struct kref *kref)
 	}
 	mutex_unlock(&node->qrtr_tx_lock);
 
-	cancel_work_sync(&node->work);
+	kthread_flush_worker(&node->kworker);
+	kthread_stop(node->task);
+
 	skb_queue_purge(&node->rx_queue);
 	kfree(node);
 }
@@ -675,7 +683,7 @@ int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len)
 	 */
 	if (cb->type != QRTR_TYPE_DATA || cb->dst_node != qrtr_local_nid) {
 		skb_queue_tail(&node->rx_queue, skb);
-		schedule_work(&node->work);
+		kthread_queue_work(&node->kworker, &node->read_data);
 	} else {
 		ipc = qrtr_port_lookup(cb->dst_port);
 		if (!ipc)
@@ -795,9 +803,10 @@ static void qrtr_fwd_pkt(struct sk_buff *skb, struct qrtr_cb *cb)
 }
 
 /* Handle not atomic operations for a received packet. */
-static void qrtr_node_rx_work(struct work_struct *work)
+static void qrtr_node_rx_work(struct kthread_work *work)
 {
-	struct qrtr_node *node = container_of(work, struct qrtr_node, work);
+	struct qrtr_node *node = container_of(work, struct qrtr_node,
+					      read_data);
 	struct sk_buff *skb;
 
 	while ((skb = skb_dequeue(&node->rx_queue)) != NULL) {
@@ -849,7 +858,6 @@ int qrtr_endpoint_register(struct qrtr_endpoint *ep, unsigned int net_id)
 	if (!node)
 		return -ENOMEM;
 
-	INIT_WORK(&node->work, qrtr_node_rx_work);
 	kref_init(&node->ref);
 	mutex_init(&node->ep_lock);
 	skb_queue_head_init(&node->rx_queue);
@@ -857,6 +865,14 @@ int qrtr_endpoint_register(struct qrtr_endpoint *ep, unsigned int net_id)
 	node->ep = ep;
 	atomic_set(&node->hello_sent, 0);
 
+	kthread_init_work(&node->read_data, qrtr_node_rx_work);
+	kthread_init_worker(&node->kworker);
+	node->task = kthread_run(kthread_worker_fn, &node->kworker, "qrtr_rx");
+	if (IS_ERR(node->task)) {
+		kfree(node);
+		return -ENOMEM;
+	}
+
 	mutex_init(&node->qrtr_tx_lock);
 	INIT_RADIX_TREE(&node->qrtr_tx_flow, GFP_KERNEL);
 	init_waitqueue_head(&node->resume_tx);