From: Jianxin Pan <jianxin.pan@amlogic.com>
Date: Wed, 26 Jun 2019 09:08:49 +0000 (-0400)
Subject: cpu_hotplug: fix dead lock between flush work and ipa [1/1]
X-Git-Tag: hardkernel-4.9.236-104~1001
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=ce6d55237804849968125e199ce6672874819612;p=platform%2Fkernel%2Flinux-amlogic.git

cpu_hotplug: fix dead lock between flush work and ipa [1/1]

PD#TV-7161

Problem:
dead lock between flush work and ipa

Solution:
fix dead lock between flush work and ipa

Verify:
TL1

Change-Id: I479869601c0816bbaeaa693a26bf606b6a168da0
Signed-off-by: Jianxin Pan <jianxin.pan@amlogic.com>
---

diff --git a/drivers/amlogic/cpu_hotplug/cpu_hotplug.c b/drivers/amlogic/cpu_hotplug/cpu_hotplug.c
index 8010e88..3df6617 100644
--- a/drivers/amlogic/cpu_hotplug/cpu_hotplug.c
+++ b/drivers/amlogic/cpu_hotplug/cpu_hotplug.c
@@ -33,6 +33,7 @@
 #include <linux/sched/rt.h>
 #include <linux/notifier.h>
 #include "linux/amlogic/cpu_hotplug.h"
+#include <linux/delay.h>
 
 #define MAX_CLUSTRS		2
 struct cpu_hotplug_s {
@@ -102,7 +103,8 @@ void cpu_hotplug_set_max(unsigned int num, int clustr)
 		return;
 	}
 
-	mutex_lock(&hpg.mutex);
+	if (!mutex_trylock(&hpg.mutex))
+		return;
 	if (num > hpg.cpunum[clustr])
 		num = hpg.cpunum[clustr];
 	if (hpg.max_num[clustr] == num) {
@@ -157,7 +159,10 @@ static int __ref cpu_hotplug_thread(void *data)
 	while (1) {
 		if (kthread_should_stop())
 			break;
-		mutex_lock(&hpg.mutex);
+		if (!mutex_trylock(&hpg.mutex)) {
+			usleep_range(1000, 2000);
+			continue;
+		}
 		for (clustr = 0; clustr < hpg.clusters; clustr++) {
 			if (!hpg.flgs[clustr])
 				continue;