From 423c4f1994bebd8b106251e64ac1fcc04ba2df17 Mon Sep 17 00:00:00 2001
From: shisiyuan <shisiyuan@xiaomi.com>
Date: Tue, 18 May 2021 11:47:43 +0800
Subject: [PATCH] KillZramBackingDevice: Return immediately if backing_dev is
 none.

It's possible that CONFIG_ZRAM_WRITEBACK is y,
but userspace doesn't set the /sys/block/zram0/backing_dev,
so its value is 'none'.
It's the same with "CONFIG_ZRAM_WRITEBACK is not set".

Change-Id: I2df89ceee68e4685deef5113bada21be96779e9b
Signed-off-by: shisiyuan <shisiyuan@xiaomi.com>
---
 init/reboot.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/init/reboot.cpp b/init/reboot.cpp
index ab0e48e9e..0e788e495 100644
--- a/init/reboot.cpp
+++ b/init/reboot.cpp
@@ -478,6 +478,11 @@ static Result<void> KillZramBackingDevice() {
     // cut the last "\n"
     backing_dev.erase(backing_dev.length() - 1);
 
+    if (android::base::StartsWith(backing_dev, "none")) {
+        LOG(INFO) << "No zram backing device configured";
+        return {};
+    }
+
     // shutdown zram handle
     Timer swap_timer;
     LOG(INFO) << "swapoff() start...";