linux-kernel - [PATCH 1/2] ARM: cpuidle: refine failure handling in init flow

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Date:   Mon,  4 Sep 2017 14:52:13 +0800
From:   Leo Yan <leo.yan@...aro.org>
To:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Leo Yan <leo.yan@...aro.org>,
        Stefan Wahren <stefan.wahren@...e.com>
Subject: [PATCH 1/2] ARM: cpuidle: refine failure handling in init flow

After applied Stefan Wahren patch ("ARM: cpuidle: Avoid memleak if init
fail") there have no memleak issue, but the code is not consistent to
handle initialization failure between driver registration and device
registration. And when device registration fails, it misses to
unregister the driver.

So this patch is to refine failure handling in init flow, it adds two
'goto' tags: when register device fails, it goto 'init_dev_fail' tag and
free 'dev' structure and unregister driver; when register driver fails,
it goto 'init_drv_fail' tag and free 'drv' structure.

Cc: Daniel Lezcano <daniel.lezcano@...aro.org>
Cc: Stefan Wahren <stefan.wahren@...e.com>
Signed-off-by: Leo Yan <leo.yan@...aro.org>
---
 drivers/cpuidle/cpuidle-arm.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/drivers/cpuidle/cpuidle-arm.c b/drivers/cpuidle/cpuidle-arm.c
index 52a7505..f419f6a 100644
--- a/drivers/cpuidle/cpuidle-arm.c
+++ b/drivers/cpuidle/cpuidle-arm.c
@@ -86,10 +86,13 @@ static int __init arm_idle_init(void)
 
 	for_each_possible_cpu(cpu) {
 
+		drv = NULL;
+		dev = NULL;
+
 		drv = kmemdup(&arm_idle_driver, sizeof(*drv), GFP_KERNEL);
 		if (!drv) {
 			ret = -ENOMEM;
-			goto out_fail;
+			goto init_drv_fail;
 		}
 
 		drv->cpumask = (struct cpumask *)cpumask_of(cpu);
@@ -104,13 +107,13 @@ static int __init arm_idle_init(void)
 		ret = dt_init_idle_driver(drv, arm_idle_state_match, 1);
 		if (ret <= 0) {
 			ret = ret ? : -ENODEV;
-			goto init_fail;
+			goto init_drv_fail;
 		}
 
 		ret = cpuidle_register_driver(drv);
 		if (ret) {
 			pr_err("Failed to register cpuidle driver\n");
-			goto init_fail;
+			goto init_drv_fail;
 		}
 
 		/*
@@ -128,14 +131,14 @@ static int __init arm_idle_init(void)
 
 		if (ret) {
 			pr_err("CPU %d failed to init idle CPU ops\n", cpu);
-			goto out_fail;
+			goto init_dev_fail;
 		}
 
 		dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 		if (!dev) {
 			pr_err("Failed to allocate cpuidle device\n");
 			ret = -ENOMEM;
-			goto out_fail;
+			goto init_dev_fail;
 		}
 		dev->cpu = cpu;
 
@@ -143,15 +146,19 @@ static int __init arm_idle_init(void)
 		if (ret) {
 			pr_err("Failed to register cpuidle device for CPU %d\n",
 			       cpu);
-			kfree(dev);
-			goto out_fail;
+			goto init_dev_fail;
 		}
 	}
 
 	return 0;
-init_fail:
+
+init_dev_fail:
+	kfree(dev);
+	cpuidle_unregister_driver(drv);
+
+init_drv_fail:
 	kfree(drv);
-out_fail:
+
 	while (--cpu >= 0) {
 		dev = per_cpu(cpuidle_devices, cpu);
 		cpuidle_unregister_device(dev);
-- 
2.7.4