linux-kernel - [PATCH v2] PM: domains: Fix return value of API dev_pm_get_subsys

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Message-Id: <20241112-fix_dev_pm_get_subsys_data-v2-1-3774257ede73@quicinc.com>
Date: Tue, 12 Nov 2024 23:21:45 +0800
From: Zijun Hu <zijun_hu@...oud.com>
To: "Rafael J. Wysocki" <rafael@...nel.org>, Pavel Machek <pavel@....cz>, 
 Len Brown <len.brown@...el.com>, 
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Zijun Hu <zijun_hu@...oud.com>, linux-pm@...r.kernel.org, 
 linux-kernel@...r.kernel.org, Zijun Hu <quic_zijuhu@...cinc.com>
Subject: [PATCH v2] PM: domains: Fix return value of API
 dev_pm_get_subsys_data()

From: Zijun Hu <quic_zijuhu@...cinc.com>

dev_pm_get_subsys_data() has below 2 issues under condition
(@dev->power.subsys_data != NULL):

- it will do unnecessary kzalloc() and kfree().
- it will return -ENOMEM if the kzalloc() fails, that is wrong
  it should return 0 since the kzalloc() is not needed.

Fix by not doing kzalloc() and returning 0 for the condition.

Signed-off-by: Zijun Hu <quic_zijuhu@...cinc.com>
---
Changes in v2:
- Remove both stable and fix tag
- Correct commit message
- Link to v1: https://lore.kernel.org/r/20241010-fix_dev_pm_get_subsys_data-v1-1-2250e8f0051b@quicinc.com
---
 drivers/base/power/common.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/base/power/common.c b/drivers/base/power/common.c
index cca2fd0a1aed..a3cec013092c 100644
--- a/drivers/base/power/common.c
+++ b/drivers/base/power/common.c
@@ -26,6 +26,14 @@ int dev_pm_get_subsys_data(struct device *dev)
 {
 	struct pm_subsys_data *psd;

+	spin_lock_irq(&dev->power.lock);
+	if (dev->power.subsys_data) {
+		dev->power.subsys_data->refcount++;
+		spin_unlock_irq(&dev->power.lock);
+		return 0;
+	}
+	spin_unlock_irq(&dev->power.lock);
+
 	psd = kzalloc(sizeof(*psd), GFP_KERNEL);
 	if (!psd)
 		return -ENOMEM;

---
base-commit: 9bd133f05b1dca5ca4399a76d04d0f6f4d454e44
change-id: 20241010-fix_dev_pm_get_subsys_data-2478bb200fde

Best regards,
-- 
Zijun Hu <quic_zijuhu@...cinc.com>