linux-kernel - [PATCH 5.9 047/252] PM: runtime: Add pm_runtime_resume_and

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Message-Id: <20201123121837.857006136@linuxfoundation.org>
Date:   Mon, 23 Nov 2020 13:19:57 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Zhang Qilong <zhangqilong3@...wei.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Jakub Kicinski <kuba@...nel.org>
Subject: [PATCH 5.9 047/252] PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter

From: Zhang Qilong <zhangqilong3@...wei.com>

[ Upstream commit dd8088d5a8969dc2b42f71d7bc01c25c61a78066 ]

In many case, we need to check return value of pm_runtime_get_sync, but
it brings a trouble to the usage counter processing. Many callers forget
to decrease the usage counter when it failed, which could resulted in
reference leak. It has been discussed a lot[0][1]. So we add a function
to deal with the usage counter for better coding.

[0]https://lkml.org/lkml/2020/6/14/88
[1]https://patchwork.ozlabs.org/project/linux-tegra/list/?series=178139
Signed-off-by: Zhang Qilong <zhangqilong3@...wei.com>
Acked-by: Rafael J. Wysocki  <rafael.j.wysocki@...el.com>
Signed-off-by: Jakub Kicinski <kuba@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 include/linux/pm_runtime.h |   21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

--- a/include/linux/pm_runtime.h
+++ b/include/linux/pm_runtime.h
@@ -387,6 +387,27 @@ static inline int pm_runtime_get_sync(st
 }
 
 /**
+ * pm_runtime_resume_and_get - Bump up usage counter of a device and resume it.
+ * @dev: Target device.
+ *
+ * Resume @dev synchronously and if that is successful, increment its runtime
+ * PM usage counter. Return 0 if the runtime PM usage counter of @dev has been
+ * incremented or a negative error code otherwise.
+ */
+static inline int pm_runtime_resume_and_get(struct device *dev)
+{
+	int ret;
+
+	ret = __pm_runtime_resume(dev, RPM_GET_PUT);
+	if (ret < 0) {
+		pm_runtime_put_noidle(dev);
+		return ret;
+	}
+
+	return 0;
+}
+
+/**
  * pm_runtime_put - Drop device usage counter and queue up "idle check" if 0.
  * @dev: Target device.
  *