From: Zhang Qilong <zhangqilong3@huawei.com>
To: <rjw@rjwysocki.net>, <fugang.duan@nxp.com>, <davem@davemloft.net>,
<kuba@kernel.org>
Cc: <linux-pm@vger.kernel.org>, <netdev@vger.kernel.org>
Subject: [PATCH v2 1/2] PM: runtime: Add a general runtime get sync operation to deal with usage counter
Date: Mon, 9 Nov 2020 23:04:15 +0800 [thread overview]
Message-ID: <20201109150416.1877878-2-zhangqilong3@huawei.com> (raw)
In-Reply-To: <20201109150416.1877878-1-zhangqilong3@huawei.com>
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. 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/patch/20200520095148.10995-1-dinghao.liu@zju.edu.cn/
Signed-off-by: Zhang Qilong <zhangqilong3@huawei.com>
---
include/linux/pm_runtime.h | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)
diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h
index 4b708f4e8eed..6549ce764400 100644
--- a/include/linux/pm_runtime.h
+++ b/include/linux/pm_runtime.h
@@ -386,6 +386,36 @@ static inline int pm_runtime_get_sync(struct device *dev)
return __pm_runtime_resume(dev, RPM_GET_PUT);
}
+/**
+ * pm_runtime_general_get - Bump up usage counter of a device and resume it.
+ * @dev: Target device.
+ *
+ * Increase runtime PM usage counter of @dev first, and carry out runtime-resume
+ * of it synchronously. If __pm_runtime_resume return negative value(device is in
+ * error state), we to need decrease the usage counter before it return. If
+ * __pm_runtime_resume return positive value, it means the runtime of device has
+ * already been in active state, and we let the new wrapper return zero instead.
+ *
+ * The possible return values of this function is zero or negative value.
+ * zero:
+ * - it means resume succeeed or runtime of device has already been active, the
+ * runtime PM usage counter of @dev remains incremented.
+ * negative:
+ * - it means failure and the runtime PM usage counter of @dev has been balanced.
+ */
+static inline int pm_runtime_general_get(struct device *dev)
+{
+ int ret = 0;
+
+ 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.
--
2.25.4
next prev parent reply other threads:[~2020-11-09 15:00 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-09 15:04 [PATCH v2 0/2] Fix usage counter leak by adding a general sync ops Zhang Qilong
2020-11-09 15:04 ` Zhang Qilong [this message]
2020-11-09 15:20 ` [PATCH v2 1/2] PM: runtime: Add a general runtime get sync operation to deal with usage counter Rafael J. Wysocki
2020-11-09 15:49 ` Ulf Hansson
2020-11-09 15:53 ` Rafael J. Wysocki
2020-11-09 16:05 ` Ulf Hansson
2020-11-09 15:50 ` 答复: " zhangqilong
2020-11-09 16:00 ` Rafael J. Wysocki
2020-11-09 16:15 ` 答复: " zhangqilong
2020-11-09 16:40 ` Rafael J. Wysocki
2020-11-09 15:04 ` [PATCH v2 2/2] net: fec: Fix reference count leak in fec series ops Zhang Qilong
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