[RFC/RFT][PATCH v2 1/7] driver core: Add a wrapper around __device_release_driver()

From: Rafael J. Wysocki
Date: Thu Sep 08 2016 - 17:26:39 EST


From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

Add an internal wrapper around __device_release_driver() that will
acquire device locks and do the necessary checks before calling it.

A subsequent change will make use of it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
drivers/base/dd.c | 30 ++++++++++++++++++------------
1 file changed, 18 insertions(+), 12 deletions(-)

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 16688f50729c..d9e76e9205c7 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -796,6 +796,22 @@ static void __device_release_driver(struct device *dev)
}
}

+static void device_release_driver_internal(struct device *dev,
+ struct device_driver *drv,
+ struct device *parent)
+{
+ if (parent)
+ device_lock(parent);
+
+ device_lock(dev);
+ if (!drv || drv == dev->driver)
+ __device_release_driver(dev);
+
+ device_unlock(dev);
+ if (parent)
+ device_unlock(parent);
+}
+
/**
* device_release_driver - manually detach device from driver.
* @dev: device.
@@ -810,9 +826,7 @@ void device_release_driver(struct device *dev)
* within their ->remove callback for the same device, they
* will deadlock right here.
*/
- device_lock(dev);
- __device_release_driver(dev);
- device_unlock(dev);
+ device_release_driver_internal(dev, NULL, NULL);
}
EXPORT_SYMBOL_GPL(device_release_driver);

@@ -837,15 +851,7 @@ void driver_detach(struct device_driver *drv)
dev = dev_prv->device;
get_device(dev);
spin_unlock(&drv->p->klist_devices.k_lock);
-
- if (dev->parent) /* Needed for USB */
- device_lock(dev->parent);
- device_lock(dev);
- if (dev->driver == drv)
- __device_release_driver(dev);
- device_unlock(dev);
- if (dev->parent)
- device_unlock(dev->parent);
+ device_release_driver_internal(dev, drv, dev->parent);
put_device(dev);
}
}