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[PATCH] Add a semaphore to struct device to synchronize calls to its driver.

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This adds a per-device semaphore that is taken before every call from the core to a
driver method. This prevents e.g. simultaneous calls to the ->suspend() or ->resume()
and ->probe() or ->release(), potentially saving a whole lot of headaches.

It also moves us a step closer to removing the bus rwsem, since it protects the fields
in struct device that are modified by the core.

Signed-off-by: Patrick Mochel <mochel@digitalimplant.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
mochel@digitalimplant.org
2005-03-21 10:41:04 -08:00
committed by Greg Kroah-Hartman
parent eb51b65005
commit af70316af1
5 changed files with 24 additions and 6 deletions
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14
drivers/base/bus.c
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@@ -283,18 +283,22 @@ void device_bind_driver(struct device * dev)
*/
int driver_probe_device(struct device_driver * drv, struct device * dev)
{
int error = 0;
if (drv->bus->match && !drv->bus->match(dev, drv))
return -ENODEV;
down(&dev->sem);
dev->driver = drv;
if (drv->probe) {
int error = drv->probe(dev);
error = drv->probe(dev);
if (error) {
dev->driver = NULL;
up(&dev->sem);
return error;
}
}
up(&dev->sem);
device_bind_driver(dev);
return 0;
}
@@ -385,7 +389,10 @@ void driver_attach(struct device_driver * drv)
void device_release_driver(struct device * dev)
{
struct device_driver * drv = dev->driver;
struct device_driver * drv;
down(&dev->sem);
drv = dev->driver;
if (drv) {
sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj));
sysfs_remove_link(&dev->kobj, "driver");
@@ -394,6 +401,7 @@ void device_release_driver(struct device * dev)
drv->remove(dev);
dev->driver = NULL;
}
up(&dev->sem);
}