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authormochel@digitalimplant.org <mochel@digitalimplant.org>2005-03-21 10:41:04 -0800
committerGreg Kroah-Hartman <gregkh@suse.de>2005-06-20 15:15:12 -0700
commitaf70316af182f4716cc5eec7e0d27fc731d164bd (patch)
tree22fa4732c8270db8fd3f681355cd83e4b8088847 /drivers/base/bus.c
parenteb51b65005737b777e0709683b061d5f82aefd97 (diff)
downloadop-kernel-dev-af70316af182f4716cc5eec7e0d27fc731d164bd.zip
op-kernel-dev-af70316af182f4716cc5eec7e0d27fc731d164bd.tar.gz
[PATCH] Add a semaphore to struct device to synchronize calls to its driver.
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>
Diffstat (limited to 'drivers/base/bus.c')
-rw-r--r--drivers/base/bus.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index 80ce88d..aa27f76 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -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);
}
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