diff options
| author | Patrick Mochel <mochel@osdl.org> | 2002-10-08 03:23:05 -0700 |
|---|---|---|
| committer | Patrick Mochel <mochel@osdl.org> | 2002-10-08 03:23:05 -0700 |
| commit | c7a01052c40f9e8fdd61bd90e810a358834a8344 (patch) | |
| tree | 83fcf038748eb585fd738f7ed9ff23ef67172a28 /include/linux | |
| parent | 0bf36f291063c1bec51a12cbf4b072ec5f0aacd1 (diff) | |
driver model: and present field to struct device and implement device_unregister().
device_unregister() is intended to be the complement of device_register(), and assumes
most of the functionality of the current put_device(). It should be called by the bus
driver when a device is physically removed from the system.
It should _not_ be called from a driver's remove() method, as that remove() method is called
via device_detach() in device_unregister().
dev->present is used to flag the physical presence of the device. It is set when the device
is registered, and cleared when unregistered. get_device() checks this flag, and returns
a NULL pointer if cleared. This prevents anyone from obtaining a reference to a device
that has been unregistered (removed), but not yet been freed (e.g. if someone else is
holding a reference to it).
put_device() BUG()s if dev->present is set. A device should be unregistered before it is
freed. This will catch people doing it in the wrong order.
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/device.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/device.h b/include/linux/device.h index ef76b15fa930..dea22c61049c 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -289,6 +289,7 @@ struct device { void *platform_data; /* Platform specific data (e.g. ACPI, BIOS data relevant to device) */ + u32 present; u32 current_state; /* Current operating state. In ACPI-speak, this is D0-D3, D0 being fully functional, and D3 @@ -327,7 +328,7 @@ dev_set_drvdata (struct device *dev, void *data) * High level routines for use by the bus drivers */ extern int device_register(struct device * dev); - +extern void device_unregister(struct device * dev); /* driverfs interface for exporting device attributes */ |