devres: device resource management

Implement device resource management, in short, devres.  A device
driver can allocate arbirary size of devres data which is associated
with a release function.  On driver detach, release function is
invoked on the devres data, then, devres data is freed.

devreses are typed by associated release functions.  Some devreses are
better represented by single instance of the type while others need
multiple instances sharing the same release function.  Both usages are
supported.

devreses can be grouped using devres group such that a device driver
can easily release acquired resources halfway through initialization
or selectively release resources (e.g. resources for port 1 out of 4
ports).

This patch adds devres core including documentation and the following
managed interfaces.

* alloc/free	: devm_kzalloc(), devm_kzfree()
* IO region	: devm_request_region(), devm_release_region()
* IRQ		: devm_request_irq(), devm_free_irq()
* DMA		: dmam_alloc_coherent(), dmam_free_coherent(),
		  dmam_declare_coherent_memory(), dmam_pool_create(),
		  dmam_pool_destroy()
* PCI		: pcim_enable_device(), pcim_pin_device(), pci_is_managed()
* iomap		: devm_ioport_map(), devm_ioport_unmap(), devm_ioremap(),
		  devm_ioremap_nocache(), devm_iounmap(), pcim_iomap_table(),
		  pcim_iomap(), pcim_iounmap()

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index b5bf243..6a48824 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -112,6 +112,7 @@ static int really_probe(void *void_data)
 	atomic_inc(&probe_count);
 	pr_debug("%s: Probing driver %s with device %s\n",
 		 drv->bus->name, drv->name, dev->bus_id);
+	WARN_ON(!list_empty(&dev->devres_head));
 
 	dev->driver = drv;
 	if (driver_sysfs_add(dev)) {
@@ -137,6 +138,7 @@ static int really_probe(void *void_data)
 	goto done;
 
 probe_failed:
+	devres_release_all(dev);
 	driver_sysfs_remove(dev);
 	dev->driver = NULL;
 
@@ -327,6 +329,7 @@ static void __device_release_driver(struct device * dev)
 			dev->bus->remove(dev);
 		else if (drv->remove)
 			drv->remove(dev);
+		devres_release_all(dev);
 		dev->driver = NULL;
 		put_driver(drv);
 	}