firewire: Switch cdev code over to use register_chrdev and keep a list of devices.
The old mechanism kept a struct cdev for each fw device, but fops->release
would reference this struct after the device got freed in some cases.
Signed-off-by: Kristian Høgsberg <krh@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
diff --git a/drivers/firewire/fw-device.c b/drivers/firewire/fw-device.c
index ccc05e5..b24090a 100644
--- a/drivers/firewire/fw-device.c
+++ b/drivers/firewire/fw-device.c
@@ -25,6 +25,7 @@
#include <linux/kthread.h>
#include <linux/device.h>
#include <linux/delay.h>
+#include <linux/idr.h>
#include "fw-transaction.h"
#include "fw-topology.h"
#include "fw-device.h"
@@ -407,14 +408,31 @@
return 0;
}
+static DEFINE_IDR(fw_device_idr);
+int fw_cdev_major;
+
+struct fw_device *fw_device_from_devt(dev_t devt)
+{
+ struct fw_device *device;
+
+ down_read(&fw_bus_type.subsys.rwsem);
+ device = idr_find(&fw_device_idr, MINOR(devt));
+ up_read(&fw_bus_type.subsys.rwsem);
+
+ return device;
+}
+
static void fw_device_shutdown(struct work_struct *work)
{
struct fw_device *device =
container_of(work, struct fw_device, work.work);
+ int minor = MINOR(device->device.devt);
+
+ down_write(&fw_bus_type.subsys.rwsem);
+ idr_remove(&fw_device_idr, minor);
+ up_write(&fw_bus_type.subsys.rwsem);
device_remove_file(&device->device, &config_rom_attribute);
- cdev_del(&device->cdev);
- unregister_chrdev_region(device->device.devt, 1);
device_for_each_child(&device->device, NULL, shutdown_unit);
device_unregister(&device->device);
}
@@ -434,9 +452,9 @@
static void fw_device_init(struct work_struct *work)
{
- static atomic_t serial = ATOMIC_INIT(-1);
struct fw_device *device =
container_of(work, struct fw_device, work.work);
+ int minor, err;
/* All failure paths here set node->data to NULL, so that we
* don't try to do device_for_each_child() on a kfree()'d
@@ -456,28 +474,24 @@
return;
}
+ err = -ENOMEM;
+ down_write(&fw_bus_type.subsys.rwsem);
+ if (idr_pre_get(&fw_device_idr, GFP_KERNEL))
+ err = idr_get_new(&fw_device_idr, device, &minor);
+ up_write(&fw_bus_type.subsys.rwsem);
+ if (err < 0)
+ goto error;
+
device->device.bus = &fw_bus_type;
device->device.release = fw_device_release;
device->device.parent = device->card->device;
+ device->device.devt = MKDEV(fw_cdev_major, minor);
snprintf(device->device.bus_id, sizeof device->device.bus_id,
- "fw%d", atomic_inc_return(&serial));
-
- if (alloc_chrdev_region(&device->device.devt, 0, 1, "fw")) {
- fw_error("Failed to register char device region.\n");
- goto error;
- }
-
- cdev_init(&device->cdev, &fw_device_ops);
- device->cdev.owner = THIS_MODULE;
- kobject_set_name(&device->cdev.kobj, device->device.bus_id);
- if (cdev_add(&device->cdev, device->device.devt, 1)) {
- fw_error("Failed to register char device.\n");
- goto error;
- }
+ "fw%d", minor);
if (device_add(&device->device)) {
fw_error("Failed to add device.\n");
- goto error;
+ goto error_with_cdev;
}
if (device_create_file(&device->device, &config_rom_attribute) < 0) {
@@ -513,9 +527,11 @@
error_with_device:
device_del(&device->device);
+ error_with_cdev:
+ down_write(&fw_bus_type.subsys.rwsem);
+ idr_remove(&fw_device_idr, minor);
+ up_write(&fw_bus_type.subsys.rwsem);
error:
- cdev_del(&device->cdev);
- unregister_chrdev_region(device->device.devt, 1);
put_device(&device->device);
}