[S390] tape: cleanup reference counting
Rename tape_get_device to tape_find_device and tape_get_device_reference
to tape_get_device. The old names didn't make too much sense.
Follow the get_device()/put_device() semantic and convert tape_put_device
to a void function.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/char/tape_core.c b/drivers/s390/char/tape_core.c
index 6311018..a7b7e72 100644
--- a/drivers/s390/char/tape_core.c
+++ b/drivers/s390/char/tape_core.c
@@ -511,11 +511,12 @@
* increment the reference count.
*/
struct tape_device *
-tape_get_device_reference(struct tape_device *device)
+tape_get_device(struct tape_device *device)
{
- DBF_EVENT(4, "tape_get_device_reference(%p) = %i\n", device,
- atomic_inc_return(&device->ref_count));
+ int count;
+ count = atomic_inc_return(&device->ref_count);
+ DBF_EVENT(4, "tape_get_device(%p) = %i\n", device, count);
return device;
}
@@ -525,32 +526,25 @@
* The function returns a NULL pointer to be used by the caller
* for clearing reference pointers.
*/
-struct tape_device *
+void
tape_put_device(struct tape_device *device)
{
- int remain;
+ int count;
- remain = atomic_dec_return(&device->ref_count);
- if (remain > 0) {
- DBF_EVENT(4, "tape_put_device(%p) -> %i\n", device, remain);
- } else {
- if (remain < 0) {
- DBF_EVENT(4, "put device without reference\n");
- } else {
- DBF_EVENT(4, "tape_free_device(%p)\n", device);
- kfree(device->modeset_byte);
- kfree(device);
- }
+ count = atomic_dec_return(&device->ref_count);
+ DBF_EVENT(4, "tape_put_device(%p) -> %i\n", device, count);
+ BUG_ON(count < 0);
+ if (count == 0) {
+ kfree(device->modeset_byte);
+ kfree(device);
}
-
- return NULL;
}
/*
* Find tape device by a device index.
*/
struct tape_device *
-tape_get_device(int devindex)
+tape_find_device(int devindex)
{
struct tape_device *device, *tmp;
@@ -558,7 +552,7 @@
read_lock(&tape_device_lock);
list_for_each_entry(tmp, &tape_device_list, node) {
if (tmp->first_minor / TAPE_MINORS_PER_DEV == devindex) {
- device = tape_get_device_reference(tmp);
+ device = tape_get_device(tmp);
break;
}
}
@@ -607,7 +601,8 @@
list_del(&request->list);
/* Decrease ref_count for removed request. */
- request->device = tape_put_device(device);
+ request->device = NULL;
+ tape_put_device(device);
request->rc = -EIO;
if (request->callback != NULL)
request->callback(request, request->callback_data);
@@ -665,9 +660,11 @@
tape_cleanup_device(device);
}
- if (dev_get_drvdata(&cdev->dev)) {
+ device = dev_get_drvdata(&cdev->dev);
+ if (device) {
sysfs_remove_group(&cdev->dev.kobj, &tape_attr_group);
- dev_set_drvdata(&cdev->dev, tape_put_device(dev_get_drvdata(&cdev->dev)));
+ dev_set_drvdata(&cdev->dev, NULL);
+ tape_put_device(device);
}
}
@@ -722,9 +719,8 @@
{
DBF_LH(6, "Free request %p\n", request);
- if (request->device != NULL) {
- request->device = tape_put_device(request->device);
- }
+ if (request->device)
+ tape_put_device(request->device);
kfree(request->cpdata);
kfree(request->cpaddr);
kfree(request);
@@ -839,7 +835,8 @@
BUG_ON(request->status != TAPE_REQUEST_LONG_BUSY);
DBF_LH(6, "%08x: Long busy timeout.\n", device->cdev_id);
__tape_start_next_request(device);
- device->lb_timeout.data = (unsigned long) tape_put_device(device);
+ device->lb_timeout.data = 0UL;
+ tape_put_device(device);
spin_unlock_irq(get_ccwdev_lock(device->cdev));
}
@@ -919,7 +916,7 @@
}
/* Increase use count of device for the added request. */
- request->device = tape_get_device_reference(device);
+ request->device = tape_get_device(device);
if (list_empty(&device->req_queue)) {
/* No other requests are on the queue. Start this one. */
@@ -1118,8 +1115,8 @@
if (req->status == TAPE_REQUEST_LONG_BUSY) {
DBF_EVENT(3, "(%08x): del timer\n", device->cdev_id);
if (del_timer(&device->lb_timeout)) {
- device->lb_timeout.data = (unsigned long)
- tape_put_device(device);
+ device->lb_timeout.data = 0UL;
+ tape_put_device(device);
__tape_start_next_request(device);
}
return;
@@ -1174,7 +1171,7 @@
break;
case TAPE_IO_LONG_BUSY:
device->lb_timeout.data =
- (unsigned long)tape_get_device_reference(device);
+ (unsigned long) tape_get_device(device);
device->lb_timeout.expires = jiffies +
LONG_BUSY_TIMEOUT * HZ;
DBF_EVENT(3, "(%08x): add timer\n", device->cdev_id);
@@ -1327,7 +1324,7 @@
EXPORT_SYMBOL(tape_generic_offline);
EXPORT_SYMBOL(tape_generic_pm_suspend);
EXPORT_SYMBOL(tape_put_device);
-EXPORT_SYMBOL(tape_get_device_reference);
+EXPORT_SYMBOL(tape_get_device);
EXPORT_SYMBOL(tape_state_verbose);
EXPORT_SYMBOL(tape_op_verbose);
EXPORT_SYMBOL(tape_state_set);