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ACPI: scan: Rearrange memory allocation in acpi_device_add() 

The upfront allocation of new_bus_id is done to avoid allocating
memory under acpi_device_lock, but it doesn't really help,
because (1) it leads to many unnecessary memory allocations for
_ADR devices, (2) kstrdup_const() is run under that lock anyway and
(3) it complicates the code.

Rearrange acpi_device_add() to allocate memory for a new struct
acpi_device_bus_id instance only when necessary, eliminate a redundant
local variable from it and reduce the number of labels in there.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
This commit is contained in:
Rafael J. Wysocki 2021-01-14 19:46:47 +01:00
parent 6ee1d745b7
commit c1013ff7a5
1 changed files with 26 additions and 31 deletions
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57
drivers/acpi/scan.c
View File

@ -623,12 +623,23 @@ void acpi_bus_put_acpi_device(struct acpi_device *adev)
put_device(&adev->dev);
}
static struct acpi_device_bus_id *acpi_device_bus_id_match(const char *dev_id)
{
struct acpi_device_bus_id *acpi_device_bus_id;
/* Find suitable bus_id and instance number in acpi_bus_id_list. */
list_for_each_entry(acpi_device_bus_id, &acpi_bus_id_list, node) {
if (!strcmp(acpi_device_bus_id->bus_id, dev_id))
return acpi_device_bus_id;
}
return NULL;
}
int acpi_device_add(struct acpi_device *device,
void (*release)(struct device *))
{
struct acpi_device_bus_id *acpi_device_bus_id;
int result;
struct acpi_device_bus_id *acpi_device_bus_id, *new_bus_id;
int found = 0;
if (device->handle) {
acpi_status status;
@ -654,38 +665,26 @@ int acpi_device_add(struct acpi_device *device,
INIT_LIST_HEAD(&device->del_list);
mutex_init(&device->physical_node_lock);
new_bus_id = kzalloc(sizeof(struct acpi_device_bus_id), GFP_KERNEL);
if (!new_bus_id) {
pr_err(PREFIX "Memory allocation error\n");
result = -ENOMEM;
goto err_detach;
}
mutex_lock(&acpi_device_lock);
/*
* Find suitable bus_id and instance number in acpi_bus_id_list
* If failed, create one and link it into acpi_bus_id_list
*/
list_for_each_entry(acpi_device_bus_id, &acpi_bus_id_list, node) {
if (!strcmp(acpi_device_bus_id->bus_id,
acpi_device_hid(device))) {
acpi_device_bus_id->instance_no++;
found = 1;
kfree(new_bus_id);
break;
acpi_device_bus_id = acpi_device_bus_id_match(acpi_device_hid(device));
if (acpi_device_bus_id) {
acpi_device_bus_id->instance_no++;
} else {
acpi_device_bus_id = kzalloc(sizeof(*acpi_device_bus_id),
GFP_KERNEL);
if (!acpi_device_bus_id) {
result = -ENOMEM;
goto err_unlock;
}
}
if (!found) {
acpi_device_bus_id = new_bus_id;
acpi_device_bus_id->bus_id =
kstrdup_const(acpi_device_hid(device), GFP_KERNEL);
if (!acpi_device_bus_id->bus_id) {
pr_err(PREFIX "Memory allocation error for bus id\n");
kfree(acpi_device_bus_id);
result = -ENOMEM;
goto err_free_new_bus_id;
goto err_unlock;
}
acpi_device_bus_id->instance_no = 0;
list_add_tail(&acpi_device_bus_id->node, &acpi_bus_id_list);
}
dev_set_name(&device->dev, "%s:%02x", acpi_device_bus_id->bus_id, acpi_device_bus_id->instance_no);
@ -720,13 +719,9 @@ int acpi_device_add(struct acpi_device *device,
list_del(&device->node);
list_del(&device->wakeup_list);
err_free_new_bus_id:
if (!found)
kfree(new_bus_id);
err_unlock:
mutex_unlock(&acpi_device_lock);
err_detach:
acpi_detach_data(device->handle, acpi_scan_drop_device);
return result;
}