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Commit c12766ec authored by Rafael J. Wysocki's avatar Rafael J. Wysocki Committed by Greg Kroah-Hartman
Browse files

ACPI: scan: Rearrange memory allocation in acpi_device_add() 



[ Upstream commit c1013ff7a5472db637c56bb6237f8343398c03a7 ]

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: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: default avatarHans de Goede <hdegoede@redhat.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 74bc0e51

drivers/acpi/scan.c

+26 −31
Original line number Diff line number Diff line
@@ -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 = acpi_device_bus_id_match(acpi_device_hid(device));

	if (acpi_device_bus_id) {

		acpi_device_bus_id->instance_no++;

			found = 1;

			kfree(new_bus_id);

			break;

		}

	} 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;

}