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Commit 7385e438 authored by Andy Shevchenko's avatar Andy Shevchenko Committed by Greg Kroah-Hartman
Browse files

ACPI: scan: Use unique number for instance_no 



[ Upstream commit eb50aaf960e3bedfef79063411ffd670da94b84b ]

The decrementation of acpi_device_bus_id->instance_no
in acpi_device_del() is incorrect, because it may cause
a duplicate instance number to be allocated next time
a device with the same acpi_device_bus_id is added.

Replace above mentioned approach by using IDA framework.

While at it, define the instance range to be [0, 4096).

Fixes: e49bd2dd ("ACPI: use PNPID:instance_no as bus_id of ACPI device")
Fixes: ca9dc8d4 ("ACPI / scan: Fix acpi_bus_id_list bookkeeping")
Signed-off-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: 4.10+ <stable@vger.kernel.org> # 4.10+
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent c12766ec

drivers/acpi/internal.h

+5 −1
Original line number Diff line number Diff line
@@ -18,6 +18,8 @@ 
#ifndef _ACPI_INTERNAL_H_

#define _ACPI_INTERNAL_H_



#include <linux/idr.h>



#define PREFIX "ACPI: "



int early_acpi_osi_init(void);
@@ -97,9 +99,11 @@ void acpi_scan_table_handler(u32 event, void *table, void *context); 


extern struct list_head acpi_bus_id_list;



#define ACPI_MAX_DEVICE_INSTANCES	4096



struct acpi_device_bus_id {

	const char *bus_id;

	unsigned int instance_no;

	struct ida instance_ida;

	struct list_head node;

};

drivers/acpi/scan.c

+28 −5
Original line number Diff line number Diff line
@@ -482,9 +482,8 @@ static void acpi_device_del(struct acpi_device *device) 
	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))) {

			if (acpi_device_bus_id->instance_no > 0)

				acpi_device_bus_id->instance_no--;

			else {

			ida_simple_remove(&acpi_device_bus_id->instance_ida, device->pnp.instance_no);

			if (ida_is_empty(&acpi_device_bus_id->instance_ida)) {

				list_del(&acpi_device_bus_id->node);

				kfree_const(acpi_device_bus_id->bus_id);

				kfree(acpi_device_bus_id);
@@ -635,6 +634,21 @@ static struct acpi_device_bus_id *acpi_device_bus_id_match(const char *dev_id) 
	return NULL;

}



static int acpi_device_set_name(struct acpi_device *device,

				struct acpi_device_bus_id *acpi_device_bus_id)

{

	struct ida *instance_ida = &acpi_device_bus_id->instance_ida;

	int result;



	result = ida_simple_get(instance_ida, 0, ACPI_MAX_DEVICE_INSTANCES, GFP_KERNEL);

	if (result < 0)

		return result;



	device->pnp.instance_no = result;

	dev_set_name(&device->dev, "%s:%02x", acpi_device_bus_id->bus_id, result);

	return 0;

}



int acpi_device_add(struct acpi_device *device,

		    void (*release)(struct device *))

{
@@ -669,7 +683,9 @@ int acpi_device_add(struct acpi_device *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++;

		result = acpi_device_set_name(device, acpi_device_bus_id);

		if (result)

			goto err_unlock;

	} else {

		acpi_device_bus_id = kzalloc(sizeof(*acpi_device_bus_id),

					     GFP_KERNEL);
@@ -685,9 +701,16 @@ int acpi_device_add(struct acpi_device *device, 
			goto err_unlock;

		}



		ida_init(&acpi_device_bus_id->instance_ida);



		result = acpi_device_set_name(device, acpi_device_bus_id);

		if (result) {

			kfree(acpi_device_bus_id);

			goto err_unlock;

		}



		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);



	if (device->parent)

		list_add_tail(&device->node, &device->parent->children);

include/acpi/acpi_bus.h

+1 −0
Original line number Diff line number Diff line
@@ -248,6 +248,7 @@ struct acpi_pnp_type { 


struct acpi_device_pnp {

	acpi_bus_id bus_id;		/* Object name */

	int instance_no;		/* Instance number of this object */

	struct acpi_pnp_type type;	/* ID type */

	acpi_bus_address bus_address;	/* _ADR */

	char *unique_id;		/* _UID */