[PATCH 4.14 49/59] ACPI: scan: Use unique number for instance_no

Greg Kroah-Hartman
2021-03-29T08:10:33Z

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

[ 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: e49bd2dd5a50 ("ACPI: use PNPID:instance_no as bus_id of ACPI device")
Fixes: ca9dc8d42b30 ("ACPI / scan: Fix acpi_bus_id_list bookkeeping")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: 4.10+ <stable@vger.kernel.org> # 4.10+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/acpi/internal.h | 6 +++++-
drivers/acpi/scan.c | 33 ++++++++++++++++++++++++++++-----
include/acpi/acpi_bus.h | 1 +
3 files changed, 34 insertions(+), 6 deletions(-)

diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index e6b10aad55d5..6ac1c6b04199 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -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;
};

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 9ec463da9a50..57a213466721 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -481,9 +481,8 @@ 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);
@@ -634,6 +633,21 @@ 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 *))
{
@@ -668,7 +682,9 @@ 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);
@@ -684,9 +700,16 @@ 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);
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 67f4fce22209..3746d4ce4857 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -245,6 +245,7 @@ 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 */
--
2.30.1