ACPI: scan: Use unique number for instance_no

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>

diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index e6a5d997241c43d803d9758b01328db8b6cdb0cc..cb8f70842249e3cb9da68e0fe9de903a91203498 100644 (file)
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -9,6 +9,8 @@
 #ifndef _ACPI_INTERNAL_H_
 #define _ACPI_INTERNAL_H_
 
+#include <linux/idr.h>
+
 #define PREFIX "ACPI: "
 
 int early_acpi_osi_init(void);
@@ -96,9 +98,11 @@ 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 a184529d8fa402f077790cbfa04094e7724c6c9a..84bb7c1929f13def596d49a4243212f93c905cdb 100644 (file)
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -479,9 +479,8 @@ 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);
@@ -631,6 +630,21 @@ 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 *))
 {
@@ -665,7 +679,9 @@ 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);
@@ -681,9 +697,16 @@ 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 02a716a0af5d4950f5f43d5a2e39a9bc36b351f4..f28b097c658f474c89c071d80de7391809afdc67 100644 (file)
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -233,6 +233,7 @@ 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 */