On Wednesday, September 27, 2023 10:17:25 PM CEST Vicki Pfau wrote:
> This fixes a long-standing "TBD" comment in the ACPI headers regarding making
> the acpi_handle_list struct's size dynamic. The number 10, which along with the
> comment dates back to 2.4.23, seems like it may have been arbitrarily chosen,
> and isn't sufficient in all cases. This patch finally makes the size dynamic
> and updates its users to handle the modified API.
First off, the effort is definitely appreciated, because this is about
addressing a real issue seen in the field.
However, the users of acpi_handle_list should not need to care about its
internal structure, so functions should be provided for freeing it and
manipulating it as needed.
>
> Signed-off-by: Vicki Pfau <vi@xxxxxxxxxxx>
> ---
> drivers/acpi/acpi_lpss.c | 5 +++-
> drivers/acpi/scan.c | 1 +
> drivers/acpi/thermal.c | 23 ++++++++++++++-----
> drivers/acpi/utils.c | 5 ++--
> .../platform/surface/surface_acpi_notify.c | 5 +++-
> include/acpi/acpi_bus.h | 4 +---
> 6 files changed, 30 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c
> index 539e700de4d2..4b3aa84faf70 100644
> --- a/drivers/acpi/acpi_lpss.c
> +++ b/drivers/acpi/acpi_lpss.c
> @@ -591,10 +591,13 @@ static bool acpi_lpss_dep(struct acpi_device *adev, acpi_handle handle)
> }
>
> for (i = 0; i < dep_devices.count; i++) {
> - if (dep_devices.handles[i] == handle)
> + if (dep_devices.handles[i] == handle) {
> + kfree(dep_devices.handles);
> return true;
> + }
> }
>
> + kfree(dep_devices.handles);
Moreover, the code duplication here can be avoided by using a return variable.
> return false;
> }
>
> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> index 691d4b7686ee..2fbe354db0c0 100644
> --- a/drivers/acpi/scan.c
> +++ b/drivers/acpi/scan.c
> @@ -2032,6 +2032,7 @@ static u32 acpi_scan_check_dep(acpi_handle handle, bool check_dep)
> mutex_unlock(&acpi_dep_list_lock);
> }
>
> + kfree(dep_devices.handles);
> return count;
> }
>
> diff --git a/drivers/acpi/thermal.c b/drivers/acpi/thermal.c
> index 312730f8272e..48ddc56f96f6 100644
> --- a/drivers/acpi/thermal.c
> +++ b/drivers/acpi/thermal.c
> @@ -307,8 +307,10 @@ static void __acpi_thermal_trips_update(struct acpi_thermal *tz, int flag)
> tz->trips.passive.trip.valid = true;
> }
>
> - if (memcmp(&tz->trips.passive.devices, &devices,
> - sizeof(struct acpi_handle_list))) {
> + if (&tz->trips.passive.devices.count != devices.count ||
> + memcmp(tz->trips.passive.devices.handles,
> + devices.handles, sizeof(acpi_handle) * devices.count)) {
> + kfree(tz->trips.passive.devices.handles);
> memcpy(&tz->trips.passive.devices, &devices,
> sizeof(struct acpi_handle_list));
> ACPI_THERMAL_TRIPS_EXCEPTION(flag, tz, "device");
> @@ -372,8 +374,10 @@ static void __acpi_thermal_trips_update(struct acpi_thermal *tz, int flag)
> tz->trips.active[i].trip.valid = true;
> }
>
> - if (memcmp(&tz->trips.active[i].devices, &devices,
> - sizeof(struct acpi_handle_list))) {
> + if (&tz->trips.active[i].devices.count != devices.count ||
> + memcmp(tz->trips.active[i].devices.handles,
> + devices.handles, sizeof(acpi_handle) * devices.count)) {
> + kfree(tz->trips.active[i].devices.handles);
> memcpy(&tz->trips.active[i].devices, &devices,
> sizeof(struct acpi_handle_list));
> ACPI_THERMAL_TRIPS_EXCEPTION(flag, tz, "device");
> @@ -391,8 +395,10 @@ static void __acpi_thermal_trips_update(struct acpi_thermal *tz, int flag)
> memset(&devices, 0, sizeof(devices));
> status = acpi_evaluate_reference(tz->device->handle, "_TZD",
> NULL, &devices);
> - if (ACPI_SUCCESS(status) &&
> - memcmp(&tz->devices, &devices, sizeof(devices))) {
> + if (ACPI_SUCCESS(status) && (tz->devices.count != devices.count ||
> + memcmp(tz->devices.handles, devices.handles,
> + sizeof(acpi_handle) * devices.count))) {
> + kfree(tz->devices.handles);
> tz->devices = devices;
> ACPI_THERMAL_TRIPS_EXCEPTION(flag, tz, "device");
> }
All of the changes in thermal.c above need to be rebased on the ACPI thermal
changes currently in-flight, but that's something for me to take care of.
> @@ -974,6 +980,7 @@ static int acpi_thermal_add(struct acpi_device *device)
> static void acpi_thermal_remove(struct acpi_device *device)
> {
> struct acpi_thermal *tz;
> + int i;
>
> if (!device || !acpi_driver_data(device))
> return;
> @@ -986,6 +993,10 @@ static void acpi_thermal_remove(struct acpi_device *device)
> flush_workqueue(acpi_thermal_pm_queue);
> acpi_thermal_unregister_thermal_zone(tz);
>
> + kfree(tz->trips.passive.devices.handles);
> + for (i = 0; i < ACPI_THERMAL_MAX_ACTIVE; i++)
> + kfree(tz->trips.active[i].devices.handles);
> + kfree(tz->devices.handles);
And this also needs to be done in the acpi_thermal_add() error cleanup path
so as to avoid leaking memory from there.
> kfree(tz);
> }
>
> diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c
> index 2ea14648a661..96f821c41756 100644
> --- a/drivers/acpi/utils.c
> +++ b/drivers/acpi/utils.c
> @@ -370,7 +370,8 @@ acpi_evaluate_reference(acpi_handle handle,
> goto end;
> }
>
> - if (package->package.count > ACPI_MAX_HANDLES) {
> + list->handles = kcalloc(package->package.count, sizeof(*list->handles), GFP_KERNEL);
> + if (!list->handles) {
> kfree(package);
> return AE_NO_MEMORY;
> }
> @@ -402,7 +403,7 @@ acpi_evaluate_reference(acpi_handle handle,
> end:
> if (ACPI_FAILURE(status)) {
> list->count = 0;
> - //kfree(list->handles);
> + kfree(list->handles);
Clearing list->handles (to avoid leaking a stale pointer) here would be nice.
> }
>
> kfree(buffer.pointer);
> diff --git a/drivers/platform/surface/surface_acpi_notify.c b/drivers/platform/surface/surface_acpi_notify.c
> index 897cdd9c3aae..6932d4b35c6c 100644
> --- a/drivers/platform/surface/surface_acpi_notify.c
> +++ b/drivers/platform/surface/surface_acpi_notify.c
> @@ -753,10 +753,13 @@ static bool is_san_consumer(struct platform_device *pdev, acpi_handle handle)
> }
>
> for (i = 0; i < dep_devices.count; i++) {
> - if (dep_devices.handles[i] == supplier)
> + if (dep_devices.handles[i] == supplier) {
> + kfree(dep_devices.handles);
> return true;
> + }
> }
>
> + kfree(dep_devices.handles);
> return false;
And again, the code duplication here is avoidable.
> }
>
> diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
> index 254685085c82..b4bf12343a22 100644
> --- a/include/acpi/acpi_bus.h
> +++ b/include/acpi/acpi_bus.h
> @@ -12,11 +12,9 @@
> #include <linux/device.h>
> #include <linux/property.h>
>
> -/* TBD: Make dynamic */
> -#define ACPI_MAX_HANDLES 10
> struct acpi_handle_list {
> u32 count;
> - acpi_handle handles[ACPI_MAX_HANDLES];
> + acpi_handle* handles;
> };
>
> /* acpi_utils.h */
>
All of the above said, I don't really want to defer making this change
too much, so below is my version of it (with the Co-developed-by tag
pointing to you and your S-o-b as the co-author of the changes) and
this is what I'm going to apply unless somebody is able to poke a hole
in it.
---
Subject: [PATCH] ACPI: utils: Dynamically determine acpi_handle_list size
From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Address a long-standing "TBD" comment in the ACPI headers regarding the
number of handles in struct acpi_handle_list.
The number 10, which along with the comment dates back to 2.4.23, seems
like it may have been arbitrarily chosen and isn't sufficient in all
cases [1].
Finally change the code to dynamically determine the size of the handles
table in struct acpi_handle_list and allocate it accordingly.
Update the users of to struct acpi_handle_list to take the additional
dynamic allocation into account.
Link: https://lore.kernel.org/linux-acpi/20230809094451.15473-1-ivan.hu@xxxxxxxxxxxxx # [1]
Co-developed-by: Vicki Pfau <vi@xxxxxxxxxxx>
Signed-off-by: Vicki Pfau <vi@xxxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
This applies on top of
https://patchwork.kernel.org/project/linux-pm/patch/1785516.VLH7GnMWUR@kreacher/
---
drivers/acpi/acpi_lpss.c | 10 ++--
drivers/acpi/scan.c | 1
drivers/acpi/thermal.c | 28 ++++++++---
drivers/acpi/utils.c | 61 ++++++++++++++++++++++++-
drivers/platform/surface/surface_acpi_notify.c | 10 ++--
include/acpi/acpi_bus.h | 9 ++-
6 files changed, 101 insertions(+), 18 deletions(-)
Index: linux-pm/drivers/acpi/acpi_lpss.c
===================================================================
--- linux-pm.orig/drivers/acpi/acpi_lpss.c
+++ linux-pm/drivers/acpi/acpi_lpss.c
@@ -578,6 +578,7 @@ static bool acpi_lpss_dep(struct acpi_de
{
struct acpi_handle_list dep_devices;
acpi_status status;
+ bool ret = false;
int i;
if (!acpi_has_method(adev->handle, "_DEP"))
@@ -591,11 +592,14 @@ static bool acpi_lpss_dep(struct acpi_de
}
for (i = 0; i < dep_devices.count; i++) {
- if (dep_devices.handles[i] == handle)
- return true;
+ if (dep_devices.handles[i] == handle) {
+ ret = true;
+ break;
+ }
}
- return false;
+ acpi_handle_list_free(&dep_devices);
+ return ret;
}
static void acpi_lpss_link_consumer(struct device *dev1,
Index: linux-pm/drivers/acpi/scan.c
===================================================================
--- linux-pm.orig/drivers/acpi/scan.c
+++ linux-pm/drivers/acpi/scan.c
@@ -2031,6 +2031,7 @@ static u32 acpi_scan_check_dep(acpi_hand
mutex_unlock(&acpi_dep_list_lock);
}
+ acpi_handle_list_free(&dep_devices);
return count;
}
Index: linux-pm/drivers/acpi/thermal.c
===================================================================
--- linux-pm.orig/drivers/acpi/thermal.c
+++ linux-pm/drivers/acpi/thermal.c
@@ -208,7 +208,7 @@ static bool update_trip_devices(struct a
struct acpi_thermal_trip *acpi_trip,
int index, bool compare)
{
- struct acpi_handle_list devices;
+ struct acpi_handle_list devices = { 0 };
char method[] = "_PSL";
acpi_status status;
@@ -218,18 +218,21 @@ static bool update_trip_devices(struct a
method[3] = '0' + index;
}
- memset(&devices, 0, sizeof(devices));
-
status = acpi_evaluate_reference(tz->device->handle, method, NULL, &devices);
if (ACPI_FAILURE(status)) {
acpi_handle_info(tz->device->handle, "%s evaluation failure\n", method);
return false;
}
- if (compare && memcmp(&acpi_trip->devices, &devices, sizeof(devices)))
+ if (acpi_handle_list_equal(&acpi_trip->devices, &devices)) {
+ acpi_handle_list_free(&devices);
+ return true;
+ }
+
+ if (compare)
ACPI_THERMAL_TRIPS_EXCEPTION(tz, "device");
- memcpy(&acpi_trip->devices, &devices, sizeof(devices));
+ acpi_handle_list_replace(&acpi_trip->devices, &devices);
return true;
}
@@ -845,6 +848,17 @@ static void acpi_thermal_check_fn(struct
mutex_unlock(&tz->thermal_check_lock);
}
+static void acpi_thermal_free_thermal_zone(struct acpi_thermal *tz)
+{
+ int i;
+
+ acpi_handle_list_free(&tz->trips.passive.trip.devices);
+ for (i = 0; i < ACPI_THERMAL_MAX_ACTIVE; i++)
+ acpi_handle_list_free(&tz->trips.active[i].trip.devices);
+
+ kfree(tz);
+}
+
static int acpi_thermal_add(struct acpi_device *device)
{
struct acpi_thermal_trip *acpi_trip;
@@ -971,7 +985,7 @@ flush_wq:
free_trips:
kfree(tz->trip_table);
free_memory:
- kfree(tz);
+ acpi_thermal_free_thermal_zone(tz);
return result;
}
@@ -991,7 +1005,7 @@ static void acpi_thermal_remove(struct a
flush_workqueue(acpi_thermal_pm_queue);
acpi_thermal_unregister_thermal_zone(tz);
- kfree(tz);
+ acpi_thermal_free_thermal_zone(tz);
}
#ifdef CONFIG_PM_SLEEP
Index: linux-pm/drivers/acpi/utils.c
===================================================================
--- linux-pm.orig/drivers/acpi/utils.c
+++ linux-pm/drivers/acpi/utils.c
@@ -370,7 +370,8 @@ acpi_evaluate_reference(acpi_handle hand
goto end;
}
- if (package->package.count > ACPI_MAX_HANDLES) {
+ list->handles = kcalloc(package->package.count, sizeof(*list->handles), GFP_KERNEL);
+ if (!list->handles) {
kfree(package);
return AE_NO_MEMORY;
}
@@ -402,7 +403,8 @@ acpi_evaluate_reference(acpi_handle hand
end:
if (ACPI_FAILURE(status)) {
list->count = 0;
- //kfree(list->handles);
+ kfree(list->handles);
+ list->handles = NULL;
}
kfree(buffer.pointer);
@@ -412,6 +414,61 @@ acpi_evaluate_reference(acpi_handle hand
EXPORT_SYMBOL(acpi_evaluate_reference);
+/**
+ * acpi_handle_list_equal - Check if two ACPI handle lists are the same
+ * @list1: First list to compare.
+ * @List2: Second list to compare.
+ *
+ * Return true if the given ACPI handle lists are of the same size and
+ * contain the same ACPI handles in the same order. Otherwise, return false.
+ */
+bool acpi_handle_list_equal(struct acpi_handle_list *list1,
+ struct acpi_handle_list *list2)
+{
+ return list1->count == list2->count &&
+ !memcmp(list1->handles, list2->handles,
+ list1->count * sizeof(acpi_handle));
+}
+EXPORT_SYMBOL_GPL(acpi_handle_list_equal);
+
+/**
+ * acpi_handle_list_replace - Replace one ACPI handle list with another
+ * @dst: ACPI handle list to replace.
+ * @src: Source ACPI handle list.
+ *
+ * Free the handles table in @dst, move the handles table from @src to @dst,
+ * copy count from @src to @dst and clear @src.
+ */
+void acpi_handle_list_replace(struct acpi_handle_list *dst,
+ struct acpi_handle_list *src)
+{
+ if (dst->count)
+ kfree(dst->handles);
+
+ dst->count = src->count;
+ dst->handles = src->handles;
+
+ src->handles = NULL;
+ src->count = 0;
+}
+EXPORT_SYMBOL_GPL(acpi_handle_list_replace);
+
+/**
+ * acpi_handle_list_free - Free the handles table in an ACPI handle list
+ * @list: ACPI handle list to free.
+ *
+ * Free the handles table in @list and clear its count field.
+ */
+void acpi_handle_list_free(struct acpi_handle_list *list)
+{
+ if (!list->count)
+ return;
+
+ kfree(list->handles);
+ list->count = 0;
+}
+EXPORT_SYMBOL_GPL(acpi_handle_list_free);
+
acpi_status
acpi_get_physical_device_location(acpi_handle handle, struct acpi_pld_info **pld)
{
Index: linux-pm/drivers/platform/surface/surface_acpi_notify.c
===================================================================
--- linux-pm.orig/drivers/platform/surface/surface_acpi_notify.c
+++ linux-pm/drivers/platform/surface/surface_acpi_notify.c
@@ -741,6 +741,7 @@ static bool is_san_consumer(struct platf
struct acpi_handle_list dep_devices;
acpi_handle supplier = ACPI_HANDLE(&pdev->dev);
acpi_status status;
+ bool ret = false;
int i;
if (!acpi_has_method(handle, "_DEP"))
@@ -753,11 +754,14 @@ static bool is_san_consumer(struct platf
}
for (i = 0; i < dep_devices.count; i++) {
- if (dep_devices.handles[i] == supplier)
- return true;
+ if (dep_devices.handles[i] == supplier) {
+ ret = true;
+ break;
+ }
}
- return false;
+ acpi_handle_list_free(&dep_devices);
+ return ret;
}
static acpi_status san_consumer_setup(acpi_handle handle, u32 lvl,
Index: linux-pm/include/acpi/acpi_bus.h
===================================================================
--- linux-pm.orig/include/acpi/acpi_bus.h
+++ linux-pm/include/acpi/acpi_bus.h
@@ -12,11 +12,9 @@
#include <linux/device.h>
#include <linux/property.h>
-/* TBD: Make dynamic */
-#define ACPI_MAX_HANDLES 10
struct acpi_handle_list {
u32 count;
- acpi_handle handles[ACPI_MAX_HANDLES];
+ acpi_handle* handles;
};
/* acpi_utils.h */
@@ -32,6 +30,11 @@ acpi_evaluate_reference(acpi_handle hand
acpi_string pathname,
struct acpi_object_list *arguments,
struct acpi_handle_list *list);
+bool acpi_handle_list_equal(struct acpi_handle_list *list1,
+ struct acpi_handle_list *list2);
+void acpi_handle_list_replace(struct acpi_handle_list *dst,
+ struct acpi_handle_list *src);
+void acpi_handle_list_free(struct acpi_handle_list *list);
acpi_status
acpi_evaluate_ost(acpi_handle handle, u32 source_event, u32 status_code,
struct acpi_buffer *status_buf);
