2024-06-13 20:15:48

by Thomas Weißschuh

[permalink] [raw]
Subject: [PATCH 0/5] ACPI: sysfs: manage sysfs attributes through device core

Simplify the lifecycle of the sysfs attributes by letting the device
core manage them.

Signed-off-by: Thomas Weißschuh <[email protected]>
---
Thomas Weißschuh (5):
ACPI: sysfs: convert utf-16 from _STR to utf-8 only once
ACPI: sysfs: use device lifecycle for _STR result
ACPI: sysfs: manage attributes as attribute_group
ACPI: sysfs: manage sysfs attributes through device core
ACPI: sysfs: remove return value of acpi_device_setup_files()

drivers/acpi/device_sysfs.c | 229 +++++++++++++++++++++-----------------------
drivers/acpi/internal.h | 3 +-
drivers/acpi/scan.c | 6 +-
include/acpi/acpi_bus.h | 2 +-
4 files changed, 114 insertions(+), 126 deletions(-)
---
base-commit: 7d91551085d3e7d5eb21c2481565b2be5288f11b
change-id: 20240609-acpi-sysfs-groups-cfa756d16752

Best regards,
--
Thomas Weißschuh <[email protected]>



2024-06-13 20:15:52

by Thomas Weißschuh

[permalink] [raw]
Subject: [PATCH 3/5] ACPI: sysfs: manage attributes as attribute_group

The current manual attribute management is inconsistent and brittle.
Not all return values of device_create_file() are checked and the
cleanup logic needs to be kept up to date manually.

Moving all attributes into an attribute_group and using the is_visible()
callback allows the management of all attributes as a single unit.

Signed-off-by: Thomas Weißschuh <[email protected]>
---
drivers/acpi/device_sysfs.c | 190 ++++++++++++++++++++------------------------
1 file changed, 84 insertions(+), 106 deletions(-)

diff --git a/drivers/acpi/device_sysfs.c b/drivers/acpi/device_sysfs.c
index d0ca159d93e1..a673488066b3 100644
--- a/drivers/acpi/device_sysfs.c
+++ b/drivers/acpi/device_sysfs.c
@@ -494,6 +494,88 @@ static ssize_t status_show(struct device *dev, struct device_attribute *attr,
}
static DEVICE_ATTR_RO(status);

+static struct attribute *acpi_attrs[] = {
+ &dev_attr_path.attr,
+ &dev_attr_hid.attr,
+ &dev_attr_modalias.attr,
+ &dev_attr_description.attr,
+ &dev_attr_adr.attr,
+ &dev_attr_uid.attr,
+ &dev_attr_sun.attr,
+ &dev_attr_hrv.attr,
+ &dev_attr_status.attr,
+ &dev_attr_eject.attr,
+ &dev_attr_power_state.attr,
+ &dev_attr_real_power_state.attr,
+ NULL
+};
+
+static bool acpi_show_attr(struct acpi_device *dev, const struct device_attribute *attr)
+{
+ /*
+ * Devices gotten from FADT don't have a "path" attribute
+ */
+ if (attr == &dev_attr_path)
+ return dev->handle;
+
+ if (attr == &dev_attr_hid || attr == &dev_attr_modalias)
+ return !list_empty(&dev->pnp.ids);
+
+ /*
+ * If device has _STR, 'description' file is created
+ */
+ if (attr == &dev_attr_description)
+ return dev->pnp.str;
+
+ if (attr == &dev_attr_adr)
+ return dev->pnp.type.bus_address;
+
+ if (attr == &dev_attr_uid)
+ return acpi_device_uid(dev);
+
+ if (attr == &dev_attr_sun)
+ return acpi_has_method(dev->handle, "_SUN");
+
+ if (attr == &dev_attr_hrv)
+ return acpi_has_method(dev->handle, "_HRV");
+
+ if (attr == &dev_attr_status)
+ return acpi_has_method(dev->handle, "_STA");
+
+ /*
+ * If device has _EJ0, 'eject' file is created that is used to trigger
+ * hot-removal function from userland.
+ */
+ if (attr == &dev_attr_eject)
+ return acpi_has_method(dev->handle, "_EJ0");
+
+ if (attr == &dev_attr_power_state)
+ return dev->flags.power_manageable;
+
+ if (attr == &dev_attr_real_power_state)
+ return dev->flags.power_manageable && dev->power.flags.power_resources;
+
+ dev_warn_once(&dev->dev, "Unexpected attribute: %s\n", attr->attr.name);
+ return false;
+}
+
+static umode_t acpi_attr_is_visible(struct kobject *kobj,
+ struct attribute *attr,
+ int attrno)
+{
+ struct acpi_device *dev = to_acpi_device(kobj_to_dev(kobj));
+
+ if (acpi_show_attr(dev, container_of(attr, struct device_attribute, attr)))
+ return attr->mode;
+ else
+ return 0;
+}
+
+static const struct attribute_group acpi_group = {
+ .attrs = acpi_attrs,
+ .is_visible = acpi_attr_is_visible,
+};
+
static const char *devm_acpi_device_str(struct acpi_device *dev)
{
struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
@@ -536,81 +618,11 @@ int acpi_device_setup_files(struct acpi_device *dev)
{
int result = 0;

- /*
- * Devices gotten from FADT don't have a "path" attribute
- */
- if (dev->handle) {
- result = device_create_file(&dev->dev, &dev_attr_path);
- if (result)
- goto end;
- }
-
- if (!list_empty(&dev->pnp.ids)) {
- result = device_create_file(&dev->dev, &dev_attr_hid);
- if (result)
- goto end;
-
- result = device_create_file(&dev->dev, &dev_attr_modalias);
- if (result)
- goto end;
- }
-
- /*
- * If device has _STR, 'description' file is created
- */
dev->pnp.str = devm_acpi_device_str(dev);
- if (dev->pnp.str) {
- result = device_create_file(&dev->dev, &dev_attr_description);
- if (result)
- goto end;
- }
-
- if (dev->pnp.type.bus_address)
- result = device_create_file(&dev->dev, &dev_attr_adr);
- if (acpi_device_uid(dev))
- result = device_create_file(&dev->dev, &dev_attr_uid);
-
- if (acpi_has_method(dev->handle, "_SUN")) {
- result = device_create_file(&dev->dev, &dev_attr_sun);
- if (result)
- goto end;
- }
-
- if (acpi_has_method(dev->handle, "_HRV")) {
- result = device_create_file(&dev->dev, &dev_attr_hrv);
- if (result)
- goto end;
- }
-
- if (acpi_has_method(dev->handle, "_STA")) {
- result = device_create_file(&dev->dev, &dev_attr_status);
- if (result)
- goto end;
- }
-
- /*
- * If device has _EJ0, 'eject' file is created that is used to trigger
- * hot-removal function from userland.
- */
- if (acpi_has_method(dev->handle, "_EJ0")) {
- result = device_create_file(&dev->dev, &dev_attr_eject);
- if (result)
- return result;
- }
-
- if (dev->flags.power_manageable) {
- result = device_create_file(&dev->dev, &dev_attr_power_state);
- if (result)
- return result;
-
- if (dev->power.flags.power_resources)
- result = device_create_file(&dev->dev,
- &dev_attr_real_power_state);
- }
+ result = device_add_group(&dev->dev, &acpi_group);

acpi_expose_nondev_subnodes(&dev->dev.kobj, &dev->data);

-end:
return result;
}

@@ -621,39 +633,5 @@ int acpi_device_setup_files(struct acpi_device *dev)
void acpi_device_remove_files(struct acpi_device *dev)
{
acpi_hide_nondev_subnodes(&dev->data);
-
- if (dev->flags.power_manageable) {
- device_remove_file(&dev->dev, &dev_attr_power_state);
- if (dev->power.flags.power_resources)
- device_remove_file(&dev->dev,
- &dev_attr_real_power_state);
- }
-
- /*
- * If device has _STR, remove 'description' file
- */
- if (acpi_has_method(dev->handle, "_STR"))
- device_remove_file(&dev->dev, &dev_attr_description);
- /*
- * If device has _EJ0, remove 'eject' file.
- */
- if (acpi_has_method(dev->handle, "_EJ0"))
- device_remove_file(&dev->dev, &dev_attr_eject);
-
- if (acpi_has_method(dev->handle, "_SUN"))
- device_remove_file(&dev->dev, &dev_attr_sun);
-
- if (acpi_has_method(dev->handle, "_HRV"))
- device_remove_file(&dev->dev, &dev_attr_hrv);
-
- if (acpi_device_uid(dev))
- device_remove_file(&dev->dev, &dev_attr_uid);
- if (dev->pnp.type.bus_address)
- device_remove_file(&dev->dev, &dev_attr_adr);
- device_remove_file(&dev->dev, &dev_attr_modalias);
- device_remove_file(&dev->dev, &dev_attr_hid);
- if (acpi_has_method(dev->handle, "_STA"))
- device_remove_file(&dev->dev, &dev_attr_status);
- if (dev->handle)
- device_remove_file(&dev->dev, &dev_attr_path);
+ device_remove_group(&dev->dev, &acpi_group);
}

--
2.45.2


2024-06-13 20:16:36

by Thomas Weißschuh

[permalink] [raw]
Subject: [PATCH 4/5] ACPI: sysfs: manage sysfs attributes through device core

Now that the acpi sysfs attributes are organized around an
attribute_group the device core can manage them.

Signed-off-by: Thomas Weißschuh <[email protected]>
---
drivers/acpi/device_sysfs.c | 8 +++++---
drivers/acpi/internal.h | 1 +
drivers/acpi/scan.c | 1 +
3 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/device_sysfs.c b/drivers/acpi/device_sysfs.c
index a673488066b3..f1e8928254c2 100644
--- a/drivers/acpi/device_sysfs.c
+++ b/drivers/acpi/device_sysfs.c
@@ -576,6 +576,11 @@ static const struct attribute_group acpi_group = {
.is_visible = acpi_attr_is_visible,
};

+const struct attribute_group *acpi_groups[] = {
+ &acpi_group,
+ NULL
+};
+
static const char *devm_acpi_device_str(struct acpi_device *dev)
{
struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
@@ -619,8 +624,6 @@ int acpi_device_setup_files(struct acpi_device *dev)
int result = 0;

dev->pnp.str = devm_acpi_device_str(dev);
- result = device_add_group(&dev->dev, &acpi_group);
-
acpi_expose_nondev_subnodes(&dev->dev.kobj, &dev->data);

return result;
@@ -633,5 +636,4 @@ int acpi_device_setup_files(struct acpi_device *dev)
void acpi_device_remove_files(struct acpi_device *dev)
{
acpi_hide_nondev_subnodes(&dev->data);
- device_remove_group(&dev->dev, &acpi_group);
}
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 2a0e9fc7b74c..63dd78d80508 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -120,6 +120,7 @@ int acpi_tie_acpi_dev(struct acpi_device *adev);
int acpi_device_add(struct acpi_device *device);
int acpi_device_setup_files(struct acpi_device *dev);
void acpi_device_remove_files(struct acpi_device *dev);
+extern const struct attribute_group *acpi_groups[];
void acpi_device_add_finalize(struct acpi_device *device);
void acpi_free_pnp_ids(struct acpi_device_pnp *pnp);
bool acpi_device_is_enabled(const struct acpi_device *adev);
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 503773707e01..c15fffefca0a 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1813,6 +1813,7 @@ void acpi_init_device_object(struct acpi_device *device, acpi_handle handle,
device->dev.parent = parent ? &parent->dev : NULL;
device->dev.release = release;
device->dev.bus = &acpi_bus_type;
+ device->dev.groups = acpi_groups;
fwnode_init(&device->fwnode, &acpi_device_fwnode_ops);
acpi_set_device_status(device, ACPI_STA_DEFAULT);
acpi_device_get_busid(device);

--
2.45.2


2024-06-13 20:16:39

by Thomas Weißschuh

[permalink] [raw]
Subject: [PATCH 5/5] ACPI: sysfs: remove return value of acpi_device_setup_files()

The function can not fail anymore, so drop its return value.

Signed-off-by: Thomas Weißschuh <[email protected]>
---
drivers/acpi/device_sysfs.c | 6 +-----
drivers/acpi/internal.h | 2 +-
drivers/acpi/scan.c | 5 +----
3 files changed, 3 insertions(+), 10 deletions(-)

diff --git a/drivers/acpi/device_sysfs.c b/drivers/acpi/device_sysfs.c
index f1e8928254c2..c85ec754931c 100644
--- a/drivers/acpi/device_sysfs.c
+++ b/drivers/acpi/device_sysfs.c
@@ -619,14 +619,10 @@ static const char *devm_acpi_device_str(struct acpi_device *dev)
* acpi_device_setup_files - Create sysfs attributes of an ACPI device.
* @dev: ACPI device object.
*/
-int acpi_device_setup_files(struct acpi_device *dev)
+void acpi_device_setup_files(struct acpi_device *dev)
{
- int result = 0;
-
dev->pnp.str = devm_acpi_device_str(dev);
acpi_expose_nondev_subnodes(&dev->dev.kobj, &dev->data);
-
- return result;
}

/**
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 63dd78d80508..e71fecbf731c 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -118,7 +118,7 @@ void acpi_init_device_object(struct acpi_device *device, acpi_handle handle,
int type, void (*release)(struct device *));
int acpi_tie_acpi_dev(struct acpi_device *adev);
int acpi_device_add(struct acpi_device *device);
-int acpi_device_setup_files(struct acpi_device *dev);
+void acpi_device_setup_files(struct acpi_device *dev);
void acpi_device_remove_files(struct acpi_device *dev);
extern const struct attribute_group *acpi_groups[];
void acpi_device_add_finalize(struct acpi_device *device);
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index c15fffefca0a..49a8172fe0de 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -766,10 +766,7 @@ int acpi_device_add(struct acpi_device *device)
goto err;
}

- result = acpi_device_setup_files(device);
- if (result)
- pr_err("Error creating sysfs interface for device %s\n",
- dev_name(&device->dev));
+ acpi_device_setup_files(device);

return 0;


--
2.45.2


2024-06-13 20:34:20

by Thomas Weißschuh

[permalink] [raw]
Subject: [PATCH 2/5] ACPI: sysfs: use device lifecycle for _STR result

The string assigned to dev->pnp.str effectively shares the lifetime of
the device. Use devm_-APIs to avoid a manual cleanup path.

This will be useful when the attributes themselves will be managed by
the device core.

Signed-off-by: Thomas Weißschuh <[email protected]>
---
drivers/acpi/device_sysfs.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/acpi/device_sysfs.c b/drivers/acpi/device_sysfs.c
index 4bedbe8f57ed..d0ca159d93e1 100644
--- a/drivers/acpi/device_sysfs.c
+++ b/drivers/acpi/device_sysfs.c
@@ -494,7 +494,7 @@ static ssize_t status_show(struct device *dev, struct device_attribute *attr,
}
static DEVICE_ATTR_RO(status);

-static const char *acpi_device_str(struct acpi_device *dev)
+static const char *devm_acpi_device_str(struct acpi_device *dev)
{
struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
union acpi_object *str_obj;
@@ -522,7 +522,7 @@ static const char *acpi_device_str(struct acpi_device *dev)
buf, sizeof(buf) - 1);
buf[result++] = '\0';

- ret = kstrdup(buf, GFP_KERNEL);
+ ret = devm_kstrdup(&dev->dev, buf, GFP_KERNEL);
kfree(buffer.pointer);

return ret;
@@ -558,7 +558,7 @@ int acpi_device_setup_files(struct acpi_device *dev)
/*
* If device has _STR, 'description' file is created
*/
- dev->pnp.str = acpi_device_str(dev);
+ dev->pnp.str = devm_acpi_device_str(dev);
if (dev->pnp.str) {
result = device_create_file(&dev->dev, &dev_attr_description);
if (result)
@@ -632,10 +632,8 @@ void acpi_device_remove_files(struct acpi_device *dev)
/*
* If device has _STR, remove 'description' file
*/
- if (acpi_has_method(dev->handle, "_STR")) {
- kfree(dev->pnp.str);
+ if (acpi_has_method(dev->handle, "_STR"))
device_remove_file(&dev->dev, &dev_attr_description);
- }
/*
* If device has _EJ0, remove 'eject' file.
*/

--
2.45.2


2024-06-13 20:34:29

by Thomas Weißschuh

[permalink] [raw]
Subject: [PATCH 1/5] ACPI: sysfs: convert utf-16 from _STR to utf-8 only once

The ACPI _STR method returns an UTF-16 string that is converted to utf-8
before printing it in sysfs.
Currently this conversion is performed every time the "description"
sysfs attribute is read, which is not necessary.

Only perform the conversion once and cache the result.

Signed-off-by: Thomas Weißschuh <[email protected]>
---
drivers/acpi/device_sysfs.c | 63 ++++++++++++++++++++++++++++-----------------
include/acpi/acpi_bus.h | 2 +-
2 files changed, 40 insertions(+), 25 deletions(-)

diff --git a/drivers/acpi/device_sysfs.c b/drivers/acpi/device_sysfs.c
index 23373faa35ec..4bedbe8f57ed 100644
--- a/drivers/acpi/device_sysfs.c
+++ b/drivers/acpi/device_sysfs.c
@@ -439,24 +439,11 @@ static ssize_t description_show(struct device *dev,
char *buf)
{
struct acpi_device *acpi_dev = to_acpi_device(dev);
- int result;

- if (acpi_dev->pnp.str_obj == NULL)
+ if (acpi_dev->pnp.str == NULL)
return 0;

- /*
- * The _STR object contains a Unicode identifier for a device.
- * We need to convert to utf-8 so it can be displayed.
- */
- result = utf16s_to_utf8s(
- (wchar_t *)acpi_dev->pnp.str_obj->buffer.pointer,
- acpi_dev->pnp.str_obj->buffer.length,
- UTF16_LITTLE_ENDIAN, buf,
- PAGE_SIZE - 1);
-
- buf[result++] = '\n';
-
- return result;
+ return sysfs_emit("%s\n", acpi_dev->pnp.str);
}
static DEVICE_ATTR_RO(description);

@@ -507,14 +494,46 @@ static ssize_t status_show(struct device *dev, struct device_attribute *attr,
}
static DEVICE_ATTR_RO(status);

+static const char *acpi_device_str(struct acpi_device *dev)
+{
+ struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
+ union acpi_object *str_obj;
+ acpi_status status;
+ const char *ret;
+ char buf[512];
+ int result;
+
+ if (!acpi_has_method(dev->handle, "_STR"))
+ return NULL;
+
+ status = acpi_evaluate_object(dev->handle, "_STR",
+ NULL, &buffer);
+ if (ACPI_FAILURE(status))
+ return NULL;
+
+ str_obj = buffer.pointer;
+ /*
+ * The _STR object contains a Unicode identifier for a device.
+ * We need to convert to utf-8 so it can be displayed.
+ */
+ result = utf16s_to_utf8s((wchar_t *)str_obj->buffer.pointer,
+ str_obj->buffer.length,
+ UTF16_LITTLE_ENDIAN,
+ buf, sizeof(buf) - 1);
+ buf[result++] = '\0';
+
+ ret = kstrdup(buf, GFP_KERNEL);
+ kfree(buffer.pointer);
+
+ return ret;
+}
+
/**
* acpi_device_setup_files - Create sysfs attributes of an ACPI device.
* @dev: ACPI device object.
*/
int acpi_device_setup_files(struct acpi_device *dev)
{
- struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
- acpi_status status;
int result = 0;

/*
@@ -539,12 +558,8 @@ int acpi_device_setup_files(struct acpi_device *dev)
/*
* If device has _STR, 'description' file is created
*/
- if (acpi_has_method(dev->handle, "_STR")) {
- status = acpi_evaluate_object(dev->handle, "_STR",
- NULL, &buffer);
- if (ACPI_FAILURE(status))
- buffer.pointer = NULL;
- dev->pnp.str_obj = buffer.pointer;
+ dev->pnp.str = acpi_device_str(dev);
+ if (dev->pnp.str) {
result = device_create_file(&dev->dev, &dev_attr_description);
if (result)
goto end;
@@ -618,7 +633,7 @@ void acpi_device_remove_files(struct acpi_device *dev)
* If device has _STR, remove 'description' file
*/
if (acpi_has_method(dev->handle, "_STR")) {
- kfree(dev->pnp.str_obj);
+ kfree(dev->pnp.str);
device_remove_file(&dev->dev, &dev_attr_description);
}
/*
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 1a4dfd7a1c4a..32e3105c9ece 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -254,7 +254,7 @@ struct acpi_device_pnp {
struct list_head ids; /* _HID and _CIDs */
acpi_device_name device_name; /* Driver-determined */
acpi_device_class device_class; /* " */
- union acpi_object *str_obj; /* unicode string for _STR method */
+ const char *str; /* _STR */
};

#define acpi_device_bid(d) ((d)->pnp.bus_id)

--
2.45.2