[RFC PATCH 2/3] ACPI: scan: add cancel_eject and auto_eject attributes

From: Chester Lin
Date: Fri Mar 27 2020 - 07:29:00 EST

Add two attributes 'cancel_eject' and 'auto_eject' as auxiliary features of
request_offline, which are only effective when the request_offline is set.
Writing 1 to cancel_eject will remove pending the eject event and then put
the target back to its original online state if it has been changed.
Writing a time interval to auto_eject will periodically schedule an eject
event and will trigger real hot-remove once the target is offline. You can
still keep auto_eject to 0 if the firmware or userpsace caller who raises
the eject request can re-trigger an eject event by itself.

Signed-off-by: Chester Lin <clin@xxxxxxxx>
---
Documentation/ABI/testing/sysfs-bus-acpi | 20 ++++++
drivers/acpi/device_sysfs.c | 87 +++++++++++++++++++++++-
drivers/acpi/internal.h | 2 +
drivers/acpi/osl.c | 37 ++++++++--
drivers/acpi/scan.c | 53 +++++++++++++--
include/acpi/acpi_bus.h | 9 ++-
6 files changed, 193 insertions(+), 15 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-bus-acpi b/Documentation/ABI/testing/sysfs-bus-acpi
index b9c467704889..be00749f00e6 100644
--- a/Documentation/ABI/testing/sysfs-bus-acpi
+++ b/Documentation/ABI/testing/sysfs-bus-acpi
@@ -109,3 +109,23 @@ Description:
operations before the target can be ejected. This approach
provides flexibility while some applications could need more
time to release resources.
+
+What: /sys/bus/acpi/devices/.../cancel_eject
+Date: Mar, 2020
+Contact: Chester Lin <clin@xxxxxxxx>
+Description:
+ (WO) Writing 1 to this attribute will cancel the pending
+ ejection when userland is working on a target's offline
+ procedure [e.g. req_offline is set]. Then it will try putting
+ the target device back to its original online state.
+
+What: /sys/bus/acpi/devices/.../auto_eject
+Date: Mar, 2020
+Contact: Chester Lin <clin@xxxxxxxx>
+Description:
+ (RW) Allows the userland to periodically schedule an eject
+ event on a target until it can be successfully removed.
+ Userland can write a time interval [unit: second] to this
+ attribute, and write 0 to disable it. This feature is disabled
+ when the request_offline is 0 or no initial eject event
+ is triggered by firmware or an eject attribute in /sys.
diff --git a/drivers/acpi/device_sysfs.c b/drivers/acpi/device_sysfs.c
index 453bd1b9edf5..e40daafa3f85 100644
--- a/drivers/acpi/device_sysfs.c
+++ b/drivers/acpi/device_sysfs.c
@@ -511,7 +511,7 @@ static ssize_t request_offline_show(struct device *dev,
{
struct acpi_device *acpi_dev = to_acpi_device(dev);

- return sprintf(buf, "%u\n", acpi_dev->request_offline?1:0);
+ return sprintf(buf, "%u\n", acpi_dev->eject.request_offline?1:0);
}

static ssize_t request_offline_store(struct device *dev,
@@ -524,10 +524,10 @@ static ssize_t request_offline_store(struct device *dev,

switch (buf[0]) {
case '0':
- acpi_dev->request_offline = false;
+ acpi_dev->eject.request_offline = false;
break;
case '1':
- acpi_dev->request_offline = true;
+ acpi_dev->eject.request_offline = true;
break;
default:
return -EINVAL;
@@ -537,6 +537,74 @@ static ssize_t request_offline_store(struct device *dev,
}
static DEVICE_ATTR_RW(request_offline);

+static ssize_t auto_eject_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct acpi_device *acpi_dev = to_acpi_device(dev);
+
+ return sprintf(buf, "%u\n", acpi_dev->eject.poll_time);
+}
+
+static ssize_t auto_eject_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ struct acpi_device *acpi_dev = to_acpi_device(dev);
+ unsigned int time_interval;
+
+ if (!count)
+ return -EINVAL;
+
+ if (sscanf(buf, "%u\n", &time_interval) == 1)
+ acpi_dev->eject.poll_time = time_interval;
+
+ return count;
+}
+static DEVICE_ATTR_RW(auto_eject);
+
+static ssize_t
+cancel_eject_store(struct device *d, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct acpi_device *acpi_device = to_acpi_device(d);
+ acpi_object_type not_used;
+ acpi_status status;
+
+ if (!count || buf[0] != '1')
+ return -EINVAL;
+
+ if ((!acpi_device->handler || !acpi_device->handler->hotplug.enabled)
+ && !acpi_device->driver)
+ return -ENODEV;
+
+ status = acpi_get_type(acpi_device->handle, &not_used);
+ if (ACPI_FAILURE(status) || !acpi_device->flags.ejectable)
+ return -ENODEV;
+
+ if (!acpi_device->eject.in_progress)
+ return count;
+
+ acpi_device->eject.cancel = true;
+
+ if (!acpi_device->eject.poll_time) {
+ get_device(&acpi_device->dev);
+
+ status = acpi_hotplug_schedule(acpi_device,
+ ACPI_OST_EC_OSPM_EJECT);
+ if (ACPI_SUCCESS(status))
+ return count;
+
+ put_device(&acpi_device->dev);
+
+ acpi_evaluate_ost(acpi_device->handle, ACPI_OST_EC_OSPM_EJECT,
+ ACPI_OST_SC_NON_SPECIFIC_FAILURE, NULL);
+
+ return status == AE_NO_MEMORY ? -ENOMEM : -EAGAIN;
+ }
+
+ return count;
+}
+static DEVICE_ATTR_WO(cancel_eject);
+
/**
* acpi_device_setup_files - Create sysfs attributes of an ACPI device.
* @dev: ACPI device object.
@@ -616,6 +684,17 @@ int acpi_device_setup_files(struct acpi_device *dev)
&dev_attr_request_offline);
if (result)
return result;
+
+ result = device_create_file(&dev->dev,
+ &dev_attr_auto_eject);
+ if (result)
+ return result;
+
+ result = device_create_file(&dev->dev,
+ &dev_attr_cancel_eject);
+ if (result)
+ return result;
+
}

if (dev->flags.power_manageable) {
@@ -662,6 +741,8 @@ void acpi_device_remove_files(struct acpi_device *dev)
if (acpi_has_method(dev->handle, "_EJ0")) {
device_remove_file(&dev->dev, &dev_attr_eject);
device_remove_file(&dev->dev, &dev_attr_request_offline);
+ device_remove_file(&dev->dev, &dev_attr_auto_eject);
+ device_remove_file(&dev->dev, &dev_attr_cancel_eject);
}

if (acpi_has_method(dev->handle, "_SUN"))
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index e387517d3354..45f4ce42a044 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -81,6 +81,8 @@ static inline void acpi_lpss_init(void) {}
void acpi_apd_init(void);

acpi_status acpi_hotplug_schedule(struct acpi_device *adev, u32 src);
+acpi_status acpi_hotplug_delayed_schedule(struct acpi_device *adev,
+ u32 src, unsigned long delay);
bool acpi_queue_hotplug_work(struct work_struct *work);
void acpi_device_hotplug(struct acpi_device *adev, u32 src);
bool acpi_scan_is_offline(struct acpi_device *adev, bool uevent);
diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 762c5d50b8fe..0716c5bbff12 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -1143,33 +1143,44 @@ void acpi_os_wait_events_complete(void)
EXPORT_SYMBOL(acpi_os_wait_events_complete);

struct acpi_hp_work {
- struct work_struct work;
+ struct delayed_work work;
struct acpi_device *adev;
u32 src;
};

static void acpi_hotplug_work_fn(struct work_struct *work)
{
- struct acpi_hp_work *hpw = container_of(work, struct acpi_hp_work, work);
+ struct delayed_work *delay_work;
+ struct acpi_hp_work *hpw;
+
+ delay_work = container_of(work, struct delayed_work, work);
+ hpw = container_of(delay_work, struct acpi_hp_work, work);
+
+ if (!hpw) {
+ pr_debug("Null object of ACPI hotplug work.\n");
+ return;
+ }

acpi_os_wait_events_complete();
acpi_device_hotplug(hpw->adev, hpw->src);
kfree(hpw);
}

-acpi_status acpi_hotplug_schedule(struct acpi_device *adev, u32 src)
+static acpi_status acpi_hotplug_schedule_work(struct acpi_device *adev,
+ u32 src, unsigned long delay)
{
struct acpi_hp_work *hpw;

ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
- "Scheduling hotplug event (%p, %u) for deferred execution.\n",
- adev, src));
+ "Scheduling hotplug event (%p, %u, %lu) for deferred execution.\n",
+ adev, src, delay));

hpw = kmalloc(sizeof(*hpw), GFP_KERNEL);
if (!hpw)
return AE_NO_MEMORY;

- INIT_WORK(&hpw->work, acpi_hotplug_work_fn);
+ INIT_DELAYED_WORK(&hpw->work, acpi_hotplug_work_fn);
+
hpw->adev = adev;
hpw->src = src;
/*
@@ -1178,13 +1189,25 @@ acpi_status acpi_hotplug_schedule(struct acpi_device *adev, u32 src)
* invoke flush_scheduled_work()/acpi_os_wait_events_complete() to flush
* these workqueues.
*/
- if (!queue_work(kacpi_hotplug_wq, &hpw->work)) {
+ if (!queue_delayed_work(kacpi_hotplug_wq, &hpw->work, delay)) {
kfree(hpw);
return AE_ERROR;
}
+
return AE_OK;
}

+acpi_status acpi_hotplug_schedule(struct acpi_device *adev, u32 src)
+{
+ return acpi_hotplug_schedule_work(adev, src, 0);
+}
+
+acpi_status acpi_hotplug_delayed_schedule(struct acpi_device *adev,
+ u32 src, unsigned long delay)
+{
+ return acpi_hotplug_schedule_work(adev, src, delay);
+}
+
bool acpi_queue_hotplug_work(struct work_struct *work)
{
return queue_work(kacpi_hotplug_wq, work);
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 1cb39c5360cf..b4678ed14eed 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -169,7 +169,7 @@ static acpi_status acpi_bus_offline(acpi_handle handle, u32 lvl, void *data,
}

/* Don't offline directly but need to notify userland first */
- if (device->request_offline) {
+ if (device->eject.request_offline) {
if (pn->dev->offline)
ret = 0;
else
@@ -209,7 +209,7 @@ static acpi_status acpi_bus_online(acpi_handle handle, u32 lvl, void *data,

list_for_each_entry(pn, &device->physical_node_list, node)
if (pn->put_online) {
- if (device->request_offline)
+ if (device->eject.request_offline)
kobject_uevent_env(&pn->dev->kobj,
KOBJ_CHANGE, envp);
else
@@ -269,6 +269,41 @@ static int acpi_scan_try_to_offline(struct acpi_device *device)
return 0;
}

+static void acpi_scan_cancel_eject(struct acpi_device *device)
+{
+ acpi_handle handle = device->handle;
+
+ /* Get all nodes online again if necessary */
+ acpi_bus_online(handle, 0, NULL, NULL);
+ acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
+ acpi_bus_online, NULL, NULL, NULL);
+
+ device->eject.in_progress = false;
+ device->eject.cancel = false;
+}
+
+static inline void acpi_set_eject_status(struct acpi_device *device)
+{
+ unsigned long delay;
+ acpi_status status;
+
+ device->eject.in_progress = true;
+
+ if (!device->eject.poll_time)
+ return;
+
+ delay = device->eject.poll_time * HZ;
+
+ get_device(&device->dev);
+ status = acpi_hotplug_delayed_schedule(device,
+ ACPI_OST_EC_OSPM_EJECT, delay);
+
+ if (ACPI_FAILURE(status)) {
+ pr_err("Failed to schedule a delayed work\n");
+ put_device(&device->dev);
+ }
+}
+
static int acpi_scan_hot_remove(struct acpi_device *device)
{
acpi_handle handle = device->handle;
@@ -277,8 +312,13 @@ static int acpi_scan_hot_remove(struct acpi_device *device)
bool notify_single = false;
int error;

+ if (device->eject.request_offline && device->eject.cancel) {
+ acpi_scan_cancel_eject(device);
+ return -EBUSY;
+ }
+
if (device->handler && device->handler->hotplug.demand_offline)
- if (!device->request_offline)
+ if (!device->eject.request_offline)
notify_single = true;

if (!acpi_scan_is_offline(device, notify_single)) {
@@ -289,10 +329,15 @@ static int acpi_scan_hot_remove(struct acpi_device *device)
if (error)
return error;

- if (device->request_offline)
+ if (device->eject.request_offline) {
+ acpi_set_eject_status(device);
return -EBUSY;
+ }
}

+ device->eject.in_progress = false;
+ device->eject.cancel = false;
+
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Hot-removing device %s...\n", dev_name(&device->dev)));

diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 7a29ea0a7d0e..1fb72e399e0d 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -346,6 +346,13 @@ struct acpi_device_data {

struct acpi_gpio_mapping;

+struct acpi_eject_status {
+ bool request_offline;
+ bool in_progress;
+ bool cancel;
+ unsigned int poll_time; /* unit: second */
+};
+
/* Device */
struct acpi_device {
int device_type;
@@ -375,7 +382,7 @@ struct acpi_device {
struct list_head physical_node_list;
struct mutex physical_node_lock;
void (*remove)(struct acpi_device *);
- bool request_offline;
+ struct acpi_eject_status eject;
};

/* Non-device subnode */
--
2.24.0