[PATCH 0/3] ACPI: New eject flow to remove devices cautiously

[PATCH 0/3] ACPI: New eject flow to remove devices cautiously

[Chester Lin]

Currently there are two ways to handle ACPI device ejection. When an eject
event happens on a container, the kernel just sends KOBJ_CHANGE to
userland and userland should handle offline operation. For other device
types, acpi_scan_try_to_offline() is called and it tries to put target
device(s) offline and then removes all nodes once they are all offline.

However we found that sometimes applications could intensively access
resources on ejectable devices therefore they could have risk if ejection
suddenly happens and removes devices without any notification. In stead
of executing the offline callbakcs directly, we want to introduce a new
approach, which sends change events to notify all target nodes beforehand
and hands over offline handling to userland so that userland can have a
chance to schedule an offline task based on current workload. The online
function to recover from failure is also changed, it follows the same
approach to send change events rather than putting devices online directly
, which means userland will also need to take care of online handling.

To ensure that eject function can work properly since normal users might
not have their own offline/online handling, we will submit a generic udev
rule to systemd upstream as default in order to deal with change events
and take [offline/online] action accordingly. But the Hot-Removing part
still remains so the hotplug function can run to it once target nodes are
all offline.

To easily monitor eject status and start over an eject process, there's a
status trace mechanism in this eject flow, which helps to count current
online devices under the ejectable target, and it can reschedule an eject
event when all nodes within the device tree have been put offline.

Chester Lin (3):
  ACPI / hotplug: Send change events for offline/online requests when
    eject is triggered
  ACPI / hotplug: Eject status trace and auto-remove approach
  ACPI / device_sysfs: Add eject show attr to monitor eject status

 drivers/acpi/container.c    |   2 +-
 drivers/acpi/device_sysfs.c |  20 ++-
 drivers/acpi/glue.c         |  81 ++++++++++
 drivers/acpi/internal.h     |  31 +++-
 drivers/acpi/scan.c         | 298 ++++++++++++++++++++++++++----------
 drivers/base/core.c         |   2 +
 include/acpi/acpi_bus.h     |   3 +-
 7 files changed, 356 insertions(+), 81 deletions(-)

-- 
2.20.1

[PATCH 1/3] ACPI / hotplug: Send change events for offline/online requests when eject is triggered

[Chester Lin]

Here we change offline/online handling in device hotplug by sending change
events to userland as notification so that userland can have control and
determine when will be a good time to put them offline/online based on
current workload. In this approach the real offline/online opertions are
handed over to userland so that userland can have more time to prepare
before any device change actually happens.

All child devices under the ejection target are traversed and notified
hierarchically based on ACPI namespace in ascending order when an eject
event happens.

Signed-off-by: Chester Lin <clin@suse.com>
---
 drivers/acpi/container.c |   2 +-
 drivers/acpi/internal.h  |   2 +-
 drivers/acpi/scan.c      | 140 +++++++++++++++++----------------------
 include/acpi/acpi_bus.h  |   2 +-
 4 files changed, 65 insertions(+), 81 deletions(-)

diff --git a/drivers/acpi/container.c b/drivers/acpi/container.c
index 12c240903c18..f8c7768b4c8e 100644
--- a/drivers/acpi/container.c
+++ b/drivers/acpi/container.c
@@ -46,7 +46,7 @@ static int acpi_container_offline(struct container_dev *cdev)
 
 	/* Check all of the dependent devices' physical companions. */
 	list_for_each_entry(child, &adev->children, node)
-		if (!acpi_scan_is_offline(child, false))
+		if (!acpi_scan_is_offline(child))
 			return -EBUSY;
 
 	return 0;
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 6eaf06db7752..47014776fecb 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -92,7 +92,7 @@ void acpi_apd_init(void);
 acpi_status acpi_hotplug_schedule(struct acpi_device *adev, u32 src);
 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);
+bool acpi_scan_is_offline(struct acpi_device *adev);
 
 acpi_status acpi_sysfs_table_handler(u32 event, void *table, void *context);
 void acpi_scan_table_handler(u32 event, void *table, void *context);
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 0e28270b0fd8..d7628146eb5f 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -113,11 +113,10 @@ int acpi_scan_add_handler_with_hotplug(struct acpi_scan_handler *handler,
 	return 0;
 }
 
-bool acpi_scan_is_offline(struct acpi_device *adev, bool uevent)
+bool acpi_scan_is_offline(struct acpi_device *adev)
 {
 	struct acpi_device_physical_node *pn;
 	bool offline = true;
-	char *envp[] = { "EVENT=offline", NULL };
 
 	/*
 	 * acpi_container_offline() calls this for all of the container's
@@ -127,9 +126,6 @@ bool acpi_scan_is_offline(struct acpi_device *adev, bool uevent)
 
 	list_for_each_entry(pn, &adev->physical_node_list, node)
 		if (device_supports_offline(pn->dev) && !pn->dev->offline) {
-			if (uevent)
-				kobject_uevent_env(&pn->dev->kobj, KOBJ_CHANGE, envp);
-
 			offline = false;
 			break;
 		}
@@ -138,13 +134,12 @@ bool acpi_scan_is_offline(struct acpi_device *adev, bool uevent)
 	return offline;
 }
 
-static acpi_status acpi_bus_offline(acpi_handle handle, u32 lvl, void *data,
-				    void **ret_p)
+static acpi_status acpi_bus_offline_notify(acpi_handle handle, u32 lvl,
+					void *data, void **ret_p)
 {
 	struct acpi_device *device = NULL;
 	struct acpi_device_physical_node *pn;
-	bool second_pass = (bool)data;
-	acpi_status status = AE_OK;
+	char *envp[] = { "EVENT=offline", NULL };
 
 	if (acpi_bus_get_device(handle, &device))
 		return AE_OK;
@@ -155,100 +150,93 @@ static acpi_status acpi_bus_offline(acpi_handle handle, u32 lvl, void *data,
 	}
 
 	mutex_lock(&device->physical_node_lock);
-
 	list_for_each_entry(pn, &device->physical_node_list, node) {
-		int ret;
-
-		if (second_pass) {
-			/* Skip devices offlined by the first pass. */
-			if (pn->put_online)
-				continue;
-		} else {
-			pn->put_online = false;
-		}
-		ret = device_offline(pn->dev);
-		if (ret >= 0) {
-			pn->put_online = !ret;
-		} else {
-			*ret_p = pn->dev;
-			if (second_pass) {
-				status = AE_ERROR;
-				break;
-			}
+		if (device_supports_offline(pn->dev) && !(pn->dev->offline)) {
+			kobject_uevent_env(&pn->dev->kobj, KOBJ_CHANGE, envp);
+			pn->changed_offline = true;
 		}
 	}
-
 	mutex_unlock(&device->physical_node_lock);
 
-	return status;
+	return AE_OK;
 }
 
-static acpi_status acpi_bus_online(acpi_handle handle, u32 lvl, void *data,
-				   void **ret_p)
+static acpi_status acpi_bus_online_notify(acpi_handle handle, u32 lvl,
+						void *data, void **ret_p)
 {
 	struct acpi_device *device = NULL;
 	struct acpi_device_physical_node *pn;
+	char *envp[] = { "EVENT=online", NULL };
 
 	if (acpi_bus_get_device(handle, &device))
 		return AE_OK;
 
 	mutex_lock(&device->physical_node_lock);
 
-	list_for_each_entry(pn, &device->physical_node_list, node)
-		if (pn->put_online) {
-			device_online(pn->dev);
-			pn->put_online = false;
+	list_for_each_entry(pn, &device->physical_node_list, node) {
+		if (pn->changed_offline) {
+			kobject_uevent_env(&pn->dev->kobj, KOBJ_CHANGE, envp);
+			pn->changed_offline = false;
 		}
+	}
 
 	mutex_unlock(&device->physical_node_lock);
-
 	return AE_OK;
 }
 
-static int acpi_scan_try_to_offline(struct acpi_device *device)
+static void acpi_scan_notify_online(struct acpi_device *device)
+{
+	acpi_handle handle = device->handle;
+
+	acpi_bus_online_notify(handle, 0, NULL, NULL);
+	acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
+				acpi_bus_online_notify, NULL, NULL, NULL);
+}
+
+static int acpi_scan_notify_offline(struct acpi_device *device)
 {
 	acpi_handle handle = device->handle;
 	struct device *errdev = NULL;
 	acpi_status status;
 
-	/*
-	 * Carry out two passes here and ignore errors in the first pass,
-	 * because if the devices in question are memory blocks and
-	 * CONFIG_MEMCG is set, one of the blocks may hold data structures
-	 * that the other blocks depend on, but it is not known in advance which
-	 * block holds them.
-	 *
-	 * If the first pass is successful, the second one isn't needed, though.
-	 */
 	status = acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
-				     NULL, acpi_bus_offline, (void *)false,
-				     (void **)&errdev);
-	if (status == AE_SUPPORT) {
+			NULL, acpi_bus_offline_notify,
+			NULL, (void **)&errdev);
+	if (errdev)
+		goto notify_error;
+
+	status = acpi_bus_offline_notify(handle, 0, NULL,
+				(void **)&errdev);
+
+	if (errdev)
+		goto notify_error;
+
+	return 0;
+
+notify_error:
+	acpi_scan_notify_online(device);
+
+	switch (status) {
+	case AE_SUPPORT:
 		dev_warn(errdev, "Offline disabled.\n");
-		acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
-				    acpi_bus_online, NULL, NULL, NULL);
 		return -EPERM;
+	default:
+		dev_warn(errdev, "Offline failed. (status:%#x)\n", status);
+		return -EBUSY;
 	}
-	acpi_bus_offline(handle, 0, (void *)false, (void **)&errdev);
-	if (errdev) {
-		errdev = NULL;
-		acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
-				    NULL, acpi_bus_offline, (void *)true,
-				    (void **)&errdev);
-		if (!errdev)
-			acpi_bus_offline(handle, 0, (void *)true,
-					 (void **)&errdev);
-
-		if (errdev) {
-			dev_warn(errdev, "Offline failed.\n");
-			acpi_bus_online(handle, 0, NULL, NULL);
-			acpi_walk_namespace(ACPI_TYPE_ANY, handle,
-					    ACPI_UINT32_MAX, acpi_bus_online,
-					    NULL, NULL, NULL);
+}
+
+static int acpi_scan_offline_check(struct acpi_device *device)
+{
+	int ret = 0;
+	/* Send offline request to userland if the container is not offline */
+	if (!acpi_scan_is_offline(device)) {
+		ret = acpi_scan_notify_offline(device);
+		if (!ret)
 			return -EBUSY;
-		}
 	}
-	return 0;
+
+	return ret;
 }
 
 static int acpi_scan_hot_remove(struct acpi_device *device)
@@ -256,15 +244,11 @@ static int acpi_scan_hot_remove(struct acpi_device *device)
 	acpi_handle handle = device->handle;
 	unsigned long long sta;
 	acpi_status status;
+	int ret;
 
-	if (device->handler && device->handler->hotplug.demand_offline) {
-		if (!acpi_scan_is_offline(device, true))
-			return -EBUSY;
-	} else {
-		int error = acpi_scan_try_to_offline(device);
-		if (error)
-			return error;
-	}
+	ret = acpi_scan_offline_check(device);
+	if (ret)
+		return ret;
 
 	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 52d4375bde9d..2ad8262f2a47 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -343,7 +343,7 @@ struct acpi_device_physical_node {
 	unsigned int node_id;
 	struct list_head node;
 	struct device *dev;
-	bool put_online:1;
+	bool changed_offline:1;
 };
 
 struct acpi_device_properties {
-- 
2.20.1

[PATCH 2/3] ACPI / hotplug: Eject status trace and auto-remove approach

[Chester Lin]

This is an eject-status trace mechanism which helps to count current online
devices under the ejection target, and it can automatically reschedules an
eject event when all related devices are offline. The number of online
nodes can be updated when any node has been put offline successfully.
Any online event within the whole device tree during ejection will stop the
whole process and devices who have been put offline will need be online
again as recovery.

Signed-off-by: Chester Lin <clin@suse.com>
---
 drivers/acpi/glue.c     |  81 +++++++++++++++++++++++
 drivers/acpi/internal.h |  28 ++++++++
 drivers/acpi/scan.c     | 139 +++++++++++++++++++++++++++++++++++++++-
 drivers/base/core.c     |   2 +
 include/acpi/acpi_bus.h |   1 +
 5 files changed, 248 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c
index edd10b3c7ec8..50745b12ae84 100644
--- a/drivers/acpi/glue.c
+++ b/drivers/acpi/glue.c
@@ -361,6 +361,81 @@ static int acpi_device_notify_remove(struct device *dev)
 	return 0;
 }
 
+static void acpi_device_eject_tracer(struct device *dev,
+				enum kobject_action action)
+{
+	struct acpi_device *adev = ACPI_COMPANION(dev);
+	struct acpi_device *adev_root = NULL;
+	struct eject_data *eject_node = NULL;
+	struct eject_data *eject_root = NULL;
+
+	if (!adev || !adev->eject_stat)
+		return;
+
+	acpi_scan_lock_acquire();
+
+	eject_node = (struct eject_data *)adev->eject_stat;
+
+	if (eject_node->base.root_handle)
+		adev_root =
+		    acpi_bus_get_acpi_device(eject_node->base.root_handle);
+
+	if (adev_root)
+		eject_root = (struct eject_data *)adev_root->eject_stat;
+
+	if (action == KOBJ_OFFLINE) {
+		/*
+		 * If the offline device is child, update its eject_root's
+		 * number of online nodes.
+		 */
+		if (eject_root) {
+			if (eject_root->online_nodes)
+				eject_root->online_nodes--;
+
+			if (eject_root->online_nodes <=
+			    adev_root->physical_node_count)
+				acpi_eject_retry(adev_root);
+
+			goto tracer_end;
+		}
+		/*
+		 * Adjust number of online nodes when any physical node under
+		 * eject_root is offline. Trigger acpi_eject_try() once all
+		 * nodes are offline.
+		 */
+		if (eject_node->online_nodes)
+			eject_node->online_nodes--;
+
+		if (!eject_node->online_nodes)
+			acpi_eject_retry(adev);
+
+	} else if (action == KOBJ_ONLINE) {
+		/* !eject_root means now eject_node is root */
+		if (!eject_root)
+			eject_root = eject_node;
+
+		if (eject_root->status == ACPI_EJECT_STATUS_GOING_OFFLINE) {
+			eject_root->status = ACPI_EJECT_STATUS_FAIL;
+			acpi_eject_retry(adev_root);
+		}
+	}
+tracer_end:
+	if (adev_root)
+		acpi_bus_put_acpi_device(adev_root);
+
+	acpi_scan_lock_release();
+}
+
+static inline void acpi_device_check_eject_status(struct device *dev)
+{
+	acpi_device_eject_tracer(dev, KOBJ_OFFLINE);
+}
+
+static inline void acpi_device_check_eject_recover(struct device *dev)
+{
+	acpi_device_eject_tracer(dev, KOBJ_ONLINE);
+}
+
 int acpi_platform_notify(struct device *dev, enum kobject_action action)
 {
 	switch (action) {
@@ -370,6 +445,12 @@ int acpi_platform_notify(struct device *dev, enum kobject_action action)
 	case KOBJ_REMOVE:
 		acpi_device_notify_remove(dev);
 		break;
+	case KOBJ_OFFLINE:
+		acpi_device_check_eject_status(dev);
+		break;
+	case KOBJ_ONLINE:
+		acpi_device_check_eject_recover(dev);
+		break;
 	default:
 		break;
 	}
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 47014776fecb..0dcec4243b23 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -266,4 +266,32 @@ void acpi_init_lpit(void);
 static inline void acpi_init_lpit(void) { }
 #endif
 
+/* --------------------------------------------------------------------------
+ *				Eject Status
+ * --------------------------------------------------------------------------
+ */
+enum acpi_eject_status {
+	ACPI_EJECT_STATUS_NONE = 0,
+	ACPI_EJECT_STATUS_GOING_OFFLINE,
+	ACPI_EJECT_STATUS_FAIL
+};
+
+enum acpi_eject_node_type {
+	ACPI_EJECT_CHILD_NODE = 0,
+	ACPI_EJECT_ROOT_NODE
+};
+
+struct eject_data_base {
+	enum acpi_eject_node_type type;
+	acpi_handle root_handle;
+};
+
+struct eject_data {
+	struct eject_data_base base;
+	enum acpi_eject_status status;
+	u32 online_nodes;
+};
+
+void acpi_eject_retry(struct acpi_device *adev);
+
 #endif /* _ACPI_INTERNAL_H_ */
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index d7628146eb5f..c60110db1cd6 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -134,11 +134,110 @@ bool acpi_scan_is_offline(struct acpi_device *adev)
 	return offline;
 }
 
+void acpi_eject_retry(struct acpi_device *adev)
+{
+	acpi_status status;
+
+	get_device(&adev->dev);
+
+	status = acpi_hotplug_schedule(adev, ACPI_OST_EC_OSPM_EJECT);
+	if (ACPI_FAILURE(status)) {
+		pr_debug("Failed to reschedule an eject event\n");
+		put_device(&adev->dev);
+		acpi_evaluate_ost(adev->handle, ACPI_OST_EC_OSPM_EJECT,
+				ACPI_OST_SC_NON_SPECIFIC_FAILURE, NULL);
+		return;
+	}
+	pr_debug("Rescheduled an eject event\n");
+}
+
+static acpi_status acpi_init_eject_stat(struct acpi_device *adev,
+					enum acpi_eject_node_type type)
+{
+	struct eject_data *eject_node = (struct eject_data *) adev->eject_stat;
+
+	if (!eject_node) {
+		eject_node = kzalloc(sizeof(*eject_node), GFP_KERNEL);
+		if (!eject_node)
+			return AE_NO_MEMORY;
+		adev->eject_stat = eject_node;
+	}
+
+	eject_node->base.type = type;
+
+	if (type == ACPI_EJECT_CHILD_NODE)
+		return AE_OK;
+
+	/* Initialization of eject root node */
+	eject_node->status = ACPI_EJECT_STATUS_GOING_OFFLINE;
+	eject_node->online_nodes = 0;
+
+	return AE_OK;
+}
+
+static void acpi_enable_eject_stat(struct acpi_device *adev,
+				struct acpi_device *root_adev, u32 online_nodes)
+{
+	struct eject_data *eject_node = NULL;
+	struct eject_data *eject_root = NULL;
+
+	if (adev)
+		eject_node = (struct eject_data *)adev->eject_stat;
+	if (root_adev)
+		eject_root = (struct eject_data *)root_adev->eject_stat;
+
+	if (eject_node) {
+		if (eject_node != eject_root)
+			eject_node->base.root_handle = root_adev->handle;
+		else
+			eject_node->base.root_handle = 0;
+	}
+
+	/* Update online_nodes of root device */
+	if (eject_root) {
+		eject_root->online_nodes += online_nodes;
+		pr_debug("Current online nodes:%u\n",
+			eject_root->online_nodes);
+	}
+}
+
+static void acpi_free_eject_stat(struct acpi_device *adev)
+{
+	kfree(adev->eject_stat);
+	adev->eject_stat = NULL;
+}
+
+static acpi_status acpi_bus_offline_prepare(acpi_handle handle, u32 lvl,
+					void *data, void **ret_p)
+{
+	struct acpi_device *device = NULL;
+	struct eject_data_base *eject_obj = (struct eject_data_base *)data;
+	acpi_status status = AE_OK;
+
+	if (acpi_bus_get_device(handle, &device))
+		return AE_OK;
+
+	if (device->handler && !device->handler->hotplug.enabled) {
+		*ret_p = &device->dev;
+		return AE_SUPPORT;
+	}
+
+	status = acpi_init_eject_stat(device, eject_obj->type);
+	if (ACPI_FAILURE(status))
+		*ret_p = &device->dev;
+
+	return status;
+}
+
+
 static acpi_status acpi_bus_offline_notify(acpi_handle handle, u32 lvl,
 					void *data, void **ret_p)
 {
 	struct acpi_device *device = NULL;
+	struct acpi_device *root_device = NULL;
 	struct acpi_device_physical_node *pn;
+	struct eject_data_base *eject_obj = (struct eject_data_base *)data;
+	u32 online_nodes = 0;
 	char *envp[] = { "EVENT=offline", NULL };
 
 	if (acpi_bus_get_device(handle, &device))
@@ -149,13 +248,22 @@ static acpi_status acpi_bus_offline_notify(acpi_handle handle, u32 lvl,
 		return AE_SUPPORT;
 	}
 
+	if (eject_obj->root_handle == device->handle) {
+		root_device = device;
+	} else if (acpi_bus_get_device(eject_obj->root_handle, &root_device)) {
+		*ret_p = &device->dev;
+		return AE_NULL_OBJECT;
+	}
+
 	mutex_lock(&device->physical_node_lock);
 	list_for_each_entry(pn, &device->physical_node_list, node) {
 		if (device_supports_offline(pn->dev) && !(pn->dev->offline)) {
 			kobject_uevent_env(&pn->dev->kobj, KOBJ_CHANGE, envp);
+			online_nodes++;
 			pn->changed_offline = true;
 		}
 	}
+	acpi_enable_eject_stat(device, root_device, online_nodes);
 	mutex_unlock(&device->physical_node_lock);
 
 	return AE_OK;
@@ -171,6 +279,8 @@ static acpi_status acpi_bus_online_notify(acpi_handle handle, u32 lvl,
 	if (acpi_bus_get_device(handle, &device))
 		return AE_OK;
 
+	acpi_free_eject_stat(device);
+
 	mutex_lock(&device->physical_node_lock);
 
 	list_for_each_entry(pn, &device->physical_node_list, node) {
@@ -197,15 +307,23 @@ static int acpi_scan_notify_offline(struct acpi_device *device)
 {
 	acpi_handle handle = device->handle;
 	struct device *errdev = NULL;
+	struct eject_data_base base_data = {ACPI_EJECT_ROOT_NODE, handle};
 	acpi_status status;
 
+	status = acpi_bus_offline_prepare(handle, 0, (void *)&base_data,
+					(void **)&errdev);
+	if (errdev)
+		goto notify_error;
+
+	base_data.type = ACPI_EJECT_CHILD_NODE;
 	status = acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
-			NULL, acpi_bus_offline_notify,
-			NULL, (void **)&errdev);
+			acpi_bus_offline_prepare, acpi_bus_offline_notify,
+			(void *)&base_data, (void **)&errdev);
 	if (errdev)
 		goto notify_error;
 
-	status = acpi_bus_offline_notify(handle, 0, NULL,
+	base_data.type = ACPI_EJECT_ROOT_NODE;
+	status = acpi_bus_offline_notify(handle, 0, (void *)&base_data,
 				(void **)&errdev);
 
 	if (errdev)
@@ -217,6 +335,10 @@ static int acpi_scan_notify_offline(struct acpi_device *device)
 	acpi_scan_notify_online(device);
 
 	switch (status) {
+	case AE_NO_MEMORY:
+		return -ENOMEM;
+	case AE_NULL_OBJECT:
+		return -EINVAL;
 	case AE_SUPPORT:
 		dev_warn(errdev, "Offline disabled.\n");
 		return -EPERM;
@@ -229,6 +351,15 @@ static int acpi_scan_notify_offline(struct acpi_device *device)
 static int acpi_scan_offline_check(struct acpi_device *device)
 {
 	int ret = 0;
+	struct eject_data *eject_obj = (struct eject_data *) device->eject_stat;
+
+	/* Send recovery events to userland if any failure occur */
+	if (eject_obj && eject_obj->status == ACPI_EJECT_STATUS_FAIL) {
+		dev_warn(&device->dev, "Eject failed. Recover bus status\n");
+		acpi_scan_notify_online(device);
+		return -EAGAIN;
+	}
+
 	/* Send offline request to userland if the container is not offline */
 	if (!acpi_scan_is_offline(device)) {
 		ret = acpi_scan_notify_offline(device);
@@ -2060,6 +2191,8 @@ void acpi_bus_trim(struct acpi_device *adev)
 	list_for_each_entry_reverse(child, &adev->children, node)
 		acpi_bus_trim(child);
 
+	acpi_free_eject_stat(adev);
+
 	adev->flags.match_driver = false;
 	if (handler) {
 		if (handler->detach)
diff --git a/drivers/base/core.c b/drivers/base/core.c
index fd7511e04e62..aca6976ed19b 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -2542,6 +2542,7 @@ int device_offline(struct device *dev)
 			if (!ret) {
 				kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
 				dev->offline = true;
+				device_platform_notify(dev, KOBJ_OFFLINE);
 			}
 		}
 	}
@@ -2571,6 +2572,7 @@ int device_online(struct device *dev)
 			if (!ret) {
 				kobject_uevent(&dev->kobj, KOBJ_ONLINE);
 				dev->offline = false;
+				device_platform_notify(dev, KOBJ_ONLINE);
 			}
 		} else {
 			ret = 1;
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 2ad8262f2a47..f587bd1ca6ba 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -391,6 +391,7 @@ struct acpi_device {
 	struct list_head physical_node_list;
 	struct mutex physical_node_lock;
 	void (*remove)(struct acpi_device *);
+	void *eject_stat;
 };
 
 /* Non-device subnode */
-- 
2.20.1

[PATCH 3/3] ACPI / device_sysfs: Add eject show attr to monitor eject status

[Chester Lin]

An acpi_eject_show attribute for users to monitor current status because
sometimes it might take time to finish an ejection so we need to know
whether it is still in progress or not.

Signed-off-by: Chester Lin <clin@suse.com>
---
 drivers/acpi/device_sysfs.c | 20 +++++++++++++++++++-
 drivers/acpi/internal.h     |  1 +
 drivers/acpi/scan.c         | 27 +++++++++++++++++++++++++++
 3 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/device_sysfs.c b/drivers/acpi/device_sysfs.c
index 78c2653bf020..70b22eec6bbc 100644
--- a/drivers/acpi/device_sysfs.c
+++ b/drivers/acpi/device_sysfs.c
@@ -403,7 +403,25 @@ acpi_eject_store(struct device *d, struct device_attribute *attr,
 	return status == AE_NO_MEMORY ? -ENOMEM : -EAGAIN;
 }
 
-static DEVICE_ATTR(eject, 0200, NULL, acpi_eject_store);
+static ssize_t acpi_eject_show(struct device *d,
+				struct device_attribute *attr, char *buf)
+{
+	struct acpi_device *acpi_device = to_acpi_device(d);
+	acpi_object_type not_used;
+	acpi_status status;
+
+	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;
+
+	return sprintf(buf, "%s\n", acpi_eject_status_string(acpi_device));
+}
+
+static DEVICE_ATTR(eject, 0644, acpi_eject_show, acpi_eject_store);
 
 static ssize_t
 acpi_device_hid_show(struct device *dev, struct device_attribute *attr, char *buf)
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 0dcec4243b23..e7037d68c3d9 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -293,5 +293,6 @@ struct eject_data {
 };
 
 void acpi_eject_retry(struct acpi_device *adev);
+char *acpi_eject_status_string(struct acpi_device *adev);
 
 #endif /* _ACPI_INTERNAL_H_ */
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index c60110db1cd6..27c4c1148879 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -370,6 +370,33 @@ static int acpi_scan_offline_check(struct acpi_device *device)
 	return ret;
 }
 
+char *acpi_eject_status_string(struct acpi_device *adev)
+{
+	struct eject_data *eject_obj;
+	char *status_string = "none";
+
+	mutex_lock(&acpi_scan_lock);
+	eject_obj = (struct eject_data *) adev->eject_stat;
+
+	if (eject_obj) {
+		switch (eject_obj->status) {
+		case ACPI_EJECT_STATUS_NONE:
+			break;
+		case ACPI_EJECT_STATUS_GOING_OFFLINE:
+			status_string = "going offline";
+			break;
+		case ACPI_EJECT_STATUS_FAIL:
+			status_string = "failure";
+			break;
+		default:
+			status_string = "(unknown)";
+		}
+	}
+
+	mutex_unlock(&acpi_scan_lock);
+	return status_string;
+}
+
 static int acpi_scan_hot_remove(struct acpi_device *device)
 {
 	acpi_handle handle = device->handle;
-- 
2.20.1

Re: [PATCH 3/3] ACPI / device_sysfs: Add eject show attr to monitor eject status

[Greg KH]

On Fri, May 31, 2019 at 02:56:42PM +0800, Chester Lin wrote:
> An acpi_eject_show attribute for users to monitor current status because
> sometimes it might take time to finish an ejection so we need to know
> whether it is still in progress or not.
> 
> Signed-off-by: Chester Lin <clin@suse.com>
> ---
>  drivers/acpi/device_sysfs.c | 20 +++++++++++++++++++-
>  drivers/acpi/internal.h     |  1 +
>  drivers/acpi/scan.c         | 27 +++++++++++++++++++++++++++
>  3 files changed, 47 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/device_sysfs.c b/drivers/acpi/device_sysfs.c
> index 78c2653bf020..70b22eec6bbc 100644
> --- a/drivers/acpi/device_sysfs.c
> +++ b/drivers/acpi/device_sysfs.c
> @@ -403,7 +403,25 @@ acpi_eject_store(struct device *d, struct device_attribute *attr,
>  	return status == AE_NO_MEMORY ? -ENOMEM : -EAGAIN;
>  }
>  
> -static DEVICE_ATTR(eject, 0200, NULL, acpi_eject_store);
> +static ssize_t acpi_eject_show(struct device *d,
> +				struct device_attribute *attr, char *buf)
> +{
> +	struct acpi_device *acpi_device = to_acpi_device(d);
> +	acpi_object_type not_used;
> +	acpi_status status;
> +
> +	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;
> +
> +	return sprintf(buf, "%s\n", acpi_eject_status_string(acpi_device));
> +}
> +
> +static DEVICE_ATTR(eject, 0644, acpi_eject_show, acpi_eject_store);

DEVICE_ATTR_RW()?

And you need to document the new sysfs file in Documentation/ABI/

thanks,

greg k-h

Re: [PATCH 3/3] ACPI / device_sysfs: Add eject show attr to monitor eject status

[Chester Lin]

On Fri, May 31, 2019 at 06:38:59AM -0700, Greg KH wrote:
> On Fri, May 31, 2019 at 02:56:42PM +0800, Chester Lin wrote:
> > An acpi_eject_show attribute for users to monitor current status because
> > sometimes it might take time to finish an ejection so we need to know
> > whether it is still in progress or not.
> > 
> > Signed-off-by: Chester Lin <clin@suse.com>
> > ---
> >  drivers/acpi/device_sysfs.c | 20 +++++++++++++++++++-
> >  drivers/acpi/internal.h     |  1 +
> >  drivers/acpi/scan.c         | 27 +++++++++++++++++++++++++++
> >  3 files changed, 47 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/acpi/device_sysfs.c b/drivers/acpi/device_sysfs.c
> > index 78c2653bf020..70b22eec6bbc 100644
> > --- a/drivers/acpi/device_sysfs.c
> > +++ b/drivers/acpi/device_sysfs.c
> > @@ -403,7 +403,25 @@ acpi_eject_store(struct device *d, struct device_attribute *attr,
> >  	return status == AE_NO_MEMORY ? -ENOMEM : -EAGAIN;
> >  }
> >  
> > -static DEVICE_ATTR(eject, 0200, NULL, acpi_eject_store);
> > +static ssize_t acpi_eject_show(struct device *d,
> > +				struct device_attribute *attr, char *buf)
> > +{
> > +	struct acpi_device *acpi_device = to_acpi_device(d);
> > +	acpi_object_type not_used;
> > +	acpi_status status;
> > +
> > +	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;
> > +
> > +	return sprintf(buf, "%s\n", acpi_eject_status_string(acpi_device));
> > +}
> > +
> > +static DEVICE_ATTR(eject, 0644, acpi_eject_show, acpi_eject_store);
> 
> DEVICE_ATTR_RW()?
> 
> And you need to document the new sysfs file in Documentation/ABI/
> 
> thanks,
> 
> greg k-h
> 

Hi Greg,

Thank you for the reminder and I will fix these two in v2.

Regards,
Chester