ACPI / hotplug: Use device offline/online for graceful hot-removal
Modify the generic ACPI hotplug code to be able to check if devices
scheduled for hot-removal may be gracefully removed from the system
using the device offline/online mechanism introduced previously.
Namely, make acpi_scan_hot_remove() handling device hot-removal call
device_offline() for all physical companions of the ACPI device nodes
involved in the operation and check the results. If any of the
device_offline() calls fails, the function will not progress to the
removal phase (which cannot be aborted), unless its (new) force
argument is set (in case of a failing offline it will put the devices
offlined by it back online).
In support of 'forced' device hot-removal, add a new sysfs attribute
'force_remove' that will reside under /sys/firmware/acpi/hotplug/.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
diff --git a/drivers/acpi/sysfs.c b/drivers/acpi/sysfs.c
index fcae5fa..5c5d162 100644
--- a/drivers/acpi/sysfs.c
+++ b/drivers/acpi/sysfs.c
@@ -780,6 +780,33 @@
pr_err(PREFIX "Unable to add hotplug profile '%s'\n", name);
}
+static ssize_t force_remove_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%d\n", !!acpi_force_hot_remove);
+}
+
+static ssize_t force_remove_store(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ const char *buf, size_t size)
+{
+ bool val;
+ int ret;
+
+ ret = strtobool(buf, &val);
+ if (ret < 0)
+ return ret;
+
+ lock_device_hotplug();
+ acpi_force_hot_remove = val;
+ unlock_device_hotplug();
+ return size;
+}
+
+static const struct kobj_attribute force_remove_attr =
+ __ATTR(force_remove, S_IRUGO | S_IWUSR, force_remove_show,
+ force_remove_store);
+
int __init acpi_sysfs_init(void)
{
int result;
@@ -789,6 +816,10 @@
return result;
hotplug_kobj = kobject_create_and_add("hotplug", acpi_kobj);
+ result = sysfs_create_file(hotplug_kobj, &force_remove_attr.attr);
+ if (result)
+ return result;
+
result = sysfs_create_file(acpi_kobj, &pm_profile_attr.attr);
return result;
}