From 683058e315f00a216fd6c79df4f63bc9945ca434 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Fri, 3 May 2013 00:26:16 +0200 Subject: 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 Reviewed-by: Toshi Kani --- drivers/acpi/sysfs.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'drivers/acpi/sysfs.c') 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 @@ void acpi_sysfs_add_hotplug_profile(struct acpi_hotplug_profile *hotplug, 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 @@ int __init acpi_sysfs_init(void) 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; } -- cgit v1.1