5 files changed, 16 insertions, 29 deletions

diff --git a/Documentation/ABI/obsolete/sysfs-firmware-acpi b/Documentation/ABI/obsolete/sysfs-firmware-acpi
new file mode 100644
index 000000000000..6715a71bec3d
--- /dev/null
+++ b/Documentation/ABI/obsolete/sysfs-firmware-acpi
@@ -0,0 +1,8 @@
+What:           /sys/firmware/acpi/hotplug/force_remove
+Date:           Mar 2017
+Contact:        Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+Description:
+                Since the force_remove is inherently broken and dangerous to
+                use for some hotplugable resources like memory (because ignoring
+                the offline failure might lead to memory corruption and crashes)
+                enabling this knob is not safe and thus unsupported.
diff --git a/Documentation/ABI/testing/sysfs-firmware-acpi b/Documentation/ABI/testing/sysfs-firmware-acpi
index c7fc72d4495c..613f42a9d5cd 100644
--- a/Documentation/ABI/testing/sysfs-firmware-acpi
+++ b/Documentation/ABI/testing/sysfs-firmware-acpi
@@ -44,16 +44,6 @@ Description:
                 or 0 (unset).  Attempts to write any other values to it will
                 cause -EINVAL to be returned.
 
-What:           /sys/firmware/acpi/hotplug/force_remove
-Date:           May 2013
-Contact:        Rafael J. Wysocki <rafael.j.wysocki@intel.com>
-Description:
-                The number in this file (0 or 1) determines whether (1) or not
-                (0) the ACPI subsystem will allow devices to be hot-removed even
-                if they cannot be put offline gracefully (from the kernel's
-                viewpoint).  That number can be changed by writing a boolean
-                value to this file.
-
 What:           /sys/firmware/acpi/interrupts/
 Date:           February 2008
 Contact:        Len Brown <lenb@kernel.org>
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index f15900132912..66229ffa909b 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -65,8 +65,6 @@ static inline void acpi_cmos_rtc_init(void) {}
 #endif
 int acpi_rev_override_setup(char *str);
 
-extern bool acpi_force_hot_remove;
-
 void acpi_sysfs_add_hotplug_profile(struct acpi_hotplug_profile *hotplug,
                                     const char *name);
 int acpi_scan_add_handler_with_hotplug(struct acpi_scan_handler *handler,
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 192691880d55..e2080b6e54aa 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -30,12 +30,6 @@ extern struct acpi_device *acpi_root;
 
 #define INVALID_ACPI_HANDLE     ((acpi_handle)empty_zero_page)
 
-/*
- * If set, devices will be hot-removed even if they cannot be put offline
- * gracefully (from the kernel's standpoint).
- */
-bool acpi_force_hot_remove;
-
 static const char *dummy_hid = "device";
 
 static LIST_HEAD(acpi_dep_list);
@@ -170,9 +164,6 @@ static acpi_status acpi_bus_offline(acpi_handle handle, u32 lvl, void *data,
                         pn->put_online = false;
                 }
                 ret = device_offline(pn->dev);
-                if (acpi_force_hot_remove)
-                        continue;
-
                 if (ret >= 0) {
                         pn->put_online = !ret;
                 } else {
@@ -241,11 +232,11 @@ static int acpi_scan_try_to_offline(struct acpi_device *device)
                 acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
                                     NULL, acpi_bus_offline, (void *)true,
                                     (void **)&errdev);
-                if (!errdev || acpi_force_hot_remove)
+                if (!errdev)
                         acpi_bus_offline(handle, 0, (void *)true,
                                          (void **)&errdev);
 
-                if (errdev && !acpi_force_hot_remove) {
+                if (errdev) {
                         dev_warn(errdev, "Offline failed.\n");
                         acpi_bus_online(handle, 0, NULL, NULL);
                         acpi_walk_namespace(ACPI_TYPE_ANY, handle,
@@ -263,8 +254,7 @@ static int acpi_scan_hot_remove(struct acpi_device *device)
         unsigned long long sta;
         acpi_status status;
 
-        if (device->handler && device->handler->hotplug.demand_offline
-            && !acpi_force_hot_remove) {
+        if (device->handler && device->handler->hotplug.demand_offline) {
                 if (!acpi_scan_is_offline(device, true))
                         return -EBUSY;
         } else {
diff --git a/drivers/acpi/sysfs.c b/drivers/acpi/sysfs.c
index cf05ae973381..1b5ee1e0e5a3 100644
--- a/drivers/acpi/sysfs.c
+++ b/drivers/acpi/sysfs.c
@@ -921,7 +921,7 @@ void acpi_sysfs_add_hotplug_profile(struct acpi_hotplug_profile *hotplug,
 static ssize_t force_remove_show(struct kobject *kobj,
                                  struct kobj_attribute *attr, char *buf)
 {
-        return sprintf(buf, "%d\n", !!acpi_force_hot_remove);
+        return sprintf(buf, "%d\n", 0);
 }
 
 static ssize_t force_remove_store(struct kobject *kobj,
@@ -935,9 +935,10 @@ static ssize_t force_remove_store(struct kobject *kobj,
         if (ret < 0)
                 return ret;
 
-        lock_device_hotplug();
-        acpi_force_hot_remove = val;
-        unlock_device_hotplug();
+        if (val) {
+                pr_err("Enabling force_remove is not supported anymore. Please report to linux-acpi@vger.kernel.org if you depend on this functionality\n");
+                return -EINVAL;
+        }
         return size;
 }