Merge branch 'akpm' (patches from Andrew)

Merge yet more updates from Andrew Morton:

 - More MM work. 100ish more to go. Mike Rapoport's "mm: remove
   __ARCH_HAS_5LEVEL_HACK" series should fix the current ppc issue

 - Various other little subsystems

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (127 commits)
  lib/ubsan.c: fix gcc-10 warnings
  tools/testing/selftests/vm: remove duplicate headers
  selftests: vm: pkeys: fix multilib builds for x86
  selftests: vm: pkeys: use the correct page size on powerpc
  selftests/vm/pkeys: override access right definitions on powerpc
  selftests/vm/pkeys: test correct behaviour of pkey-0
  selftests/vm/pkeys: introduce a sub-page allocator
  selftests/vm/pkeys: detect write violation on a mapped access-denied-key page
  selftests/vm/pkeys: associate key on a mapped page and detect write violation
  selftests/vm/pkeys: associate key on a mapped page and detect access violation
  selftests/vm/pkeys: improve checks to determine pkey support
  selftests/vm/pkeys: fix assertion in test_pkey_alloc_exhaust()
  selftests/vm/pkeys: fix number of reserved powerpc pkeys
  selftests/vm/pkeys: introduce powerpc support
  selftests/vm/pkeys: introduce generic pkey abstractions
  selftests: vm: pkeys: use the correct huge page size
  selftests/vm/pkeys: fix alloc_random_pkey() to make it really random
  selftests/vm/pkeys: fix assertion in pkey_disable_set/clear()
  selftests/vm/pkeys: fix pkey_disable_clear()
  selftests: vm: pkeys: add helpers for pkey bits
  ...

1 files changed, 26 insertions, 2 deletions

diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
index 1e678bdf5aed..275aa5f87399 100644
--- a/drivers/dax/kmem.c
+++ b/drivers/dax/kmem.c
@@ -14,6 +14,11 @@
 #include "dax-private.h"
 #include "bus.h"
 
+/* Memory resource name used for add_memory_driver_managed(). */
+static const char *kmem_name;
+/* Set if any memory will remain added when the driver will be unloaded. */
+static bool any_hotremove_failed;
+
 int dev_dax_kmem_probe(struct device *dev)
 {
 	struct dev_dax *dev_dax = to_dev_dax(dev);
@@ -70,7 +75,12 @@ int dev_dax_kmem_probe(struct device *dev)
 	 */
 	new_res->flags = IORESOURCE_SYSTEM_RAM;
 
-	rc = add_memory(numa_node, new_res->start, resource_size(new_res));
+	/*
+	 * Ensure that future kexec'd kernels will not treat this as RAM
+	 * automatically.
+	 */
+	rc = add_memory_driver_managed(numa_node, new_res->start,
+				       resource_size(new_res), kmem_name);
 	if (rc) {
 		release_resource(new_res);
 		kfree(new_res);
@@ -100,6 +110,7 @@ static int dev_dax_kmem_remove(struct device *dev)
 	 */
 	rc = remove_memory(dev_dax->target_node, kmem_start, kmem_size);
 	if (rc) {
+		any_hotremove_failed = true;
 		dev_err(dev,
 			"DAX region %pR cannot be hotremoved until the next reboot\n",
 			res);
@@ -124,6 +135,7 @@ static int dev_dax_kmem_remove(struct device *dev)
 	 * permanently pinned as reserved by the unreleased
 	 * request_mem_region().
 	 */
+	any_hotremove_failed = true;
 	return 0;
 }
 #endif /* CONFIG_MEMORY_HOTREMOVE */
@@ -137,12 +149,24 @@ static struct dax_device_driver device_dax_kmem_driver = {
 
 static int __init dax_kmem_init(void)
 {
-	return dax_driver_register(&device_dax_kmem_driver);
+	int rc;
+
+	/* Resource name is permanently allocated if any hotremove fails. */
+	kmem_name = kstrdup_const("System RAM (kmem)", GFP_KERNEL);
+	if (!kmem_name)
+		return -ENOMEM;
+
+	rc = dax_driver_register(&device_dax_kmem_driver);
+	if (rc)
+		kfree_const(kmem_name);
+	return rc;
 }
 
 static void __exit dax_kmem_exit(void)
 {
 	dax_driver_unregister(&device_dax_kmem_driver);
+	if (!any_hotremove_failed)
+		kfree_const(kmem_name);
 }
 
 MODULE_AUTHOR("Intel Corporation");