Merge branch 'akpm' (patches from Andrew)

Merge misc fixes from Andrew Morton:
 "17 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  drivers/acpi/scan.c: document why we don't need the device_hotplug_lock
  memremap: move from kernel/ to mm/
  lib/test_meminit.c: use GFP_ATOMIC in RCU critical section
  asm-generic: fix -Wtype-limits compiler warnings
  cgroup: kselftest: relax fs_spec checks
  mm/memory_hotplug.c: remove unneeded return for void function
  mm/migrate.c: initialize pud_entry in migrate_vma()
  coredump: split pipe command whitespace before expanding template
  page flags: prioritize kasan bits over last-cpuid
  ubsan: build ubsan.c more conservatively
  kasan: remove clang version check for KASAN_STACK
  mm: compaction: avoid 100% CPU usage during compaction when a task is killed
  mm: migrate: fix reference check race between __find_get_block() and migration
  mm: vmscan: check if mem cgroup is disabled or not before calling memcg slab shrinker
  ocfs2: remove set but not used variable 'last_hash'
  Revert "kmemleak: allow to coexist with fault injection"
  kernel/signal.c: fix a kernel-doc markup

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 0e28270b0fd8..aad6be5c0af0 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -2204,6 +2204,12 @@ int __init acpi_scan_init(void)
 	acpi_gpe_apply_masked_gpes();
 	acpi_update_all_gpes();
 
+	/*
+	 * Although we call __add_memory() that is documented to require the
+	 * device_hotplug_lock, it is not necessary here because this is an
+	 * early code when userspace or any other code path cannot trigger
+	 * hotplug/hotunplug operations.
+	 */
 	mutex_lock(&acpi_scan_lock);
 	/*
 	 * Enumerate devices in the ACPI namespace.