Merge branch 'akpm' (patches from Andrew)

Merge some more updates from Andrew Morton:

 - various hotfixes and minor things

 - hch's use_mm/unuse_mm clearnups

Subsystems affected by this patch series: mm/hugetlb, scripts, kcov,
lib, nilfs, checkpatch, lib, mm/debug, ocfs2, lib, misc.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  kernel: set USER_DS in kthread_use_mm
  kernel: better document the use_mm/unuse_mm API contract
  kernel: move use_mm/unuse_mm to kthread.c
  kernel: move use_mm/unuse_mm to kthread.c
  stacktrace: cleanup inconsistent variable type
  lib: test get_count_order/long in test_bitops.c
  mm: add comments on pglist_data zones
  ocfs2: fix spelling mistake and grammar
  mm/debug_vm_pgtable: fix kernel crash by checking for THP support
  lib: fix bitmap_parse() on 64-bit big endian archs
  checkpatch: correct check for kernel parameters doc
  nilfs2: fix null pointer dereference at nilfs_segctor_do_construct()
  lib/lz4/lz4_decompress.c: document deliberate use of `&'
  kcov: check kcov_softirq in kcov_remote_stop()
  scripts/spelling: add a few more typos
  khugepaged: selftests: fix timeout condition in wait_for_scan()

5 files changed, 12 insertions, 70 deletions

diff --git a/mm/Makefile b/mm/Makefile
index 662fd1504646..cc8f897dfac0 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -41,7 +41,7 @@ obj-y			:= filemap.o mempool.o oom_kill.o fadvise.o \
 			   maccess.o page-writeback.o \
 			   readahead.o swap.o truncate.o vmscan.o shmem.o \
 			   util.o mmzone.o vmstat.o backing-dev.o \
-			   mm_init.o mmu_context.o percpu.o slab_common.o \
+			   mm_init.o percpu.o slab_common.o \
 			   compaction.o vmacache.o \
 			   interval_tree.o list_lru.o workingset.o \
 			   debug.o gup.o $(mmu-y)
diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index 9ec59c38d6a2..e45623016aea 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -60,6 +60,9 @@ static void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot)
 {
 	pmd_t pmd = pfn_pmd(pfn, prot);
 
+	if (!has_transparent_hugepage())
+		return;
+
 	WARN_ON(!pmd_same(pmd, pmd));
 	WARN_ON(!pmd_young(pmd_mkyoung(pmd_mkold(pmd))));
 	WARN_ON(!pmd_dirty(pmd_mkdirty(pmd_mkclean(pmd))));
@@ -79,6 +82,9 @@ static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot)
 {
 	pud_t pud = pfn_pud(pfn, prot);
 
+	if (!has_transparent_hugepage())
+		return;
+
 	WARN_ON(!pud_same(pud, pud));
 	WARN_ON(!pud_young(pud_mkyoung(pud_mkold(pud))));
 	WARN_ON(!pud_write(pud_mkwrite(pud_wrprotect(pud))));
diff --git a/mm/mmu_context.c b/mm/mmu_context.c
deleted file mode 100644
index 3e612ae748e9..000000000000
--- a/mm/mmu_context.c
+++ /dev/null
@@ -1,64 +0,0 @@
-/* Copyright (C) 2009 Red Hat, Inc.
- *
- * See ../COPYING for licensing terms.
- */
-
-#include <linux/mm.h>
-#include <linux/sched.h>
-#include <linux/sched/mm.h>
-#include <linux/sched/task.h>
-#include <linux/mmu_context.h>
-#include <linux/export.h>
-
-#include <asm/mmu_context.h>
-
-/*
- * use_mm
- *	Makes the calling kernel thread take on the specified
- *	mm context.
- *	(Note: this routine is intended to be called only
- *	from a kernel thread context)
- */
-void use_mm(struct mm_struct *mm)
-{
-	struct mm_struct *active_mm;
-	struct task_struct *tsk = current;
-
-	task_lock(tsk);
-	active_mm = tsk->active_mm;
-	if (active_mm != mm) {
-		mmgrab(mm);
-		tsk->active_mm = mm;
-	}
-	tsk->mm = mm;
-	switch_mm(active_mm, mm, tsk);
-	task_unlock(tsk);
-#ifdef finish_arch_post_lock_switch
-	finish_arch_post_lock_switch();
-#endif
-
-	if (active_mm != mm)
-		mmdrop(active_mm);
-}
-EXPORT_SYMBOL_GPL(use_mm);
-
-/*
- * unuse_mm
- *	Reverses the effect of use_mm, i.e. releases the
- *	specified mm context which was earlier taken on
- *	by the calling kernel thread
- *	(Note: this routine is intended to be called only
- *	from a kernel thread context)
- */
-void unuse_mm(struct mm_struct *mm)
-{
-	struct task_struct *tsk = current;
-
-	task_lock(tsk);
-	sync_mm_rss(mm);
-	tsk->mm = NULL;
-	/* active_mm is still 'mm' */
-	enter_lazy_tlb(mm, tsk);
-	task_unlock(tsk);
-}
-EXPORT_SYMBOL_GPL(unuse_mm);
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index b4e9491cb320..6e94962893ee 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -126,7 +126,7 @@ static bool oom_cpuset_eligible(struct task_struct *tsk, struct oom_control *oc)
 
 /*
  * The process p may have detached its own ->mm while exiting or through
- * use_mm(), but one or more of its subthreads may still have a valid
+ * kthread_use_mm(), but one or more of its subthreads may still have a valid
  * pointer.  Return p, or any of its subthreads with a valid ->mm, with
  * task_lock() held.
  */
@@ -919,8 +919,8 @@ static void __oom_kill_process(struct task_struct *victim, const char *message)
 			continue;
 		}
 		/*
-		 * No use_mm() user needs to read from the userspace so we are
-		 * ok to reap it.
+		 * No kthead_use_mm() user needs to read from the userspace so
+		 * we are ok to reap it.
 		 */
 		if (unlikely(p->flags & PF_KTHREAD))
 			continue;
diff --git a/mm/vmacache.c b/mm/vmacache.c
index d9092814c772..01a6e6688ec1 100644
--- a/mm/vmacache.c
+++ b/mm/vmacache.c
@@ -24,8 +24,8 @@
  * task's vmacache pertains to a different mm (ie, its own).  There is
  * nothing we can do here.
  *
- * Also handle the case where a kernel thread has adopted this mm via use_mm().
- * That kernel thread's vmacache is not applicable to this mm.
+ * Also handle the case where a kernel thread has adopted this mm via
+ * kthread_use_mm(). That kernel thread's vmacache is not applicable to this mm.
  */
 static inline bool vmacache_valid_mm(struct mm_struct *mm)
 {