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()

4 files changed, 19 insertions, 7 deletions

diff --git a/include/linux/kthread.h b/include/linux/kthread.h
index c2a274b79c42..65b81e0c494d 100644
--- a/include/linux/kthread.h
+++ b/include/linux/kthread.h
@@ -5,6 +5,8 @@
 #include <linux/err.h>
 #include <linux/sched.h>
 
+struct mm_struct;
+
 __printf(4, 5)
 struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
 					   void *data,
@@ -199,6 +201,9 @@ bool kthread_cancel_delayed_work_sync(struct kthread_delayed_work *work);
 
 void kthread_destroy_worker(struct kthread_worker *worker);
 
+void kthread_use_mm(struct mm_struct *mm);
+void kthread_unuse_mm(struct mm_struct *mm);
+
 struct cgroup_subsys_state;
 
 #ifdef CONFIG_BLK_CGROUP
diff --git a/include/linux/mmu_context.h b/include/linux/mmu_context.h
index d9a543a9e1cc..c51a84132d7c 100644
--- a/include/linux/mmu_context.h
+++ b/include/linux/mmu_context.h
@@ -4,11 +4,6 @@
 
 #include <asm/mmu_context.h>
 
-struct mm_struct;
-
-void use_mm(struct mm_struct *mm);
-void unuse_mm(struct mm_struct *mm);
-
 /* Architectures that care about IRQ state in switch_mm can override this. */
 #ifndef switch_mm_irqs_off
 # define switch_mm_irqs_off switch_mm
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index df1f08486d81..c4c37fd12104 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -660,9 +660,21 @@ struct deferred_split {
  * per-zone basis.
  */
 typedef struct pglist_data {
+	/*
+	 * node_zones contains just the zones for THIS node. Not all of the
+	 * zones may be populated, but it is the full list. It is referenced by
+	 * this node's node_zonelists as well as other node's node_zonelists.
+	 */
 	struct zone node_zones[MAX_NR_ZONES];
+
+	/*
+	 * node_zonelists contains references to all zones in all nodes.
+	 * Generally the first zones will be references to this node's
+	 * node_zones.
+	 */
 	struct zonelist node_zonelists[MAX_ZONELISTS];
-	int nr_zones;
+
+	int nr_zones; /* number of populated zones in this node */
 #ifdef CONFIG_FLAT_NODE_MEM_MAP	/* means !SPARSEMEM */
 	struct page *node_mem_map;
 #ifdef CONFIG_PAGE_EXTENSION
diff --git a/include/linux/stacktrace.h b/include/linux/stacktrace.h
index 83bd8cb475d7..b7af8cc13eda 100644
--- a/include/linux/stacktrace.h
+++ b/include/linux/stacktrace.h
@@ -64,7 +64,7 @@ void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie,
 struct stack_trace {
 	unsigned int nr_entries, max_entries;
 	unsigned long *entries;
-	int skip;	/* input argument: How many entries to skip */
+	unsigned int skip;	/* input argument: How many entries to skip */
 };
 
 extern void save_stack_trace(struct stack_trace *trace);