Merge branch 'akpm' (patches from Andrew)

Merge yet more updates from Andrew Morton:
 "The rest of MM and a kernel-wide procfs cleanup.

  Summary of the more significant patches:

   - Patch series "mm/memory_hotplug: Factor out memory block
     devicehandling", v3. David Hildenbrand.

     Some spring-cleaning of the memory hotplug code, notably in
     drivers/base/memory.c

   - "mm: thp: fix false negative of shmem vma's THP eligibility". Yang
     Shi.

     Fix /proc/pid/smaps output for THP pages used in shmem.

   - "resource: fix locking in find_next_iomem_res()" + 1. Nadav Amit.

     Bugfix and speedup for kernel/resource.c

   - Patch series "mm: Further memory block device cleanups", David
     Hildenbrand.

     More spring-cleaning of the memory hotplug code.

   - Patch series "mm: Sub-section memory hotplug support". Dan
     Williams.

     Generalise the memory hotplug code so that pmem can use it more
     completely. Then remove the hacks from the libnvdimm code which
     were there to work around the memory-hotplug code's constraints.

   - "proc/sysctl: add shared variables for range check", Matteo Croce.

     We have about 250 instances of

          int zero;
          ...
                  .extra1 = &zero,

     in the tree. This is a tree-wide sweep to make all those private
     "zero"s and "one"s use global variables.

     Alas, it isn't practical to make those two global integers const"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (38 commits)
  proc/sysctl: add shared variables for range check
  mm: migrate: remove unused mode argument
  mm/sparsemem: cleanup 'section number' data types
  libnvdimm/pfn: stop padding pmem namespaces to section alignment
  libnvdimm/pfn: fix fsdax-mode namespace info-block zero-fields
  mm/devm_memremap_pages: enable sub-section remap
  mm: document ZONE_DEVICE memory-model implications
  mm/sparsemem: support sub-section hotplug
  mm/sparsemem: prepare for sub-section ranges
  mm: kill is_dev_zone() helper
  mm/hotplug: kill is_dev_zone() usage in __remove_pages()
  mm/sparsemem: convert kmalloc_section_memmap() to populate_section_memmap()
  mm/hotplug: prepare shrink_{zone, pgdat}_span for sub-section removal
  mm/sparsemem: add helpers track active portions of a section at boot
  mm/sparsemem: introduce a SECTION_IS_EARLY flag
  mm/sparsemem: introduce struct mem_section_usage
  drivers/base/memory.c: get rid of find_memory_block_hinted()
  mm/memory_hotplug: move and simplify walk_memory_blocks()
  mm/memory_hotplug: rename walk_memory_range() and pass start+size instead of pfns
  mm: make register_mem_sect_under_node() static
  ...

1 files changed, 32 insertions, 17 deletions

diff --git a/kernel/resource.c b/kernel/resource.c
index d22423e85cf8..7ea4306503c5 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -326,7 +326,7 @@ EXPORT_SYMBOL(release_resource);
  *
  * If a resource is found, returns 0 and @*res is overwritten with the part
  * of the resource that's within [@start..@end]; if none is found, returns
- * -1 or -EINVAL for other invalid parameters.
+ * -ENODEV.  Returns -EINVAL for invalid parameters.
  *
  * This function walks the whole tree and not just first level children
  * unless @first_lvl is true.
@@ -342,6 +342,7 @@ static int find_next_iomem_res(resource_size_t start, resource_size_t end,
 			       unsigned long flags, unsigned long desc,
 			       bool first_lvl, struct resource *res)
 {
+	bool siblings_only = true;
 	struct resource *p;
 
 	if (!res)
@@ -352,29 +353,43 @@ static int find_next_iomem_res(resource_size_t start, resource_size_t end,
 
 	read_lock(&resource_lock);
 
-	for (p = iomem_resource.child; p; p = next_resource(p, first_lvl)) {
-		if ((p->flags & flags) != flags)
-			continue;
-		if ((desc != IORES_DESC_NONE) && (desc != p->desc))
-			continue;
+	for (p = iomem_resource.child; p; p = next_resource(p, siblings_only)) {
+		/* If we passed the resource we are looking for, stop */
 		if (p->start > end) {
 			p = NULL;
 			break;
 		}
-		if ((p->end >= start) && (p->start <= end))
-			break;
+
+		/* Skip until we find a range that matches what we look for */
+		if (p->end < start)
+			continue;
+
+		/*
+		 * Now that we found a range that matches what we look for,
+		 * check the flags and the descriptor. If we were not asked to
+		 * use only the first level, start looking at children as well.
+		 */
+		siblings_only = first_lvl;
+
+		if ((p->flags & flags) != flags)
+			continue;
+		if ((desc != IORES_DESC_NONE) && (desc != p->desc))
+			continue;
+
+		/* Found a match, break */
+		break;
+	}
+
+	if (p) {
+		/* copy data */
+		res->start = max(start, p->start);
+		res->end = min(end, p->end);
+		res->flags = p->flags;
+		res->desc = p->desc;
 	}
 
 	read_unlock(&resource_lock);
-	if (!p)
-		return -1;
-
-	/* copy data */
-	res->start = max(start, p->start);
-	res->end = min(end, p->end);
-	res->flags = p->flags;
-	res->desc = p->desc;
-	return 0;
+	return p ? 0 : -ENODEV;
 }
 
 static int __walk_iomem_res_desc(resource_size_t start, resource_size_t end,