Merge branch 'akpm' (fixes from Andrew Morton)

Merge patch-bomb from Andrew Morton:
 - part of OCFS2 (review is laggy again)
 - procfs
 - slab
 - all of MM
 - zram, zbud
 - various other random things: arch, filesystems.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (164 commits)
  nosave: consolidate __nosave_{begin,end} in <asm/sections.h>
  include/linux/screen_info.h: remove unused ORIG_* macros
  kernel/sys.c: compat sysinfo syscall: fix undefined behavior
  kernel/sys.c: whitespace fixes
  acct: eliminate compile warning
  kernel/async.c: switch to pr_foo()
  include/linux/blkdev.h: use NULL instead of zero
  include/linux/kernel.h: deduplicate code implementing clamp* macros
  include/linux/kernel.h: rewrite min3, max3 and clamp using min and max
  alpha: use Kbuild logic to include <asm-generic/sections.h>
  frv: remove deprecated IRQF_DISABLED
  frv: remove unused cpuinfo_frv and friends to fix future build error
  zbud: avoid accessing last unused freelist
  zsmalloc: simplify init_zspage free obj linking
  mm/zsmalloc.c: correct comment for fullness group computation
  zram: use notify_free to account all free notifications
  zram: report maximum used memory
  zram: zram memory size limitation
  zsmalloc: change return value unit of zs_get_total_size_bytes
  zsmalloc: move pages_allocated to zs_pool
  ...

1 files changed, 11 insertions, 17 deletions

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index f8ffd94..74c78aa 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1096,7 +1096,7 @@ int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	unsigned long mmun_end;		/* For mmu_notifiers */
 
 	ptl = pmd_lockptr(mm, pmd);
-	VM_BUG_ON(!vma->anon_vma);
+	VM_BUG_ON_VMA(!vma->anon_vma, vma);
 	haddr = address & HPAGE_PMD_MASK;
 	if (is_huge_zero_pmd(orig_pmd))
 		goto alloc;
@@ -2048,7 +2048,7 @@ int __khugepaged_enter(struct mm_struct *mm)
 		return -ENOMEM;
 
 	/* __khugepaged_exit() must not run from under us */
-	VM_BUG_ON(khugepaged_test_exit(mm));
+	VM_BUG_ON_MM(khugepaged_test_exit(mm), mm);
 	if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) {
 		free_mm_slot(mm_slot);
 		return 0;
@@ -2083,7 +2083,7 @@ int khugepaged_enter_vma_merge(struct vm_area_struct *vma)
 	if (vma->vm_ops)
 		/* khugepaged not yet working on file or special mappings */
 		return 0;
-	VM_BUG_ON(vma->vm_flags & VM_NO_THP);
+	VM_BUG_ON_VMA(vma->vm_flags & VM_NO_THP, vma);
 	hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
 	hend = vma->vm_end & HPAGE_PMD_MASK;
 	if (hstart < hend)
@@ -2322,23 +2322,17 @@ static struct page
 		       int node)
 {
 	VM_BUG_ON_PAGE(*hpage, *hpage);
+
 	/*
-	 * Allocate the page while the vma is still valid and under
-	 * the mmap_sem read mode so there is no memory allocation
-	 * later when we take the mmap_sem in write mode. This is more
-	 * friendly behavior (OTOH it may actually hide bugs) to
-	 * filesystems in userland with daemons allocating memory in
-	 * the userland I/O paths.  Allocating memory with the
-	 * mmap_sem in read mode is good idea also to allow greater
-	 * scalability.
+	 * Before allocating the hugepage, release the mmap_sem read lock.
+	 * The allocation can take potentially a long time if it involves
+	 * sync compaction, and we do not need to hold the mmap_sem during
+	 * that. We will recheck the vma after taking it again in write mode.
 	 */
+	up_read(&mm->mmap_sem);
+
 	*hpage = alloc_pages_exact_node(node, alloc_hugepage_gfpmask(
 		khugepaged_defrag(), __GFP_OTHER_NODE), HPAGE_PMD_ORDER);
-	/*
-	 * After allocating the hugepage, release the mmap_sem read lock in
-	 * preparation for taking it in write mode.
-	 */
-	up_read(&mm->mmap_sem);
 	if (unlikely(!*hpage)) {
 		count_vm_event(THP_COLLAPSE_ALLOC_FAILED);
 		*hpage = ERR_PTR(-ENOMEM);
@@ -2412,7 +2406,7 @@ static bool hugepage_vma_check(struct vm_area_struct *vma)
 		return false;
 	if (is_vma_temporary_stack(vma))
 		return false;
-	VM_BUG_ON(vma->vm_flags & VM_NO_THP);
+	VM_BUG_ON_VMA(vma->vm_flags & VM_NO_THP, vma);
 	return true;
 }