Merge tag 'v4.8' into patchwork

Linux 4.8

* tag 'v4.8': (1761 commits)
  Linux 4.8
  ARM: 8618/1: decompressor: reset ttbcr fields to use TTBR0 on ARMv7
  MIPS: CM: Fix mips_cm_max_vp_width for non-MT kernels on MT systems
  include/linux/property.h: fix typo/compile error
  ocfs2: fix deadlock on mmapped page in ocfs2_write_begin_nolock()
  mm: workingset: fix crash in shadow node shrinker caused by replace_page_cache_page()
  MAINTAINERS: Switch to kernel.org email address for Javi Merino
  x86/entry/64: Fix context tracking state warning when load_gs_index fails
  x86/boot: Initialize FPU and X86_FEATURE_ALWAYS even if we don't have CPUID
  x86/vdso: Fix building on big endian host
  x86/boot: Fix another __read_cr4() case on 486
  sctp: fix the issue sctp_diag uses lock_sock in rcu_read_lock
  sctp: change to check peer prsctp_capable when using prsctp polices
  sctp: remove prsctp_param from sctp_chunk
  sctp: move sent_count to the memory hole in sctp_chunk
  tg3: Avoid NULL pointer dereference in tg3_io_error_detected()
  x86/init: Fix cr4_init_shadow() on CR4-less machines
  MIPS: Fix detection of unsupported highmem with cache aliases
  MIPS: Malta: Fix IOCU disable switch read for MIPS64
  MIPS: Fix BUILD_ROLLBACK_PROLOGUE for microMIPS
  ...

1 files changed, 31 insertions, 4 deletions

diff --git a/arch/sparc/mm/tlb.c b/arch/sparc/mm/tlb.c
index 3659d37b4d81..c56a195c9071 100644
--- a/arch/sparc/mm/tlb.c
+++ b/arch/sparc/mm/tlb.c
@@ -174,10 +174,25 @@ void set_pmd_at(struct mm_struct *mm, unsigned long addr,
 		return;
 
 	if ((pmd_val(pmd) ^ pmd_val(orig)) & _PAGE_PMD_HUGE) {
-		if (pmd_val(pmd) & _PAGE_PMD_HUGE)
-			mm->context.thp_pte_count++;
-		else
-			mm->context.thp_pte_count--;
+		/*
+		 * Note that this routine only sets pmds for THP pages.
+		 * Hugetlb pages are handled elsewhere.  We need to check
+		 * for huge zero page.  Huge zero pages are like hugetlb
+		 * pages in that there is no RSS, but there is the need
+		 * for TSB entries.  So, huge zero page counts go into
+		 * hugetlb_pte_count.
+		 */
+		if (pmd_val(pmd) & _PAGE_PMD_HUGE) {
+			if (is_huge_zero_page(pmd_page(pmd)))
+				mm->context.hugetlb_pte_count++;
+			else
+				mm->context.thp_pte_count++;
+		} else {
+			if (is_huge_zero_page(pmd_page(orig)))
+				mm->context.hugetlb_pte_count--;
+			else
+				mm->context.thp_pte_count--;
+		}
 
 		/* Do not try to allocate the TSB hash table if we
 		 * don't have one already.  We have various locks held
@@ -204,6 +219,9 @@ void set_pmd_at(struct mm_struct *mm, unsigned long addr,
 	}
 }
 
+/*
+ * This routine is only called when splitting a THP
+ */
 void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 		     pmd_t *pmdp)
 {
@@ -213,6 +231,15 @@ void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 
 	set_pmd_at(vma->vm_mm, address, pmdp, entry);
 	flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
+
+	/*
+	 * set_pmd_at() will not be called in a way to decrement
+	 * thp_pte_count when splitting a THP, so do it now.
+	 * Sanity check pmd before doing the actual decrement.
+	 */
+	if ((pmd_val(entry) & _PAGE_PMD_HUGE) &&
+	    !is_huge_zero_page(pmd_page(entry)))
+		(vma->vm_mm)->context.thp_pte_count--;
 }
 
 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,