Re: [PATCH v12 33/69] powerpc: remove mmap linked list walks

Link: https://lkml.kernel.org/r/20220504011345.662299-18-Liam.Howlett@oracle.com
Link: https://lkml.kernel.org/r/20220621204632.3370049-34-Liam.Howlett@oracle.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Liam R. Howlett <redacted>
Reviewed-by: Vlastimil Babka <redacted>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
  arch/powerpc/kernel/vdso.c              |  6 +++---
  arch/powerpc/mm/book3s32/tlb.c          | 11 ++++++-----
  arch/powerpc/mm/book3s64/subpage_prot.c | 13 ++-----------
  3 files changed, 11 insertions(+), 19 deletions(-)

diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index 0da287544054..94a8fa5017c3 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c

@@ -113,18 +113,18 @@ struct vdso_data *arch_get_vdso_data(void *vvar_page)
  int vdso_join_timens(struct task_struct *task, struct time_namespace *ns)
  {
  	struct mm_struct *mm = task->mm;
+	VMA_ITERATOR(vmi, mm, 0);
  	struct vm_area_struct *vma;
  
  	mmap_read_lock(mm);
-
-	for (vma = mm->mmap; vma; vma = vma->vm_next) {
+	for_each_vma(vmi, vma) {
  		unsigned long size = vma->vm_end - vma->vm_start;
  
  		if (vma_is_special_mapping(vma, &vvar_spec))
  			zap_page_range(vma, vma->vm_start, size);
  	}
-
  	mmap_read_unlock(mm);
+
  	return 0;
  }
  

diff --git a/arch/powerpc/mm/book3s32/tlb.c b/arch/powerpc/mm/book3s32/tlb.c
index 19f0ef950d77..9ad6b56bfec9 100644
--- a/arch/powerpc/mm/book3s32/tlb.c
+++ b/arch/powerpc/mm/book3s32/tlb.c

@@ -81,14 +81,15 @@ EXPORT_SYMBOL(hash__flush_range);
  void hash__flush_tlb_mm(struct mm_struct *mm)
  {
  	struct vm_area_struct *mp;
+	VMA_ITERATOR(vmi, mm, 0);
  
  	/*
-	 * It is safe to go down the mm's list of vmas when called
-	 * from dup_mmap, holding mmap_lock.  It would also be safe from
-	 * unmap_region or exit_mmap, but not from vmtruncate on SMP -
-	 * but it seems dup_mmap is the only SMP case which gets here.
+	 * It is safe to iterate the vmas when called from dup_mmap,
+	 * holding mmap_lock.  It would also be safe from unmap_region
+	 * or exit_mmap, but not from vmtruncate on SMP - but it seems
+	 * dup_mmap is the only SMP case which gets here.
  	 */
-	for (mp = mm->mmap; mp != NULL; mp = mp->vm_next)
+	for_each_vma(vmi, mp)
  		hash__flush_range(mp->vm_mm, mp->vm_start, mp->vm_end);
  }
  EXPORT_SYMBOL(hash__flush_tlb_mm);

diff --git a/arch/powerpc/mm/book3s64/subpage_prot.c b/arch/powerpc/mm/book3s64/subpage_prot.c
index 60c6ea16a972..d73b3b4176e8 100644
--- a/arch/powerpc/mm/book3s64/subpage_prot.c
+++ b/arch/powerpc/mm/book3s64/subpage_prot.c

@@ -149,24 +149,15 @@ static void subpage_mark_vma_nohuge(struct mm_struct *mm, unsigned long addr,
  				    unsigned long len)
  {
  	struct vm_area_struct *vma;
+	VMA_ITERATOR(vmi, mm, addr);
  
  	/*
  	 * We don't try too hard, we just mark all the vma in that range
  	 * VM_NOHUGEPAGE and split them.
  	 */
-	vma = find_vma(mm, addr);
-	/*
-	 * If the range is in unmapped range, just return
-	 */
-	if (vma && ((addr + len) <= vma->vm_start))
-		return;
-
-	while (vma) {
-		if (vma->vm_start >= (addr + len))
-			break;
+	for_each_vma_range(vmi, vma, addr + len) {
  		vma->vm_flags |= VM_NOHUGEPAGE;
  		walk_page_vma(vma, &subpage_walk_ops, NULL);
-		vma = vma->vm_next;
  	}
  }
  #else