inline attachment example

> > > + down_write(&mm->mmap_sem);
> > > + result = hugepage_vma_revalidate(mm, vma, address);
> > > + if (result)
> > > +         goto out;
> > >
> > >   anon_vma_lock_write(vma->anon_vma);
> >
> > Didn't Kirill have a concern that the vma might go away after up_read
> > and before down_write?
>
> hugepage_vma_revalidate does the revalidation. Scratch my comment. Sorry
> about the noise. I just saw the vma still being used and that raised a
> flag. I should have looked into hugepage_vma_revalidate to see that vma
> is not actually used and it can be dropped.

One thing to notice is that passing 'vma' to hugepage_vma_revlidate() is
useless. It doesn't make use of it anyway.

Fixup:

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 292cedd9d692..b17c84095059 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2386,10 +2386,9 @@ static bool hugepage_vma_check(struct vm_area_struct *vma)
  * value (scan code).
  */

-static int hugepage_vma_revalidate(struct mm_struct *mm,
-                                  struct vm_area_struct *vma,
-                                  unsigned long address)
+static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address)
 {
+       struct vm_area_struct *vma;
        unsigned long hstart, hend;

        if (unlikely(khugepaged_test_exit(mm)))
@@ -2438,7 +2437,7 @@ static bool __collapse_huge_page_swapin(struct mm_struct *mm,
                if (ret & VM_FAULT_RETRY) {
                        down_read(&mm->mmap_sem);
                        /* vma is no longer available, don't continue to swapin */
-                       if (hugepage_vma_revalidate(mm, vma, address))
+                       if (hugepage_vma_revalidate(mm, address))
                                return false;
                }
                if (ret & VM_FAULT_ERROR) {
@@ -2492,7 +2491,7 @@ static void collapse_huge_page(struct mm_struct *mm,
        swap = get_mm_counter(mm, MM_SWAPENTS);
        curr_allocstall = sum_vm_event(ALLOCSTALL);
        down_read(&mm->mmap_sem);
-       result = hugepage_vma_revalidate(mm, vma, address);
+       result = hugepage_vma_revalidate(mm, address);
        if (result)
                goto out;

@@ -2525,7 +2524,7 @@ static void collapse_huge_page(struct mm_struct *mm,
         * handled by the anon_vma lock + PG_lock.
         */
        down_write(&mm->mmap_sem);
-       result = hugepage_vma_revalidate(mm, vma, address);
+       result = hugepage_vma_revalidate(mm, address);
        if (result)
                goto out;