[PATCH v4 14/33] mm/mmap: move vma_prepare before vma_adjust_trans_huge

[Suren Baghdasaryan]

vma_prepare() acquires all locks required before VMA modifications.
Move vma_prepare() before vma_adjust_trans_huge() so that VMA is locked
before any modification.

Signed-off-by: Suren Baghdasaryan <sur...@google.com>
---
 mm/mmap.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index c234443ee24c..92893d86c0af 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -683,12 +683,12 @@ int vma_expand(struct vma_iterator *vmi, struct 
vm_area_struct *vma,
        if (vma_iter_prealloc(vmi))
                goto nomem;
 
+       vma_prepare(&vp);
        vma_adjust_trans_huge(vma, start, end, 0);
        /* VMA iterator points to previous, so set to start if necessary */
        if (vma_iter_addr(vmi) != start)
                vma_iter_set(vmi, start);
 
-       vma_prepare(&vp);
        vma->vm_start = start;
        vma->vm_end = end;
        vma->vm_pgoff = pgoff;
@@ -723,8 +723,8 @@ int vma_shrink(struct vma_iterator *vmi, struct 
vm_area_struct *vma,
                return -ENOMEM;
 
        init_vma_prep(&vp, vma);
-       vma_adjust_trans_huge(vma, start, end, 0);
        vma_prepare(&vp);
+       vma_adjust_trans_huge(vma, start, end, 0);
 
        if (vma->vm_start < start)
                vma_iter_clear(vmi, vma->vm_start, start);
@@ -994,12 +994,12 @@ struct vm_area_struct *vma_merge(struct vma_iterator 
*vmi, struct mm_struct *mm,
        if (vma_iter_prealloc(vmi))
                return NULL;
 
-       vma_adjust_trans_huge(vma, vma_start, vma_end, adj_next);
        init_multi_vma_prep(&vp, vma, adjust, remove, remove2);
        VM_WARN_ON(vp.anon_vma && adjust && adjust->anon_vma &&
                   vp.anon_vma != adjust->anon_vma);
 
        vma_prepare(&vp);
+       vma_adjust_trans_huge(vma, vma_start, vma_end, adj_next);
        if (vma_start < vma->vm_start || vma_end > vma->vm_end)
                vma_expanded = true;
 
@@ -2198,10 +2198,10 @@ int __split_vma(struct vma_iterator *vmi, struct 
vm_area_struct *vma,
        if (new->vm_ops && new->vm_ops->open)
                new->vm_ops->open(new);
 
-       vma_adjust_trans_huge(vma, vma->vm_start, addr, 0);
        init_vma_prep(&vp, vma);
        vp.insert = new;
        vma_prepare(&vp);
+       vma_adjust_trans_huge(vma, vma->vm_start, addr, 0);
 
        if (new_below) {
                vma->vm_start = addr;
@@ -2910,9 +2910,9 @@ static int do_brk_flags(struct vma_iterator *vmi, struct 
vm_area_struct *vma,
                if (vma_iter_prealloc(vmi))
                        goto unacct_fail;
 
-               vma_adjust_trans_huge(vma, vma->vm_start, addr + len, 0);
                init_vma_prep(&vp, vma);
                vma_prepare(&vp);
+               vma_adjust_trans_huge(vma, vma->vm_start, addr + len, 0);
                vma->vm_end = addr + len;
                vm_flags_set(vma, VM_SOFTDIRTY);
                vma_iter_store(vmi, vma);
-- 
2.39.2.722.g9855ee24e9-goog