Date:   Mon, 27 Feb 2023 09:36:13 -0800
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Subject: [PATCH v4 14/33] mm/mmap: move vma_prepare before vma_adjust_trans_huge
From:   Suren Baghdasaryan <surenb@google.com>
To:     akpm@linux-foundation.org
Cc:     michel@lespinasse.org, jglisse@google.com, mhocko@suse.com,
        vbabka@suse.cz, hannes@cmpxchg.org, mgorman@techsingularity.net,
        dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com,
        peterz@infradead.org, ldufour@linux.ibm.com, paulmck@kernel.org,
        mingo@redhat.com, will@kernel.org, luto@kernel.org,
        songliubraving@fb.com, peterx@redhat.com, david@redhat.com,
        dhowells@redhat.com, hughd@google.com, bigeasy@linutronix.de,
        kent.overstreet@linux.dev, punit.agrawal@bytedance.com,
        lstoakes@gmail.com, peterjung1337@gmail.com, rientjes@google.com,
        chriscli@google.com, axelrasmussen@google.com, joelaf@google.com,
        minchan@google.com, rppt@kernel.org, jannh@google.com,
        shakeelb@google.com, tatashin@google.com, edumazet@google.com,
        gthelen@google.com, gurua@google.com, arjunroy@google.com,
        soheil@google.com, leewalsh@google.com, posk@google.com,
        michalechner92@googlemail.com, linux-mm@kvack.org,
        linux-arm-kernel@lists.infradead.org,
        linuxppc-dev@lists.ozlabs.org, x86@kernel.org,
        linux-kernel@vger.kernel.org, kernel-team@android.com,
        Suren Baghdasaryan <surenb@google.com>
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Precedence: bulk

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 <surenb@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