From daf0b0fc4a07a13fd8016c09d8425e25a2f59027 Mon Sep 17 00:00:00 2001
From: Lokesh Gidra <lokeshgidra@google.com>
Date: Thu, 15 Feb 2024 10:27:55 -0800
Subject: [PATCH] BACKPORT: mm: add vma_assert_locked() for
 !CONFIG_PER_VMA_LOCK

vma_assert_locked() is needed to replace mmap_assert_locked() once we
start using per-vma locks in userfaultfd operations.

In !CONFIG_PER_VMA_LOCK case when mm is locked, it implies that the given
VMA is locked.

Link: https://lkml.kernel.org/r/20240215182756.3448972-4-lokeshgidra@google.com
Signed-off-by: Lokesh Gidra <lokeshgidra@google.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Nicolas Geoffray <ngeoffray@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Tim Murray <timmurray@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

(cherry picked from commit 32af81af2f6f4c23b1b4ff68410e91da660af102)
Conflicts:
	include/linux/mm.h

1. lock_vma_under_rcu() definition in !CONFIG_PER_VMA_LOCK case doesn't
   exist in 6.1. Resolved cherry-pick conflict due to that.

Bug: 320478828
Change-Id: I76d414cd08c3d696d3886921a7e27cf94fd17b76
Signed-off-by: Lokesh Gidra <lokeshgidra@google.com>
---
 include/linux/mm.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 4082f86f8f9f..a17bd3a6413f 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -780,6 +780,11 @@ static inline void vma_assert_write_locked(struct vm_area_struct *vma)
 static inline void vma_mark_detached(struct vm_area_struct *vma,
 				     bool detached) {}
 
+static inline void vma_assert_locked(struct vm_area_struct *vma)
+{
+	mmap_assert_locked(vma->vm_mm);
+}
+
 static inline void release_fault_lock(struct vm_fault *vmf)
 {
 	mmap_read_unlock(vmf->vma->vm_mm);