Received-SPF: pass (google.com: domain of linux-kernel+bounces-160279-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45e3:2400::1 as permitted sender) client-ip=2604:1380:45e3:2400::1;
Precedence: bulk
MIME-Version: 1.0
References: <20240426144506.1290619-1-willy@infradead.org> <20240426144506.1290619-2-willy@infradead.org>
In-Reply-To: <20240426144506.1290619-2-willy@infradead.org>
From: Suren Baghdasaryan <surenb@google.com>
Date: Fri, 26 Apr 2024 08:23:47 -0700
Message-ID: <CAJuCfpH_kyp6vVU5dSx=WJNpGRThmak53wVjSsBfxtqTrNy8TQ@mail.gmail.com>
Subject: Re: [PATCH 1/4] mm: Assert the mmap_lock is held in __anon_vma_prepare()
To: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org, 
	linux-kernel@vger.kernel.org, Peter Xu <peterx@redhat.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

On Fri, Apr 26, 2024 at 7:45=E2=80=AFAM Matthew Wilcox (Oracle)
<willy@infradead.org> wrote:
>
> Convert the comment into an assertion.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Reviewed-by: Suren Baghdasaryan <surenb@google.com>

> ---
>  mm/rmap.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 2608c40dffad..619d4d65d99b 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -182,8 +182,6 @@ static void anon_vma_chain_link(struct vm_area_struct=
 *vma,
>   * for the new allocation. At the same time, we do not want
>   * to do any locking for the common case of already having
>   * an anon_vma.
> - *
> - * This must be called with the mmap_lock held for reading.
>   */
>  int __anon_vma_prepare(struct vm_area_struct *vma)
>  {
> @@ -191,6 +189,7 @@ int __anon_vma_prepare(struct vm_area_struct *vma)
>         struct anon_vma *anon_vma, *allocated;
>         struct anon_vma_chain *avc;
>
> +       mmap_assert_locked(mm);
>         might_sleep();
>
>         avc =3D anon_vma_chain_alloc(GFP_KERNEL);
> --
> 2.43.0
>