Date:   Thu, 9 Dec 2021 09:55:56 +0100
From:   Michal Hocko <mhocko@suse.com>
To:     Suren Baghdasaryan <surenb@google.com>
Cc:     akpm@linux-foundation.org, rientjes@google.com,
        willy@infradead.org, hannes@cmpxchg.org, guro@fb.com,
        riel@surriel.com, minchan@kernel.org, kirill@shutemov.name,
        aarcange@redhat.com, christian@brauner.io, hch@infradead.org,
        oleg@redhat.com, david@redhat.com, jannh@google.com,
        shakeelb@google.com, luto@kernel.org, christian.brauner@ubuntu.com,
        fweimer@redhat.com, jengelh@inai.de, timmurray@google.com,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        kernel-team@android.com
Subject: Re: [PATCH v4 2/3] mm: document locking restrictions for
 vm_operations_struct::close
Message-ID: <YbHEnFdjECnM2r20@dhcp22.suse.cz>
References: <20211208212211.2860249-1-surenb@google.com>
 <20211208212211.2860249-2-surenb@google.com>
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On Wed 08-12-21 13:22:10, Suren Baghdasaryan wrote:
> Add comments for vm_operations_struct::close documenting locking
> requirements for this callback and its callers.
> 
> Signed-off-by: Suren Baghdasaryan <surenb@google.com>

Acked-by: Michal Hocko <mhocko@suse.com>

> ---
>  include/linux/mm.h | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index a7e4a9e7d807..b9b88ba7564b 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -577,6 +577,10 @@ enum page_entry_size {
>   */
>  struct vm_operations_struct {
>  	void (*open)(struct vm_area_struct * area);
> +	/**
> +	 * @close: Called when the VMA is being removed from the MM.
> +	 * Context: User context.  May sleep.  Caller holds mmap_lock.
> +	 */
>  	void (*close)(struct vm_area_struct * area);
>  	/* Called any time before splitting to check if it's allowed */
>  	int (*may_split)(struct vm_area_struct *area, unsigned long addr);
> -- 
> 2.34.1.400.ga245620fadb-goog

-- 
Michal Hocko
SUSE Labs