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From:   David Laight <David.Laight@ACULAB.COM>
To:     'Arnd Bergmann' <arnd@kernel.org>,
        "linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>
CC:     Arnd Bergmann <arnd@arndb.de>,
        Christoph Hellwig <hch@infradead.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Andrew Morton <akpm@linux-foundation.org>,
        Borislav Petkov <bp@alien8.de>,
        Brian Gerst <brgerst@gmail.com>,
        Eric Biederman <ebiederm@xmission.com>,
        Ingo Molnar <mingo@kernel.org>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Linux-MM <linux-mm@kvack.org>,
        "kexec@lists.infradead.org" <kexec@lists.infradead.org>
Subject: RE: [PATCH v3 2/4] mm: simplify compat_sys_move_pages
Thread-Topic: [PATCH v3 2/4] mm: simplify compat_sys_move_pages
Thread-Index: AQHXS1wYCu76VfkYCU+t8Sv5x7/YH6rpt7nQ
Date:   Tue, 18 May 2021 20:49:34 +0000
Message-ID: <f52b8bc9600443dab1814766552fe6bf@AcuMS.aculab.com>
References: <20210517203343.3941777-1-arnd@kernel.org>
 <20210517203343.3941777-3-arnd@kernel.org>
In-Reply-To: <20210517203343.3941777-3-arnd@kernel.org>
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From: Arnd Bergmann
> Sent: 17 May 2021 21:34
> 
> The compat move_pages() implementation uses compat_alloc_user_space()
> for converting the pointer array. Moving the compat handling into
> the function itself is a bit simpler and lets us avoid the
> compat_alloc_user_space() call.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  mm/migrate.c | 45 ++++++++++++++++++++++++++++++---------------
>  1 file changed, 30 insertions(+), 15 deletions(-)
> 
> diff --git a/mm/migrate.c b/mm/migrate.c
> index b234c3f3acb7..a68d07f19a1a 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -1855,6 +1855,23 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages,
>  	mmap_read_unlock(mm);
>  }
> 
> +static int put_compat_pages_array(const void __user *chunk_pages[],
> +				  const void __user * __user *pages,
> +				  unsigned long chunk_nr)
> +{

Should that be get_compat_pages_array() ?

	David

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