linux-kernel - RE: [PATCH v3 2/4] mm: simplify compat_sys_move

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Date:   Tue, 18 May 2021 20:49:34 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Arnd Bergmann' <arnd@...nel.org>,
        "linux-arch@...r.kernel.org" <linux-arch@...r.kernel.org>
CC:     Arnd Bergmann <arnd@...db.de>,
        Christoph Hellwig <hch@...radead.org>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Borislav Petkov <bp@...en8.de>,
        Brian Gerst <brgerst@...il.com>,
        Eric Biederman <ebiederm@...ssion.com>,
        Ingo Molnar <mingo@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Linux-MM <linux-mm@...ck.org>,
        "kexec@...ts.infradead.org" <kexec@...ts.infradead.org>
Subject: RE: [PATCH v3 2/4] mm: simplify compat_sys_move_pages

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@...db.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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