linux-kernel - Re: [PATCH v2 03/20] x86/mm: temporary mm struct

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Message-ID: <20190204142829.GD29639@zn.tnic>
Date:   Mon, 4 Feb 2019 15:28:29 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Nadav Amit <namit@...are.com>
Cc:     Rick Edgecombe <rick.p.edgecombe@...el.com>,
        Andy Lutomirski <luto@...nel.org>,
        Ingo Molnar <mingo@...hat.com>,
        LKML <linux-kernel@...r.kernel.org>, X86 ML <x86@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Damian Tometzki <linux_dti@...oud.com>,
        linux-integrity <linux-integrity@...r.kernel.org>,
        LSM List <linux-security-module@...r.kernel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Kernel Hardening <kernel-hardening@...ts.openwall.com>,
        Linux-MM <linux-mm@...ck.org>, Will Deacon <will.deacon@....com>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        Kristen Carlson Accardi <kristen@...ux.intel.com>,
        "Dock, Deneen T" <deneen.t.dock@...el.com>,
        Kees Cook <keescook@...omium.org>,
        Dave Hansen <dave.hansen@...el.com>
Subject: Re: [PATCH v2 03/20] x86/mm: temporary mm struct

On Thu, Jan 31, 2019 at 10:19:54PM +0000, Nadav Amit wrote:
> Having a different struct can prevent the misuse of using mm_structs in
> unuse_temporary_mm() that were not “used” using use_temporary_mm. The
> typedef, I presume, can deter users from starting to play with the internal
> “private” fields.

Ok, makes sense.

> > That prev.prev below looks unnecessary, instead of just using prev.
> > 
> >> +	struct mm_struct *prev;
> > 
> > Why "prev”?
> 
> This is obviously the previous active mm. Feel free to suggest an
> alternative name.

Well, when I look at the typedef I'm wondering why is it called "prev"
but I guess this is to mean that it will be saving the previously used
mm, so ack.

Thx.

-- 
Regards/Gruss,
    Boris.

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