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Date:   Mon, 10 Oct 2022 09:42:34 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     Sumit Garg <sumit.garg@linaro.org>,
        Phil Chang =?utf-8?B?KOW8teS4luWLsyk=?= 
        <Phil.Chang@mediatek.com>,
        "ira.weiny@intel.com" <ira.weiny@intel.com>,
        Jens Wiklander <jens.wiklander@linaro.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Al Viro <viro@zeniv.linux.org.uk>,
        "Fabio M. De Francesco" <fmdefrancesco@gmail.com>,
        Christoph Hellwig <hch@lst.de>,
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        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
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Subject: Re: [PATCH 2/4] tee: Remove vmalloc page support
Message-ID: <20221010074234.GA20788@lst.de>
References: <20221002002326.946620-1-ira.weiny@intel.com> <20221002002326.946620-3-ira.weiny@intel.com> <CAFA6WYOGT1sJLA4c_B88NaXgxv4fm-idi5QMYvXdXB0acCF3sw@mail.gmail.com> <TYZPR03MB65279558CC22F5130B710EA8FB5D9@TYZPR03MB6527.apcprd03.prod.outlook.com> <CAFA6WYMT9S1Di6DN_UXc823f0ZTkqerE1PB=oG6wmfx28vEbDg@mail.gmail.com> <CAHk-=whVyH-wSWLd=Zn4rwo+91T+qzRvfMPC2yFX98GxykOqOw@mail.gmail.com>
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On Thu, Oct 06, 2022 at 11:20:16AM -0700, Linus Torvalds wrote:
> Actually, I think even then we shouldn't support vmalloc - and
> register_shm_helper() just needs to be changed to pass in an array of
> actual page pointers instead.
> 
> At that point TEE_SHM_USER_MAPPED should also go away, because then
> it's the caller that should just do either the user space page
> pinning, or pass in the kernel page pointer.
> 
> JensW, is there some reason that wouldn't work?

I suspect the best long term option would be to just pass an iov_iter..