linux-kernel - Re: [EXT] Re: [PATCH] media: videobuf2-dma-sg: limit the sg segment size

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAAFQd5Aq=ZrNGQU6psXJXt1ak2SkoRrZ=QBzp+xxHmWre0zBVg@mail.gmail.com>
Date:   Tue, 12 Sep 2023 16:51:43 +0900
From:   Tomasz Figa <tfiga@...omium.org>
To:     Hui Fang <hui.fang@....com>
Cc:     Anle Pan <anle.pan@....com>,
        "m.szyprowski@...sung.com" <m.szyprowski@...sung.com>,
        "mchehab@...nel.org" <mchehab@...nel.org>,
        "linux-media@...r.kernel.org" <linux-media@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Jindong Yue <jindong.yue@....com>,
        Xuegang Liu <xuegang.liu@....com>, Xu Yang <xu.yang_2@....com>
Subject: Re: [EXT] Re: [PATCH] media: videobuf2-dma-sg: limit the sg segment size

On Tue, Sep 12, 2023 at 4:43 PM Hui Fang <hui.fang@....com> wrote:
>
> On Tue, Sep 12, 2023 at 4:11 PM Tomasz Figa <tfiga@...omium.org> wrote:
> > Is your DMA device restricted only to the bottom-most 4 GB (32-bit DMA
> > address)? If yes, would it make sense to also allocate from that area rather
> > than bouncing the memory?
>
> The DMA device use 32-bit DMA address.
> From user space, can't control the v4l2 buffer address, may still change the
> code of vb2_dma_sg_alloc().

Right. You may want to try modifying vb2_dma_sg_alloc_compacted() to
use dma_alloc_pages() instead of alloc_pages().

Best regards,
Tomasz