linux-kernel - Re: remove the ->mapping_error method from dma_map

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <CAHk-=wgfGzXuDAKFQPdzMib3QCRHfSTsy5=gLU-WCoya+Ym+1A@mail.gmail.com>
Date:   Thu, 22 Nov 2018 09:09:47 -0800
From:   Linus Torvalds <torvalds@...ux-foundation.org>
To:     linux@...linux.org.uk
Cc:     Christoph Hellwig <hch@....de>, linux-arch@...r.kernel.org,
        linux-alpha@...r.kernel.org, linux-ia64@...r.kernel.org,
        linux-parisc@...r.kernel.org,
        David Woodhouse <dwmw2@...radead.org>, joro@...tes.org,
        "the arch/x86 maintainers" <x86@...nel.org>,
        Linux List Kernel Mailing <linux-kernel@...r.kernel.org>,
        iommu@...ts.linux-foundation.org, jdmason@...zu.us,
        xen-devel@...ts.xenproject.org, robin.murphy@....com,
        linux-arm-kernel@...ts.infradead.org, m.szyprowski@...sung.com
Subject: Re: remove the ->mapping_error method from dma_map_ops V2

On Thu, Nov 22, 2018 at 9:07 AM Russell King - ARM Linux
<linux@...linux.org.uk> wrote:
>
> I'm afraid that won't work very well - 32 bit platforms with 64-bit
> addresses (LPAE) would have dma_addr_t as a 64-bit value, which
> wouldn't fit into an unsigned long.

Good point. So we'd have to have a special IS_DMA_ERR() function that
takes a dma_addr_t and checks the same "is it the top 4095 values".

Because I'd still prefer to allow people to return the _actual_ error,
and to have "return -Exyz" as the error case. That part still DTRT
even with dma_addr_t.

              Linus