linux-kernel - Re: [PATCH v5 2/2] media: usb: pwc: Don't use coherent DMA buffers for ISO transfer

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: <20181207152502.GA30455@infradead.org>
Date:   Fri, 7 Dec 2018 07:25:02 -0800
From:   Christoph Hellwig <hch@...radead.org>
To:     Laurent Pinchart <laurent.pinchart@...asonboard.com>
Cc:     "Matwey V. Kornilov" <matwey@....msu.ru>,
        linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
        matwey.kornilov@...il.com, tfiga@...omium.org,
        stern@...land.harvard.edu, ezequiel@...labora.com,
        hdegoede@...hat.com, hverkuil@...all.nl, mchehab@...nel.org,
        rostedt@...dmis.org, mingo@...hat.com, isely@...ox.com,
        bhumirks@...il.com, colin.king@...onical.com,
        kieran.bingham@...asonboard.com, keiichiw@...omium.org,
        Christoph Hellwig <hch@...radead.org>
Subject: Re: [PATCH v5 2/2] media: usb: pwc: Don't use coherent DMA buffers
 for ISO transfer

Folks, can you take a look at this tree and see if this is useful
for USB:

http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/dma-noncoherent-allocator

The idea is that you use dma_alloc_attrs with the DMA_ATTR_NON_CONSISTENT
now that I've made sure it is avaiable everywhere [1], and we can use
dma_sync_single_* on it.

The only special case USB will need are the HCD_LOCAL_MEM devices, for
which we must use dma_alloc_coherent (or dma_alloc_attrs without
DMA_ATTR_NON_CONSISTENT) and must skip the dma_sync_single_* calls,
so we'll probably need USB subsystem wrappers for those calls.

[1] except powerpc in this tree - I have another series to make powerpc
use the generic dma noncoherent code, which would cover it.