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Message-ID: <CAFqt6zYxCxzGjv3ea+dYQHcmt2P849ZgaVSH=b05m9P4=MTBEA@mail.gmail.com>
Date: Thu, 17 Jan 2019 17:09:43 +0530
From: Souptick Joarder <jrdr.linux@...il.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
Matthew Wilcox <willy@...radead.org>,
Michal Hocko <mhocko@...e.com>,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
vbabka@...e.cz, Rik van Riel <riel@...riel.com>,
Stephen Rothwell <sfr@...b.auug.org.au>,
rppt@...ux.vnet.ibm.com, Peter Zijlstra <peterz@...radead.org>,
Russell King - ARM Linux <linux@...linux.org.uk>,
robin.murphy@....com, iamjoonsoo.kim@....com, treding@...dia.com,
Kees Cook <keescook@...omium.org>,
Marek Szyprowski <m.szyprowski@...sung.com>,
stefanr@...6.in-berlin.de, hjc@...k-chips.com,
Heiko Stuebner <heiko@...ech.de>, airlied@...ux.ie,
oleksandr_andrushchenko@...m.com, joro@...tes.org,
pawel@...iak.com, Kyungmin Park <kyungmin.park@...sung.com>,
mchehab@...nel.org, Boris Ostrovsky <boris.ostrovsky@...cle.com>,
Juergen Gross <jgross@...e.com>
Cc: linux-kernel@...r.kernel.org, Linux-MM <linux-mm@...ck.org>,
linux-arm-kernel@...ts.infradead.org,
linux1394-devel@...ts.sourceforge.net,
dri-devel@...ts.freedesktop.org,
linux-rockchip@...ts.infradead.org, xen-devel@...ts.xen.org,
iommu@...ts.linux-foundation.org, linux-media@...r.kernel.org
Subject: Re: [PATCH 0/9] Use vm_insert_range and vm_insert_range_buggy
On Fri, Jan 11, 2019 at 8:31 PM Souptick Joarder <jrdr.linux@...il.com> wrote:
>
> Previouly drivers have their own way of mapping range of
> kernel pages/memory into user vma and this was done by
> invoking vm_insert_page() within a loop.
>
> As this pattern is common across different drivers, it can
> be generalized by creating new functions and use it across
> the drivers.
>
> vm_insert_range() is the API which could be used to mapped
> kernel memory/pages in drivers which has considered vm_pgoff
>
> vm_insert_range_buggy() is the API which could be used to map
> range of kernel memory/pages in drivers which has not considered
> vm_pgoff. vm_pgoff is passed default as 0 for those drivers.
>
> We _could_ then at a later "fix" these drivers which are using
> vm_insert_range_buggy() to behave according to the normal vm_pgoff
> offsetting simply by removing the _buggy suffix on the function
> name and if that causes regressions, it gives us an easy way to revert.
>
> There is an existing bug in [7/9], where user passed length is not
> verified against object_count. For any value of length > object_count
> it will end up overrun page array which could lead to a potential bug.
> This is fixed as part of these conversion.
>
> Souptick Joarder (9):
> mm: Introduce new vm_insert_range and vm_insert_range_buggy API
> arch/arm/mm/dma-mapping.c: Convert to use vm_insert_range
> drivers/firewire/core-iso.c: Convert to use vm_insert_range_buggy
> drm/rockchip/rockchip_drm_gem.c: Convert to use vm_insert_range
> drm/xen/xen_drm_front_gem.c: Convert to use vm_insert_range
> iommu/dma-iommu.c: Convert to use vm_insert_range
> videobuf2/videobuf2-dma-sg.c: Convert to use vm_insert_range_buggy
> xen/gntdev.c: Convert to use vm_insert_range
> xen/privcmd-buf.c: Convert to use vm_insert_range_buggy
Any further comment on these patches ?
>
> arch/arm/mm/dma-mapping.c | 22 ++----
> drivers/firewire/core-iso.c | 15 +----
> drivers/gpu/drm/rockchip/rockchip_drm_gem.c | 17 +----
> drivers/gpu/drm/xen/xen_drm_front_gem.c | 18 ++---
> drivers/iommu/dma-iommu.c | 12 +---
> drivers/media/common/videobuf2/videobuf2-dma-sg.c | 22 ++----
> drivers/xen/gntdev.c | 16 ++---
> drivers/xen/privcmd-buf.c | 8 +--
> include/linux/mm.h | 4 ++
> mm/memory.c | 81 +++++++++++++++++++++++
> mm/nommu.c | 14 ++++
> 11 files changed, 129 insertions(+), 100 deletions(-)
>
> --
> 1.9.1
>
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