[PATCH 0/9] Use vm_insert_range and vm_insert_range_buggy

[PATCH 0/9] Use vm_insert_range and vm_insert_range_buggy

[Souptick Joarder]

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

 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

Re: [PATCH 0/9] Use vm_insert_range and vm_insert_range_buggy

[Souptick Joarder]

On Fri, Jan 11, 2019 at 8:31 PM Souptick Joarder <jrdr.linux@gmail.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
>