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.
v1 -> v2: Few Reviewed-by.
Updated the change log in [8/9]
In [7/9], vm_pgoff is treated in V4L2 API as a 'cookie' to select a buffer, not as a in-buffer offset by design and it always want to mmap a whole buffer from its beginning. Added additional changes after discussing with Marek and vm_insert_range could be used instead of vm_insert_range_buggy.
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 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-core.c | 7 ++ .../media/common/videobuf2/videobuf2-dma-contig.c | 6 -- 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 ++++ 13 files changed, 136 insertions(+), 106 deletions(-)