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_map_pages() is the API which could be used to map kernel memory/pages in drivers which has considered vm_pgoff. vm_map_pages_zero() 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_map_pages_zero() to behave according to the normal vm_pgoff offsetting simply by removing the _zero suffix on the function name and if that causes regressions, it gives us an easy way to revert. Tested on Rockchip hardware and display is working fine, including talking to Lima via prime. 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_map_pages() could be used instead of vm_map_pages_zero(). v2 -> v3: Corrected the documentation as per review comment. As suggested in v2, renaming the interfaces to - *vm_insert_range() -> vm_map_pages()* and *vm_insert_range_buggy() -> vm_map_pages_zero()*. As the interface is renamed, modified the code accordingly, updated the change logs and modified the subject lines to use the new interfaces. There is no other change apart from renaming and using the new interface. Patch[1/9] & [4/9], Tested on Rockchip hardware. v3 -> v4: Fixed build warnings on patch [8/9] reported by kbuild test robot. Souptick Joarder (9): mm: Introduce new vm_map_pages() and vm_map_pages_zero() API arm: mm: dma-mapping: Convert to use vm_map_pages() drivers/firewire/core-iso.c: Convert to use vm_map_pages_zero() drm/rockchip/rockchip_drm_gem.c: Convert to use vm_map_pages() drm/xen/xen_drm_front_gem.c: Convert to use vm_map_pages() iommu/dma-iommu.c: Convert to use vm_map_pages() videobuf2/videobuf2-dma-sg.c: Convert to use vm_map_pages() xen/gntdev.c: Convert to use vm_map_pages() xen/privcmd-buf.c: Convert to use vm_map_pages_zero() 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 | 11 ++- drivers/xen/privcmd-buf.c | 8 +-- include/linux/mm.h | 4 ++ mm/memory.c | 81 ++++++++++++++++++++++ mm/nommu.c | 14 ++++ 13 files changed, 134 insertions(+), 103 deletions(-) -- 1.9.1 _______________________________________________ iommu mailing list email@example.com https://lists.linuxfoundation.org/mailman/listinfo/iommu