How to map physical pages into vma

[Boris Bierbaum <boris@lfbs.RWTH-Aachen.DE>]

Hi,

inside of a kernel module, I need to re-map a part of a processes'
virtual address space (usually from the heap) to a range of physically
contiguous page frames that another kernel module provides me with (I
get a kernel virtual address to the beginning of the first page frame).

I tried remap_pfn_range(), but as Copy-on-Write is used for the heap's
vma, remap_pfn_range() refuses to do the mapping, because I only want to
re-map some part of the vma, not the whole thing.

Then I tried to use vm_insert_page() for each individual physical page,
but as the count is 0 for these pages, this is refused, too.

I can't use split_vma() to split the heap's vma twice and then use
remap_pfn_range() for the vma that represents the part that is to be
re-mapped, because split_vma() isn't supposed to be called from inside a
module, right?

Is there anything I can do about this?

Thanks in advance
Boris


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