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arm64: drop pfn_valid_within() and simplify pfn_valid()
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The arm64's version of pfn_valid() differs from the generic because of two
reasons:

* Parts of the memory map are freed during boot. This makes it necessary to
  verify that there is actual physical memory that corresponds to a pfn
  which is done by querying memblock.

* There are NOMAP memory regions. These regions are not mapped in the
  linear map and until the previous commit the struct pages representing
  these areas had default values.

As the consequence of absence of the special treatment of NOMAP regions in
the memory map it was necessary to use memblock_is_map_memory() in
pfn_valid() and to have pfn_valid_within() aliased to pfn_valid() so that
generic mm functionality would not treat a NOMAP page as a normal page.

Since the NOMAP regions are now marked as PageReserved(), pfn walkers and
the rest of core mm will treat them as unusable memory and thus
pfn_valid_within() is no longer required at all and can be disabled on
arm64.

pfn_valid() can be slightly simplified by replacing
memblock_is_map_memory() with memblock_is_memory().

[[email protected]: fix merge fix]
  Link: https://lkml.kernel.org/r/[email protected]

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Mike Rapoport <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Acked-by: Ard Biesheuvel <[email protected]>
Reviewed-by: Kefeng Wang <[email protected]>
Cc: Anshuman Khandual <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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rppt authored and torvalds committed Jul 1, 2021
1 parent 873ba46 commit a7d9f30
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Showing 2 changed files with 1 addition and 2 deletions.
1 change: 0 additions & 1 deletion arch/arm64/Kconfig
Original file line number Diff line number Diff line change
Expand Up @@ -201,7 +201,6 @@ config ARM64
select HAVE_KPROBES
select HAVE_KRETPROBES
select HAVE_GENERIC_VDSO
select HOLES_IN_ZONE
select IOMMU_DMA if IOMMU_SUPPORT
select IRQ_DOMAIN
select IRQ_FORCED_THREADING
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2 changes: 1 addition & 1 deletion arch/arm64/mm/init.c
Original file line number Diff line number Diff line change
Expand Up @@ -252,7 +252,7 @@ int pfn_valid(unsigned long pfn)
if (!early_section(ms))
return pfn_section_valid(ms, pfn);

return memblock_is_map_memory(addr);
return memblock_is_memory(addr);
}
EXPORT_SYMBOL(pfn_valid);

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