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Mike Rapoport
51c656aef6
Patch series "arm64: drop pfn_valid_within() and simplify pfn_valid()", v4. These patches aim to remove CONFIG_HOLES_IN_ZONE and essentially hardwire pfn_valid_within() to 1. The idea is to mark NOMAP pages as reserved in the memory map and restore the intended semantics of pfn_valid() to designate availability of struct page for a pfn. With this the core mm will be able to cope with the fact that it cannot use NOMAP pages and the holes created by NOMAP ranges within MAX_ORDER blocks will be treated correctly even without the need for pfn_valid_within. This patch (of 4): Add comment describing the semantics of pfn_valid() that clarifies that pfn_valid() only checks for availability of a memory map entry (i.e. struct page) for a PFN rather than availability of usable memory backing that PFN. The most "generic" version of pfn_valid() used by the configurations with SPARSEMEM enabled resides in include/linux/mmzone.h so this is the most suitable place for documentation about semantics of pfn_valid(). Link: https://lkml.kernel.org/r/[email protected] Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Mike Rapoport <[email protected]> Suggested-by: Anshuman Khandual <[email protected]> Reviewed-by: Anshuman Khandual <[email protected]> Acked-by: Ard Biesheuvel <[email protected]> Reviewed-by: Kefeng Wang <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: David Hildenbrand <[email protected]> Cc: Marc Zyngier <[email protected]> Cc: Mark Rutland <[email protected]> Cc: Mike Rapoport <[email protected]> Cc: Will Deacon <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>