8a695a5873
include/linux/mmzone.h describes ARCH_HAS_HOLES_MEMORYMODEL as relevant when parts the memmap have been free()d. This would happen on systems where memory is smaller than a sparsemem-section, and the extra struct pages are expensive. pfn_valid() on these systems returns true for the whole sparsemem-section, so an extra memmap_valid_within() check is needed. On arm64 we have nomap memory, so always provide pfn_valid() to test for nomap pages. This means ARCH_HAS_HOLES_MEMORYMODEL's extra checks are already rolled up into pfn_valid(). Remove it. Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.