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mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-01-12 01:20:14 +00:00
David Hildenbrand 6972706f95 mm/cma: refuse handing out non-contiguous page ranges
Let's disallow handing out PFN ranges with non-contiguous pages, so we can
remove the nth-page usage in __cma_alloc(), and so any callers don't have
to worry about that either when wanting to blindly iterate pages.

This is really only a problem in configs with SPARSEMEM but without
SPARSEMEM_VMEMMAP, and only when we would cross memory sections in some
cases.

Will this cause harm?  Probably not, because it's mostly 32bit that does
not support SPARSEMEM_VMEMMAP.  If this ever becomes a problem we could
look into allocating the memmap for the memory sections spanned by a
single CMA region in one go from memblock.

[david@redhat.com: we can have NUMMU configs with SPARSEMEM enabled]
  Link: https://lkml.kernel.org/r/6ec933b1-b3f7-41c0-95d8-e518bb87375e@redhat.com
Link: https://lkml.kernel.org/r/20250901150359.867252-23-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-09-21 14:22:06 -07:00
2025-07-28 13:43:25 -07:00
2025-08-04 08:17:28 -07:00
2025-05-06 16:39:25 +10:00
2022-09-28 09:02:20 +02:00
2025-02-19 14:53:27 -07:00
2025-09-21 14:21:59 -07:00
2025-08-31 15:33:07 -07:00
2024-03-18 03:36:32 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
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In order to build the documentation, use ``make htmldocs`` or
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There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
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the problems which may result by upgrading your kernel.
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