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David Hildenbrand b0f86aaebe fs/dax: use vmf_insert_folio_pmd() to insert the huge zero folio
Let's convert to vmf_insert_folio_pmd().

There is a theoretical change in behavior: in the unlikely case there is
already something mapped, we'll now still call trace_dax_pmd_load_hole()
and return VM_FAULT_NOPAGE.

Previously, we would have returned VM_FAULT_FALLBACK, and the caller would
have zapped the PMD to try a PTE fault.

However, that behavior was different to other PTE+PMD faults, when there
would already be something mapped, and it's not even clear if it could be
triggered.

Assuming the huge zero folio is already mapped, all good, no need to
fallback to PTEs.

Assuming there is already a leaf page table ...  the behavior would be
just like when trying to insert a PMD mapping a folio through
dax_fault_iter()->vmf_insert_folio_pmd().

Assuming there is already something else mapped as PMD?  It sounds like a
BUG, and the behavior would be just like when trying to insert a PMD
mapping a folio through dax_fault_iter()->vmf_insert_folio_pmd().

So, it sounds reasonable to not handle huge zero folios differently to
inserting PMDs mapping folios when there already is something mapped.

Link: https://lkml.kernel.org/r/20250811112631.759341-5-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Juegren Gross <jgross@suse.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
History 2025-09-13 16:54:51 -07:00
arch treewide: remove MIGRATEPAGE_SUCCESS 2025-09-13 16:54:50 -07:00
block block: validate QoS before calling __rq_qos_done_bio() 2025-08-26 10:34:08 -06:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto Significant patch series in this pull request: 2025-08-03 16:23:09 -07:00
Documentation docs/mm/damon/design: fix typo: s/sz_trtied/sz_tried/ 2025-09-13 16:54:49 -07:00
drivers treewide: remove MIGRATEPAGE_SUCCESS 2025-09-13 16:54:50 -07:00
fs fs/dax: use vmf_insert_folio_pmd() to insert the huge zero folio 2025-09-13 16:54:51 -07:00
include treewide: remove MIGRATEPAGE_SUCCESS 2025-09-13 16:54:50 -07:00
init hardening: Require clang 20.1.0 for __counted_by 2025-08-29 12:04:53 -07:00
io_uring io_uring/kbuf: always use READ_ONCE() to read ring provided buffer lengths 2025-08-28 05:48:34 -06:00
ipc vfs-6.17-rc1.mmap_prepare 2025-07-28 13:43:25 -07:00
kernel mm: replace (20 - PAGE_SHIFT) with common macros for pages<->MB conversion 2025-09-13 16:54:42 -07:00
lib xarray: remove redundant __GFP_NOWARN 2025-09-13 16:54:46 -07:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm mm/huge_memory: support huge zero folio in vmf_insert_folio_pmd() 2025-09-13 16:54:51 -07:00
net net: ipv4: fix regression in local-broadcast routes 2025-08-28 10:52:30 +02:00
rust rust: support large alignments in allocations 2025-09-13 16:54:46 -07:00
samples Significant patch series in this pull request: 2025-08-03 16:23:09 -07:00
scripts kasan: fix GCC mem-intrinsic prefix with sw tags 2025-08-27 22:45:43 -07:00
security + Features 2025-08-04 08:17:28 -07:00
sound ALSA: hda/hdmi: Add pin fix for another HP EliteDesk 800 G4 model 2025-09-01 13:51:57 +02:00
tools selftests/proc: test PROCMAP_QUERY ioctl while vma is concurrently modified 2025-09-13 16:54:48 -07:00
usr usr/include: openrisc: don't HDRTEST bpf_perf_event.h 2025-05-12 15:03:17 +09:00
virt Merge tag 'kvm-x86-no_assignment-6.17' of https://github.com/kvm-x86/linux into HEAD 2025-07-29 08:36:42 -04:00
.clang-format Linux 6.15-rc5 2025-05-06 16:39:25 +10:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore gitignore: allow .pylintrc to be tracked 2025-07-02 17:10:04 -06:00
.mailmap .mailmap: add entry for Easwar Hariharan 2025-08-19 16:35:55 -07:00
.pylintrc docs: add a .pylintrc file with sys path for docs scripts 2025-04-09 12:10:33 -06:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: retire Boris from TLS maintainers 2025-08-26 17:36:01 -07:00
Kbuild drm: ensure drm headers are self-contained and pass kernel-doc 2025-02-12 10:44:43 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS gpio fixes for v6.17-rc4 2025-08-31 08:49:55 -07:00
Makefile Linux 6.17-rc4 2025-08-31 15:33:07 -07:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

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 reStructuredText markup notation.

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.