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* [PATCH v2 00/13] mm: add bitmap VMA flag helpers and convert all mmap_prepare to use them
@ 2026-01-22 16:06 Lorenzo Stoakes
  2026-01-22 16:06 ` [PATCH v2 01/13] mm/vma: remove __private sparse decoration from vma_flags_t Lorenzo Stoakes
                   ` (14 more replies)
  0 siblings, 15 replies; 56+ messages in thread
From: Lorenzo Stoakes @ 2026-01-22 16:06 UTC (permalink / raw)
  To: Andrew Morton
  Cc: Jarkko Sakkinen, Dave Hansen, Thomas Gleixner, Ingo Molnar,
	Borislav Petkov, x86, H . Peter Anvin, Arnd Bergmann,
	Greg Kroah-Hartman, Dan Williams, Vishal Verma, Dave Jiang,
	Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
	David Airlie, Simona Vetter, Jani Nikula, Joonas Lahtinen,
	Rodrigo Vivi, Tvrtko Ursulin, Christian Koenig, Huang Rui,
	Matthew Auld, Matthew Brost, Alexander Viro, Christian Brauner,
	Jan Kara, Benjamin LaHaise, Gao Xiang, Chao Yu, Yue Hu,
	Jeffle Xu, Sandeep Dhavale, Hongbo Li, Chunhai Guo,
	Theodore Ts'o, Andreas Dilger, Muchun Song, Oscar Salvador,
	David Hildenbrand, Konstantin Komarov, Mike Marshall,
	Martin Brandenburg, Tony Luck, Reinette Chatre, Dave Martin,
	James Morse, Babu Moger, Carlos Maiolino, Damien Le Moal,
	Naohiro Aota, Johannes Thumshirn, Matthew Wilcox,
	Liam R . Howlett, Vlastimil Babka, Mike Rapoport,
	Suren Baghdasaryan, Michal Hocko, Hugh Dickins, Baolin Wang,
	Zi Yan, Nico Pache, Ryan Roberts, Dev Jain, Barry Song,
	Lance Yang, Jann Horn, Pedro Falcato, David Howells, Paul Moore,
	James Morris, Serge E . Hallyn, Yury Norov, Rasmus Villemoes,
	linux-sgx, linux-kernel, nvdimm, linux-cxl, dri-devel, intel-gfx,
	linux-fsdevel, linux-aio, linux-erofs, linux-ext4, linux-mm,
	ntfs3, devel, linux-xfs, keyrings, linux-security-module,
	Jason Gunthorpe

We introduced the bitmap VMA type vma_flags_t in the aptly named commit
9ea35a25d51b ("mm: introduce VMA flags bitmap type") in order to permit
future growth in VMA flags and to prevent the asinine requirement that VMA
flags be available to 64-bit kernels only if they happened to use a bit
number about 32-bits.

This is a long-term project as there are very many users of VMA flags
within the kernel that need to be updated in order to utilise this new
type.

In order to further this aim, this series adds a number of helper functions
to enable ordinary interactions with VMA flags - that is testing, setting
and clearing them.

In order to make working with VMA bit numbers less cumbersome this series
introduces the mk_vma_flags() helper macro which generates a vma_flags_t
from a variadic parameter list, e.g.:

	vma_flags_t flags = mk_vma_flags(VMA_READ_BIT, VMA_WRITE_BIT,
					 VMA_EXEC_BIT);

It turns out that the compiler optimises this very well to the point that
this is just as efficient as using VM_xxx pre-computed bitmap values.

This series then introduces the following functions:

	bool vma_flags_test_mask(vma_flags_t flags, vma_flags_t to_test);
	bool vma_flags_test_all_mask(vma_flags_t flags, vma_flags_t to_test);
	void vma_flags_set_mask(vma_flags_t *flags, vma_flags_t to_set);
	void vma_flags_clear_mask(vma_flags_t *flags, vma_flags_t to_clear);

Providing means of testing any flag, testing all flags, setting, and clearing a
specific vma_flags_t mask.

For convenience, helper macros are provided - vma_flags_test(),
vma_flags_set() and vma_flags_clear(), each of which utilise mk_vma_flags()
to make these operations easier, as well as an EMPTY_VMA_FLAGS macro to
make initialisation of an empty vma_flags_t value easier, e.g.:

	vma_flags_t flags = EMPTY_VMA_FLAGS;

	vma_flags_set(&flags, VMA_READ_BIT, VMA_WRITE_BIT, VMA_EXEC_BIT);
	...
	if (vma_flags_test(flags, VMA_READ_BIT)) {
		...
	}
	...
	if (vma_flags_test_all_mask(flags, VMA_REMAP_FLAGS)) {
		...
	}
	...
	vma_flags_clear(&flags, VMA_READ_BIT);

Since callers are often dealing with a vm_area_struct (VMA) or vm_area_desc
(VMA descriptor as used in .mmap_prepare) object, this series further
provides helpers for these - firstly vma_set_flags_mask() and vma_set_flags() for a
VMA:

	vma_flags_t flags = EMPTY_VMA_FLAGS:

	vma_flags_set(&flags, VMA_READ_BIT, VMA_WRITE_BIT, VMA_EXEC_BIT);
	...
	vma_set_flags_mask(&vma, flags);
	...
	vma_set_flags(&vma, VMA_DONTDUMP_BIT);

Note that these do NOT ensure appropriate locks are taken and assume the
callers takes care of this.

For VMA descriptors this series adds vma_desc_[test, set,
clear]_flags_mask() and vma_desc_[test, set, clear]_flags() for a VMA
descriptor, e.g.:

	static int foo_mmap_prepare(struct vm_area_desc *desc)
	{
		...
		vma_desc_set_flags(desc, VMA_SEQ_READ_BIT);
		vma_desc_clear_flags(desc, VMA_RAND_READ_BIT);
		...
		if (vma_desc_test_flags(desc, VMA_SHARED_BIT) {
			...
		}
		...
	}

With these helpers introduced, this series then updates all mmap_prepare
users to make use of the vma_flags_t vm_area_desc->vma_flags field rather
than the legacy vm_flags_t vm_area_desc->vm_flags field.

In order to do so, several other related functions need to be updated, with
separate patches for larger changes in hugetlbfs, secretmem and shmem
before finally removing vm_area_desc->vm_flags altogether.

This lays the foundations for future elimination of vm_flags_t and
associated defines and functionality altogether in the long run, and
elimination of the use of vm_flags_t in f_op->mmap() hooks in the near term
as mmap_prepare replaces these.

There is a useful synergy between the VMA flags and mmap_prepare work here
as with this change in place, converting f_op->mmap() to f_op->mmap_prepare
naturally also converts use of vm_flags_t to vma_flags_t in all drivers
which declare mmap handlers.

This accounts for the majority of the users of the legacy vm_flags_*()
helpers and thus a large number of drivers which need to interact with VMA
flags in general.

This series also updates the userland VMA tests to account for the change,
and adds unit tests for these helper functions to assert that they behave
as expected.

In order to faciliate this change in a sensible way, the series also
separates out the VMA unit tests into - code that is duplicated from the
kernel that should be kept in sync, code that is customised for test
purposes and code that is stubbed out.

We also separate out the VMA userland tests into separate files to make it
easier to manage and to provide a sensible baseline for adding the userland
tests for these helpers.


REVIEWS NOTE: I rebased this on
https://lore.kernel.org/linux-mm/cover.1769086312.git.lorenzo.stoakes@oracle.com/
in order to make life easier with conflict resolutions.

v2:
* Rebased on mm-unstable again, and then on my other series :)
* Removed sparse __private decoration - it is not doing us any good, and
  anybody accessing vma->flags.__vma_flags will be very obviously doing
  something wrong (TM) so we don't really need it. This will shut up the
  various bots reporting sparse issues :)
* Made functions which test VMA flags reference a const vma_flags_t *
  pointer for the flags being checked as per Jason.
* Updated entire series to affect this change, including userland tests.
* Fixed missed fixup in memfd_luo_retrieve() and folded into series. Turns
  out this doesn't get built with allmodconfig due to my arch not support.
* Fixed up issue with dev dax reported by Zi (thanks, much appreciated!)

v1 resend:
* Rebased on mm-unstable to fix vma_internal.h conflict tested and confirmed
  working.
https://lore.kernel.org/all/cover.1768857200.git.lorenzo.stoakes@oracle.com/

v1:
https://lore.kernel.org/all/cover.1768834061.git.lorenzo.stoakes@oracle.com/

Lorenzo Stoakes (13):
  mm/vma: remove __private sparse decoration from vma_flags_t
  mm: rename vma_flag_test/set_atomic() to vma_test/set_atomic_flag()
  mm: add mk_vma_flags() bitmap flag macro helper
  tools: bitmap: add missing bitmap_[subset(), andnot()]
  mm: add basic VMA flag operation helper functions
  mm: update hugetlbfs to use VMA flags on mmap_prepare
  mm: update secretmem to use VMA flags on mmap_prepare
  mm: update shmem_[kernel]_file_*() functions to use vma_flags_t
  mm: update all remaining mmap_prepare users to use vma_flags_t
  mm: make vm_area_desc utilise vma_flags_t only
  tools/testing/vma: separate VMA userland tests into separate files
  tools/testing/vma: separate out vma_internal.h into logical headers
  tools/testing/vma: add VMA userland tests for VMA flag functions

 arch/x86/kernel/cpu/sgx/ioctl.c            |    2 +-
 drivers/char/mem.c                         |    6 +-
 drivers/dax/device.c                       |   10 +-
 drivers/gpu/drm/drm_gem.c                  |    5 +-
 drivers/gpu/drm/i915/gem/i915_gem_shmem.c  |    2 +-
 drivers/gpu/drm/i915/gem/i915_gem_ttm.c    |    3 +-
 drivers/gpu/drm/i915/gt/shmem_utils.c      |    3 +-
 drivers/gpu/drm/ttm/tests/ttm_tt_test.c    |    2 +-
 drivers/gpu/drm/ttm/ttm_backup.c           |    3 +-
 drivers/gpu/drm/ttm/ttm_tt.c               |    2 +-
 fs/aio.c                                   |    2 +-
 fs/erofs/data.c                            |    5 +-
 fs/ext4/file.c                             |    4 +-
 fs/hugetlbfs/inode.c                       |   14 +-
 fs/ntfs3/file.c                            |    2 +-
 fs/orangefs/file.c                         |    4 +-
 fs/ramfs/file-nommu.c                      |    2 +-
 fs/resctrl/pseudo_lock.c                   |    2 +-
 fs/romfs/mmap-nommu.c                      |    2 +-
 fs/xfs/scrub/xfile.c                       |    3 +-
 fs/xfs/xfs_buf_mem.c                       |    2 +-
 fs/xfs/xfs_file.c                          |    4 +-
 fs/zonefs/file.c                           |    3 +-
 include/linux/dax.h                        |    8 +-
 include/linux/hugetlb.h                    |    6 +-
 include/linux/hugetlb_inline.h             |   10 +
 include/linux/mm.h                         |  248 ++-
 include/linux/mm_types.h                   |   23 +-
 include/linux/shmem_fs.h                   |    8 +-
 ipc/shm.c                                  |   12 +-
 kernel/relay.c                             |    2 +-
 mm/filemap.c                               |    2 +-
 mm/hugetlb.c                               |   22 +-
 mm/internal.h                              |    2 +-
 mm/khugepaged.c                            |    2 +-
 mm/madvise.c                               |    2 +-
 mm/memfd.c                                 |    6 +-
 mm/memfd_luo.c                             |    2 +-
 mm/memory.c                                |   17 +-
 mm/mmap.c                                  |   10 +-
 mm/mremap.c                                |    2 +-
 mm/secretmem.c                             |    7 +-
 mm/shmem.c                                 |   59 +-
 mm/util.c                                  |    2 +-
 mm/vma.c                                   |   13 +-
 mm/vma.h                                   |    3 +-
 security/keys/big_key.c                    |    2 +-
 tools/include/linux/bitmap.h               |   22 +
 tools/lib/bitmap.c                         |   29 +
 tools/testing/vma/Makefile                 |    7 +-
 tools/testing/vma/include/custom.h         |  119 ++
 tools/testing/vma/include/dup.h            | 1332 ++++++++++++++
 tools/testing/vma/include/stubs.h          |  428 +++++
 tools/testing/vma/main.c                   |   55 +
 tools/testing/vma/shared.c                 |  131 ++
 tools/testing/vma/shared.h                 |  114 ++
 tools/testing/vma/{vma.c => tests/merge.c} |  332 +---
 tools/testing/vma/tests/mmap.c             |   57 +
 tools/testing/vma/tests/vma.c              |  339 ++++
 tools/testing/vma/vma_internal.h           | 1847 +-------------------
 60 files changed, 3055 insertions(+), 2314 deletions(-)
 create mode 100644 tools/testing/vma/include/custom.h
 create mode 100644 tools/testing/vma/include/dup.h
 create mode 100644 tools/testing/vma/include/stubs.h
 create mode 100644 tools/testing/vma/main.c
 create mode 100644 tools/testing/vma/shared.c
 create mode 100644 tools/testing/vma/shared.h
 rename tools/testing/vma/{vma.c => tests/merge.c} (82%)
 create mode 100644 tools/testing/vma/tests/mmap.c
 create mode 100644 tools/testing/vma/tests/vma.c

--
2.52.0


^ permalink raw reply	[flat|nested] 56+ messages in thread

end of thread, other threads:[~2026-02-10 17:46 UTC | newest]

Thread overview: 56+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2026-01-22 16:06 [PATCH v2 00/13] mm: add bitmap VMA flag helpers and convert all mmap_prepare to use them Lorenzo Stoakes
2026-01-22 16:06 ` [PATCH v2 01/13] mm/vma: remove __private sparse decoration from vma_flags_t Lorenzo Stoakes
2026-02-06 17:02   ` Pedro Falcato
2026-02-09 18:38   ` Liam R. Howlett
2026-01-22 16:06 ` [PATCH v2 02/13] mm: rename vma_flag_test/set_atomic() to vma_test/set_atomic_flag() Lorenzo Stoakes
2026-02-06 17:04   ` Pedro Falcato
2026-02-09 18:40   ` Liam R. Howlett
2026-01-22 16:06 ` [PATCH v2 03/13] mm: add mk_vma_flags() bitmap flag macro helper Lorenzo Stoakes
2026-02-06 17:14   ` Pedro Falcato
2026-02-09 14:02     ` Lorenzo Stoakes
2026-02-09 18:44   ` Liam R. Howlett
2026-01-22 16:06 ` [PATCH v2 04/13] tools: bitmap: add missing bitmap_[subset(), andnot()] Lorenzo Stoakes
2026-02-09 18:45   ` Liam R. Howlett
2026-01-22 16:06 ` [PATCH v2 05/13] mm: add basic VMA flag operation helper functions Lorenzo Stoakes
2026-02-06 17:35   ` Pedro Falcato
2026-02-09 14:04     ` Lorenzo Stoakes
2026-02-09 18:53   ` Liam R. Howlett
2026-01-22 16:06 ` [PATCH v2 06/13] mm: update hugetlbfs to use VMA flags on mmap_prepare Lorenzo Stoakes
2026-02-09 19:03   ` Liam R. Howlett
2026-01-22 16:06 ` [PATCH v2 07/13] mm: update secretmem " Lorenzo Stoakes
2026-01-28 12:08   ` Chris Mason
2026-01-28 16:04     ` Lorenzo Stoakes
2026-01-28 16:44   ` Lorenzo Stoakes
2026-02-09 19:06   ` Liam R. Howlett
2026-01-22 16:06 ` [PATCH v2 08/13] mm: update shmem_[kernel]_file_*() functions to use vma_flags_t Lorenzo Stoakes
2026-01-23  6:20   ` Baolin Wang
2026-01-23 12:30     ` Lorenzo Stoakes
2026-01-23  7:46   ` Darrick J. Wong
2026-01-23 12:26     ` Lorenzo Stoakes
2026-01-23 12:33   ` Lorenzo Stoakes
2026-01-25 14:50   ` Jarkko Sakkinen
2026-02-09 19:13   ` Liam R. Howlett
2026-01-22 16:06 ` [PATCH v2 09/13] mm: update all remaining mmap_prepare users " Lorenzo Stoakes
2026-01-22 23:31   ` Damien Le Moal
2026-01-23  7:47   ` Darrick J. Wong
2026-02-06 17:46   ` Pedro Falcato
2026-02-06 19:31     ` Andrew Morton
2026-02-06 20:01       ` Lorenzo Stoakes
2026-02-09 19:27         ` Liam R. Howlett
2026-01-22 16:06 ` [PATCH v2 10/13] mm: make vm_area_desc utilise vma_flags_t only Lorenzo Stoakes
2026-02-06 17:49   ` Pedro Falcato
2026-02-09 19:32   ` Liam R. Howlett
2026-01-22 16:06 ` [PATCH v2 11/13] tools/testing/vma: separate VMA userland tests into separate files Lorenzo Stoakes
2026-02-09 19:58   ` Liam R. Howlett
2026-02-10 17:44     ` Lorenzo Stoakes
2026-01-22 16:06 ` [PATCH v2 12/13] tools/testing/vma: separate out vma_internal.h into logical headers Lorenzo Stoakes
2026-01-27 10:03   ` Lorenzo Stoakes
2026-02-09 20:18   ` Liam R. Howlett
2026-01-22 16:06 ` [PATCH v2 13/13] tools/testing/vma: add VMA userland tests for VMA flag functions Lorenzo Stoakes
2026-02-09 20:23   ` Liam R. Howlett
2026-01-22 16:56 ` [PATCH v2 00/13] mm: add bitmap VMA flag helpers and convert all mmap_prepare to use them Andrew Morton
2026-01-27 13:53 ` Yury Norov
2026-01-27 14:40   ` Lorenzo Stoakes
2026-01-27 21:36     ` Yury Norov
2026-01-28  9:33       ` Lorenzo Stoakes
2026-01-28 15:50         ` Pedro Falcato

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