linux-toradex.git/include/linux/highmem.h, branch v6.0-rc7

highmem: delete a sentence from kmap_local_page() kdocs

2022-08-09T01:06:46+00:00

kmap_local_page() should always be preferred in place of kmap() and
kmap_atomic().  "Only use when really necessary." is not consistent with
the Documentation/mm/highmem.rst and these kdocs it embeds.

Therefore, delete the above-mentioned sentence from kdocs.

Link: https://lkml.kernel.org/r/20220728154844.10874-7-fmdefrancesco@gmail.com
Signed-off-by: Fabio M. De Francesco 
Suggested-by: Ira Weiny 
Reviewed-by: Ira Weiny 
Cc: Matthew Wilcox (Oracle) 
Cc: Mike Rapoport 
Cc: Sebastian Andrzej Siewior 
Cc: Thomas Gleixner 
Cc: Catalin Marinas 
Cc: Jonathan Corbet 
Cc: Peter Collingbourne 
Cc: Vlastimil Babka 
Cc: Will Deacon 
Signed-off-by: Andrew Morton

highmem: specify that kmap_local_page() is callable from interrupts

2022-08-09T01:06:45+00:00

In a recent thread about converting kmap() to kmap_local_page(), the
safety of calling kmap_local_page() was questioned.[1]

"any context" should probably be enough detail for users who want to know
whether or not kmap_local_page() can be called from interrupts.  However,
Linux still has kmap_atomic() which might make users think they must use
the latter in interrupts.

Add "including interrupts" for better clarity.

[1] https://lore.kernel.org/lkml/3187836.aeNJFYEL58@opensuse/

Link: https://lkml.kernel.org/r/20220728154844.10874-3-fmdefrancesco@gmail.com
Signed-off-by: Fabio M. De Francesco 
Suggested-by: Ira Weiny 
Cc: Matthew Wilcox (Oracle) 
Cc: Mike Rapoport 
Cc: Sebastian Andrzej Siewior 
Cc: Thomas Gleixner 
Cc: Catalin Marinas 
Cc: Jonathan Corbet 
Cc: Peter Collingbourne 
Cc: Vlastimil Babka 
Cc: Will Deacon 
Signed-off-by: Andrew Morton

highmem: remove unneeded spaces in kmap_local_page() kdocs

2022-08-09T01:06:45+00:00

Patch series "highmem: Extend kmap_local_page() documentation", v2.

The Highmem interface is evolving and the current documentation does not
reflect the intended uses of each of the calls.  Furthermore, after a
recent series of reworks, the differences of the calls can still be
confusing and may lead to the expanded use of calls which are deprecated.

This series is the second round of changes towards an enhanced
documentation of the Highmem's interface; at this stage the patches are
only focused to kmap_local_page().

In addition it also contains some minor clean ups.


This patch (of 7):

In the kdocs of kmap_local_page(), the description of @page starts after
several unnecessary spaces.

Therefore, remove those spaces.

Link: https://lkml.kernel.org/r/20220728154844.10874-1-fmdefrancesco@gmail.com
Link: https://lkml.kernel.org/r/20220728154844.10874-2-fmdefrancesco@gmail.com
Signed-off-by: Fabio M. De Francesco 
Suggested-by: Ira Weiny 
Reviewed-by: Ira Weiny 
Cc: Matthew Wilcox (Oracle) 
Cc: Mike Rapoport 
Cc: Sebastian Andrzej Siewior 
Cc: Thomas Gleixner 
Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: Peter Collingbourne 
Cc: Vlastimil Babka 
Cc: Jonathan Corbet 
Signed-off-by: Andrew Morton

Merge tag 'mm-stable-2022-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2022-08-05T23:32:45+00:00

Pull MM updates from Andrew Morton:
 "Most of the MM queue. A few things are still pending.

  Liam's maple tree rework didn't make it. This has resulted in a few
  other minor patch series being held over for next time.

  Multi-gen LRU still isn't merged as we were waiting for mapletree to
  stabilize. The current plan is to merge MGLRU into -mm soon and to
  later reintroduce mapletree, with a view to hopefully getting both
  into 6.1-rc1.

  Summary:

   - The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe
     Lin, Yang Shi, Anshuman Khandual and Mike Rapoport

   - Some kmemleak fixes from Patrick Wang and Waiman Long

   - DAMON updates from SeongJae Park

   - memcg debug/visibility work from Roman Gushchin

   - vmalloc speedup from Uladzislau Rezki

   - more folio conversion work from Matthew Wilcox

   - enhancements for coherent device memory mapping from Alex Sierra

   - addition of shared pages tracking and CoW support for fsdax, from
     Shiyang Ruan

   - hugetlb optimizations from Mike Kravetz

   - Mel Gorman has contributed some pagealloc changes to improve
     latency and realtime behaviour.

   - mprotect soft-dirty checking has been improved by Peter Xu

   - Many other singleton patches all over the place"

 [ XFS merge from hell as per Darrick Wong in

   https://lore.kernel.org/all/YshKnxb4VwXycPO8@magnolia/ ]

* tag 'mm-stable-2022-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (282 commits)
  tools/testing/selftests/vm/hmm-tests.c: fix build
  mm: Kconfig: fix typo
  mm: memory-failure: convert to pr_fmt()
  mm: use is_zone_movable_page() helper
  hugetlbfs: fix inaccurate comment in hugetlbfs_statfs()
  hugetlbfs: cleanup some comments in inode.c
  hugetlbfs: remove unneeded header file
  hugetlbfs: remove unneeded hugetlbfs_ops forward declaration
  hugetlbfs: use helper macro SZ_1{K,M}
  mm: cleanup is_highmem()
  mm/hmm: add a test for cross device private faults
  selftests: add soft-dirty into run_vmtests.sh
  selftests: soft-dirty: add test for mprotect
  mm/mprotect: fix soft-dirty check in can_change_pte_writable()
  mm: memcontrol: fix potential oom_lock recursion deadlock
  mm/gup.c: fix formatting in check_and_migrate_movable_page()
  xfs: fail dax mount if reflink is enabled on a partition
  mm/memcontrol.c: remove the redundant updating of stats_flush_threshold
  userfaultfd: don't fail on unrecognized features
  hugetlb_cgroup: fix wrong hugetlb cgroup numa stat
  ...

mm: introduce clear_highpage_kasan_tagged

2022-07-04T01:08:39+00:00

Add a clear_highpage_kasan_tagged() helper that does clear_highpage() on a
page potentially tagged by KASAN.

This helper is used by the following patch.

Link: https://lkml.kernel.org/r/4471979b46b2c487787ddcd08b9dc5fedd1b6ffd.1654798516.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov 
Cc: Alexander Potapenko 
Cc: Andrey Ryabinin 
Cc: Dmitry Vyukov 
Cc: Marco Elver 
Signed-off-by: Andrew Morton

Documentation: highmem: use literal block for code example in highmem.h comment

2022-07-03T22:42:32+00:00

When building htmldocs on Linus's tree, there are inline emphasis warnings
on include/linux/highmem.h:

Documentation/vm/highmem:166: ./include/linux/highmem.h:154: WARNING: Inline emphasis start-string without end-string.
Documentation/vm/highmem:166: ./include/linux/highmem.h:157: WARNING: Inline emphasis start-string without end-string.

These warnings above are due to comments in code example at the mentioned
lines above are enclosed by double dash (--), which confuses Sphinx as
inline markup delimiters instead.

Fix these warnings by indenting the code example with literal block
indentation and making the comments C comments.

Link: https://lkml.kernel.org/r/20220622084546.17745-1-bagasdotme@gmail.com
Fixes: 85a85e7601263f ("Documentation/vm: move "Using kmap-atomic" to highmem.h")
Signed-off-by: Bagas Sanjaya 
Reviewed-by: Ira Weiny 
Tested-by: Ira Weiny 
Cc: "Matthew Wilcox (Oracle)" 
Cc: "Fabio M. De Francesco" 
Cc: Sebastian Andrzej Siewior 
Signed-off-by: Andrew Morton

mm/highmem: delete memmove_page()

2022-06-17T02:48:29+00:00

Matthew Wilcox reported that, while he was looking at memmove_page(), he
realized that it can't actually work.

The reasons are hidden in its implementation, which makes use of memmove()
on logical addresses provided by kmap_local_page().  memmove() does the
wrong thing when it tests "if (dest <= src)".

Therefore, delete memmove_page().

No need to change any other code because we have no call sites of
memmove_page() across the whole kernel.

Link: https://lkml.kernel.org/r/20220606141533.555-1-fmdefrancesco@gmail.com
Signed-off-by: Fabio M. De Francesco 
Reported-by: Matthew Wilcox 
Reviewed-by: Baoquan He 
Reviewed-by: Ira Weiny 
Cc: Sebastian Andrzej Siewior 
Signed-off-by: Andrew Morton

Documentation/vm: move "Using kmap-atomic" to highmem.h

2022-05-13T23:48:55+00:00

The use of kmap_atomic() is new code is being deprecated in favor of
kmap_local_page().  For this reason the "Using kmap_atomic" section in
highmem.rst is obsolete and unnecessary, but it can still help developers
if it were moved to kdocs in highmem.h.

Therefore, move the relevant parts of this section from highmem.rst and
merge them with the kdocs in highmem.h.

Link: https://lkml.kernel.org/r/20220428212455.892-4-fmdefrancesco@gmail.com
Signed-off-by: Fabio M. De Francesco 
Suggested-by: Ira Weiny 
Reviewed-by: Sebastian Andrzej Siewior 
Reviewed-by: Ira Weiny 
Cc: Jonathan Corbet 
Cc: Matthew Wilcox 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Catalin Marinas 
Cc: Mike Rapoport 
Cc: Peter Collingbourne 
Cc: Vlastimil Babka 
Cc: Will Deacon 
Cc: Jonathan Corbet 
Signed-off-by: Andrew Morton

mm/highmem: fix kernel-doc warnings in highmem*.h

2022-05-13T23:48:55+00:00

Patch series "Extend and reorganize Highmem's documentation", v4.

This series has the purpose to extend and reorganize Highmem's
documentation.

This is a work in progress because some information should still be moved
from highmem.rst to highmem.h and highmem-internal.h.  Specifically I'm
talking about moving the "how to" information to the relevant headers, as
it as been suggested by Ira Weiny (Intel).

Also, this is a work in progress because some kdocs in highmem.h and
highmem-internal.h should be improved.


This patch (of 4):

`scripts/kernel-doc -v -none include/linux/highmem*` reports the following
warnings:

include/linux/highmem.h:160: warning: expecting prototype for kunmap_atomic(). Prototype was for nr_free_highpages() instead
include/linux/highmem.h:204: warning: No description found for return value of 'alloc_zeroed_user_highpage_movable'
include/linux/highmem-internal.h:256: warning: Function parameter or member '__addr' not described in 'kunmap_atomic'
include/linux/highmem-internal.h:256: warning: Excess function parameter 'addr' description in 'kunmap_atomic'

Fix these warnings by (1) moving the kernel-doc comments from highmem.h to
highmem-internal.h (which is the file were the kunmap_atomic() macro is
actually defined), (2) extending and merging it with the comment which was
already in highmem-internal.h, and (3) using correct parameter names (4)
correcting a few technical inaccuracies in comments, and (5) adding a
deprecation notice in kunmap_atomic() for consistency with kmap_atomic().

Link: https://lkml.kernel.org/r/20220428212455.892-1-fmdefrancesco@gmail.com
Link: https://lkml.kernel.org/r/20220428212455.892-2-fmdefrancesco@gmail.com
Signed-off-by: Fabio M. De Francesco 
Reviewed-by: Sebastian Andrzej Siewior 
Reviewed-by: Ira Weiny 
Cc: Matthew Wilcox 
Cc: Mike Rapoport 
Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: Peter Collingbourne 
Cc: Vlastimil Babka 
Cc: Jonathan Corbet 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Jonathan Corbet 
Signed-off-by: Andrew Morton

mm/highmem: VM_BUG_ON() if offset + len > PAGE_SIZE

2022-05-13T14:20:06+00:00

Add VM_BUG_ON() bounds checking to make sure that, if "offset + len>
PAGE_SIZE", memset() does not corrupt data in adjacent pages.

Mainly to match all the similar functions in highmem.h.

Link: https://lkml.kernel.org/r/20220426193020.8710-1-fmdefrancesco@gmail.com
Signed-off-by: Fabio M. De Francesco 
Reviewed-by: Andrew Morton 
Cc: Ira Weiny 
Cc: Catalin Marinas 
Cc: "Matthew Wilcox (Oracle)" 
Cc: Peter Collingbourne 
Signed-off-by: Andrew Morton