The watermark check in compaction_zonelist_suitable(), called from
should_compact_retry(), is sandwiched between two watermark checks
already: before, there are freelist attempts as part of direct reclaim and
direct compaction; after, there is a last-minute freelist attempt in
__alloc_pages_may_oom().

The check in compaction_zonelist_suitable() isn't necessary. Kill it.

Link: https://lkml.kernel.org/r/20230519123959.77335-6-hannes@cmpxchg.orgSigned-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Remove from all paths not reachable via /proc/sys/vm/compact_memory.

Link: https://lkml.kernel.org/r/20230519123959.77335-5-hannes@cmpxchg.orgSigned-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

__compaction_suitable() is supposed to check for available migration
targets.  However, it also checks whether the operation was requested via
/proc/sys/vm/compact_memory, and whether the original allocation request
can already succeed.  These don't apply to all callsites.

Move the checks out to the callers, so that later patches can deal with
them one by one.  No functional change intended.

[hannes@cmpxchg.org: fix comment, per Vlastimil]
  Link: https://lkml.kernel.org/r/20230602144942.GC161817@cmpxchg.org
Link: https://lkml.kernel.org/r/20230519123959.77335-4-hannes@cmpxchg.orgSigned-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

The different branches for retry are unnecessarily complicated.  There are
really only three outcomes: progress (retry n times), skipped (retry if
reclaim can help), failed (retry with higher priority).

Rearrange the branches and the retry counter to make it simpler.

[hannes@cmpxchg.org: restore behavior when hitting max_retries]
  Link: https://lkml.kernel.org/r/20230602144705.GB161817@cmpxchg.org
Link: https://lkml.kernel.org/r/20230519123959.77335-3-hannes@cmpxchg.orgSigned-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Patch series "mm: compaction: cleanups & simplifications".

These compaction cleanups are split out from the huge page allocator
series[1], as requested by reviewer feedback.

[1] https://lore.kernel.org/linux-mm/20230418191313.268131-1-hannes@cmpxchg.org/


This patch (of 5):

The compaction result helpers encode quirks that are specific to the
allocator's retry logic.  E.g.  COMPACT_SUCCESS and COMPACT_COMPLETE
actually represent failures that should be retried upon, and so on.  I
frequently found myself pulling up the helper implementation in order to
understand and work on the retry logic.  They're not quite clean
abstractions; rather they split the retry logic into two locations.

Remove the helpers and inline the checks.  Then comment on the result
interpretations directly where the decision making happens.

Link: https://lkml.kernel.org/r/20230519123959.77335-1-hannes@cmpxchg.org
Link: https://lkml.kernel.org/r/20230519123959.77335-2-hannes@cmpxchg.orgSigned-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

smatch reports
mm/page_alloc.c:247:5: warning: symbol
  'sysctl_lowmem_reserve_ratio' was not declared. Should it be static?

This variable is only used in its defining file, so it should be static

Link: https://lkml.kernel.org/r/20230518141119.927074-1-trix@redhat.comSigned-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

If the iterator has moved to the previous entry, then step forward one
range, back to the gap.

Link: https://lkml.kernel.org/r/20230518145544.1722059-36-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Add functionality to the VMA iterator to advance and retreat one offset
within the maple tree, regardless of the value contained.  This can lead
to less re-walking to find an area of interest, especially when there is
nothing in that offset.

Link: https://lkml.kernel.org/r/20230518145544.1722059-35-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Now that the functions have changed the limits, update the testing of the
maple tree to test these new settings.

Link: https://lkml.kernel.org/r/20230518145544.1722059-34-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

When there is a single entry tree (range of 0-0 pointing to an entry),
then ensure the limit is either 0-0 or 1-oo, depending on where the user
walks.  Ensure the correct node setting as well; either MAS_ROOT or
MAS_NONE.

Link: https://lkml.kernel.org/r/20230518145544.1722059-33-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Some users of the maple tree may want to move to the previous range
regardless of the value stored there.  Add this interface as well as the
'find' variant to support walking to the first value, then iterating over
the previous ranges.

Link: https://lkml.kernel.org/r/20230518145544.1722059-32-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Sometimes the user needs to revert to the previous slot, regardless of if
it is empty or not.  Add an interface to go to the previous slot.

Since there can't be two consecutive NULLs in the tree, the mas_prev()
function can be implemented by calling mas_prev_slot() a maximum of 2
times.  Change the underlying interface to use mas_prev_slot() to align
the code.

Link: https://lkml.kernel.org/r/20230518145544.1722059-31-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

These functions need to move for future use.

Link: https://lkml.kernel.org/r/20230518145544.1722059-30-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Some users of the maple tree may want to move to the next range in the
tree, even if it stores a NULL.  This family of function provides that
functionality by advancing one slot at a time and returning the result,
while mas_contiguous() will iterate over the range and stop on
encountering the first NULL.

Link: https://lkml.kernel.org/r/20230518145544.1722059-29-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Sometimes, during a tree walk, the user needs the next slot regardless of
if it is empty or not.  Add an interface to get the next slot.

Since there are no consecutive NULLs allowed in the tree, the mas_next()
function can only advance two slots at most.  So use the new
mas_next_slot() interface to align both implementations.  Use this method
for mas_find() as well.

Link: https://lkml.kernel.org/r/20230518145544.1722059-28-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Empty area will return -EINVAL if the search window is smaller than the
requested size.  Fix the test case to check for this error code.

Link: https://lkml.kernel.org/r/20230518145544.1722059-27-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Since the maple tree is inclusive in range, ensure that a range of 1 (min
= max) works for searching for a gap in either direction, and make sure
the size is at least 1 but not larger than the delta between min and max.

This commit also updates the testing.  Unfortunately there isn't a way to
safely update the tests and code without a test failure.

Link: https://lkml.kernel.org/r/20230518145544.1722059-26-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Suggested-by: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Keep a reference to the node when possible with mas_prev().  This will
avoid re-walking the tree.  In keeping a reference to the node, keep the
last/index accurate to the range being referenced.  This means the limit
may be within the range, but the range may extend outside of the limit.

Also fix the single entry tree to respect the range (of 0), or set the
node to MAS_NONE in the case of shifting beyond 0.

Link: https://lkml.kernel.org/r/20230518145544.1722059-25-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Clean up the mas_next() call to try and keep a node reference when
possible.  This will avoid re-walking the tree in most cases.

Also clean up the single entry tree handling to ensure index/last are
consistent with what one would expect.  (returning NULL with limit of
1-oo).

Link: https://lkml.kernel.org/r/20230518145544.1722059-24-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

The maple tree iterator clean up is incompatible with the way
do_vmi_align_munmap() expects it to behave.  Update the expected behaviour
to map now since the change will work currently.

Link: https://lkml.kernel.org/r/20230518145544.1722059-23-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

When a dead node is detected, the depth has already been set to 1 so reset
it to 0.

Link: https://lkml.kernel.org/r/20230518145544.1722059-22-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mas_destroy currently checks if mas->node is MAS_START prior to calling
mas_start(), but this is unnecessary as mas_start() will do nothing if the
node is anything but MAS_START.

Link: https://lkml.kernel.org/r/20230518145544.1722059-21-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

The test functions are not needed after the module is removed, so mark
them as such.  Add __exit to the module removal function.  Some other
variables have been marked as const static as well.

Link: https://lkml.kernel.org/r/20230518145544.1722059-20-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

MAS_WARN_ON() will provide more information on the maple state and can be
more useful for debugging.  Use this version of WARN_ON() in the debugging
code when storing to the tree.

Update the printk to a pr_warn(), but this will only be printed when maple
tree debug is enabled anyways.

Making all print statements into one will keep them together on a busy
terminal.

Link: https://lkml.kernel.org/r/20230518145544.1722059-19-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Use the vma iterator in the validation code and combine the code to check
the maple tree into the main validate_mm() function.

Introduce a new function vma_iter_dump_tree() to dump the maple tree in
hex layout.

Replace all calls to validate_mm_mt() with validate_mm().

[Liam.Howlett@oracle.com: update validate_mm() to use vma iterator CONFIG flag]
  Link: https://lkml.kernel.org/r/20230606183538.588190-1-Liam.Howlett@oracle.com
Link: https://lkml.kernel.org/r/20230518145544.1722059-18-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

The test code is less useful without debug, but can still do general
validations.  Define mt_dump(), mas_dump() and mas_wr_dump() as a noop if
debug is not enabled and document it in the test module information that
more information can be obtained with another kernel config option.

MT_BUG_ON() will report a failures without tree dumps, and the output will
be less useful.

Link: https://lkml.kernel.org/r/20230518145544.1722059-17-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Rename mte_pivots() to mas_pivots() and pass through the ma_state to set
the error code to -EIO when the offset is out of range for the node type. 
Change the WARN_ON() to MAS_WARN_ON() to log the maple state.

Link: https://lkml.kernel.org/r/20230518145544.1722059-16-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Replace the call to BUG_ON() in mas_meta_gap() with calls before the
function call MAS_BUG_ON() to get more information on error condition.

Link: https://lkml.kernel.org/r/20230518145544.1722059-15-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mas_store_prealloc() should never fail, but if it does due to internal
tree issues then get as much debug information as possible prior to
crashing the kernel.

Link: https://lkml.kernel.org/r/20230518145544.1722059-14-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

In the even of trying to remove data from a leaf node by use of
mas_topiary_range(), log the maple state.

Link: https://lkml.kernel.org/r/20230518145544.1722059-13-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Use MAS_BUG_ON() instead of MT_BUG_ON() to get the maple state
information.  In the unlikely event of a tree height of > 31, try to
increase the probability of useful information being logged.

Link: https://lkml.kernel.org/r/20230518145544.1722059-12-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Use MAS_BUG_ON() to dump the maple state and tree in the unlikely event of
an issue.

Link: https://lkml.kernel.org/r/20230518145544.1722059-11-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Using MT_WARN_ON() allows for the removal of if statements before logging.
Using MAS_WARN_ON() will provide more information when issues are
encountered.

Link: https://lkml.kernel.org/r/20230518145544.1722059-10-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

If RCU is enabled and the tree isn't locked, just warn the user and avoid
crashing the kernel.

Link: https://lkml.kernel.org/r/20230518145544.1722059-9-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Use MT_BUG_ON() to get more information when running with MAPLE_TREE_DEBUG
enabled.

Link: https://lkml.kernel.org/r/20230518145544.1722059-8-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Add debug macros to dump the maple state and/or the tree for both warning
and bug_on calls.

Link: https://lkml.kernel.org/r/20230518145544.1722059-7-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Allow different formatting strings to be used when dumping the tree. 
Currently supports hex and decimal.

Link: https://lkml.kernel.org/r/20230518145544.1722059-6-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Convert loop type to ensure all variables are set to make the compiler
happy, and use the mas_is_none() function instead of explicitly checking
the node in the maple state.

Link: https://lkml.kernel.org/r/20230518145544.1722059-5-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

The maple tree node limits are implied by the parent.  When walking up the
tree, the limit may not be known until a slot that does not have implied
limits are encountered.  However, if the node is the left-most or
right-most node, the walking up to find that limit can be skipped.

This commit also fixes the debug/testing code that was not setting the
limit on walking down the tree as that optimization is not compatible with
this change.

Link: https://lkml.kernel.org/r/20230518145544.1722059-4-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mas_parent_enum() is a simple wrapper for mte_parent_enum() which is only
called from that wrapper.  Remove the wrapper and inline mte_parent_enum()
into mas_parent_enum().

At the same time, clean up the bit masking of the root pointer since it
cannot be set by the time the bit masking occurs.  Change the check on the
root bit to a WARN_ON(), and fix the verification code to not trigger the
WARN_ON() before checking if the node is root.

Align the name to mas_parent_type() since mas_node_type() exists already.

Link: https://lkml.kernel.org/r/20230518145544.1722059-3-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>