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maple_tree: add mas_next_range() and mas_find_range() interfaces
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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/20230512182036.359030-29-Liam.Howlett@oracle.com
Signed-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>
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@howlett @akpm00
howlett authored and akpm00 committed May 13, 2023
1 parent 55ee5b5 commit 0335e08
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Showing 2 changed files with 137 additions and 50 deletions.
15 changes: 15 additions & 0 deletions include/linux/maple_tree.h
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Original file line number Diff line number Diff line change
Expand Up @@ -455,6 +455,7 @@ void *mas_erase(struct ma_state *mas);
int mas_store_gfp(struct ma_state *mas, void *entry, gfp_t gfp);
void mas_store_prealloc(struct ma_state *mas, void *entry);
void *mas_find(struct ma_state *mas, unsigned long max);
void *mas_find_range(struct ma_state *mas, unsigned long max);
void *mas_find_rev(struct ma_state *mas, unsigned long min);
int mas_preallocate(struct ma_state *mas, gfp_t gfp);
bool mas_is_err(struct ma_state *mas);
Expand All @@ -467,6 +468,7 @@ int mas_expected_entries(struct ma_state *mas, unsigned long nr_entries);

void *mas_prev(struct ma_state *mas, unsigned long min);
void *mas_next(struct ma_state *mas, unsigned long max);
void *mas_next_range(struct ma_state *mas, unsigned long max);

int mas_empty_area(struct ma_state *mas, unsigned long min, unsigned long max,
unsigned long size);
Expand Down Expand Up @@ -528,6 +530,19 @@ static inline void mas_reset(struct ma_state *mas)
#define mas_for_each(__mas, __entry, __max) \
while (((__entry) = mas_find((__mas), (__max))) != NULL)

/**
* mas_contiguous() - Iterate over a contiguous range of the maple tree.
* @__mas: Maple Tree operation state (maple_state)
* @__entry: Entry retrieved from the tree
* @__max: maximum index to retrieve from the tree
*
* When returned, mas->index and mas->last will hold the entire range of the
* entry. The loop will terminate on the first NULL encountered.
*
* Note: may return the zero entry.
*/
#define mas_contiguous(__mas, __entry, __max) \
while (((__entry) = mas_find_range((__mas), (__max))) != NULL)

/**
* mas_set_range() - Set up Maple Tree operation state for a different index.
Expand Down
172 changes: 122 additions & 50 deletions lib/maple_tree.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4793,13 +4793,10 @@ static void *mas_next_slot(struct ma_state *mas, unsigned long max, bool empty)
*/
static inline void *mas_next_entry(struct ma_state *mas, unsigned long limit)
{
void *entry = NULL;

if (mas->last >= limit)
return NULL;

entry = mas_next_slot(mas, limit, false);
return entry;
return mas_next_slot(mas, limit, false);
}

/*
Expand Down Expand Up @@ -5880,43 +5877,80 @@ int mas_expected_entries(struct ma_state *mas, unsigned long nr_entries)
}
EXPORT_SYMBOL_GPL(mas_expected_entries);

/**
* mas_next() - Get the next entry.
* @mas: The maple state
* @max: The maximum index to check.
*
* Returns the next entry after @mas->index.
* Must hold rcu_read_lock or the write lock.
* Can return the zero entry.
*
* Return: The next entry or %NULL
*/
void *mas_next(struct ma_state *mas, unsigned long max)
static inline bool mas_next_setup(struct ma_state *mas, unsigned long max,
void **entry)
{
bool was_none = mas_is_none(mas);

if (mas_is_none(mas) || mas_is_paused(mas))
mas->node = MAS_START;

if (mas_is_start(mas))
mas_walk(mas); /* Retries on dead nodes handled by mas_walk */
*entry = mas_walk(mas); /* Retries on dead nodes handled by mas_walk */

if (mas_is_ptr(mas)) {
*entry = NULL;
if (was_none && mas->index == 0) {
mas->index = mas->last = 0;
return mas_root(mas);
return true;
}
mas->index = 1;
mas->last = ULONG_MAX;
mas->node = MAS_NONE;
return NULL;
return true;
}

/* Retries on dead nodes handled by mas_next_entry */
return mas_next_entry(mas, max);
if (mas_is_none(mas))
return true;
return false;
}

/**
* mas_next() - Get the next entry.
* @mas: The maple state
* @max: The maximum index to check.
*
* Returns the next entry after @mas->index.
* Must hold rcu_read_lock or the write lock.
* Can return the zero entry.
*
* Return: The next entry or %NULL
*/
void *mas_next(struct ma_state *mas, unsigned long max)
{
void *entry = NULL;

if (mas_next_setup(mas, max, &entry))
return entry;

/* Retries on dead nodes handled by mas_next_slot */
return mas_next_slot(mas, max, false);
}
EXPORT_SYMBOL_GPL(mas_next);

/**
* mas_next_range() - Advance the maple state to the next range
* @mas: The maple state
* @max: The maximum index to check.
*
* Sets @mas->index and @mas->last to the range.
* Must hold rcu_read_lock or the write lock.
* Can return the zero entry.
*
* Return: The next entry or %NULL
*/
void *mas_next_range(struct ma_state *mas, unsigned long max)
{
void *entry = NULL;

if (mas_next_setup(mas, max, &entry))
return entry;

/* Retries on dead nodes handled by mas_next_slot */
return mas_next_slot(mas, max, true);
}
EXPORT_SYMBOL_GPL(mas_next_range);

/**
* mt_next() - get the next value in the maple tree
* @mt: The maple tree
Expand Down Expand Up @@ -6026,73 +6060,111 @@ void mas_pause(struct ma_state *mas)
EXPORT_SYMBOL_GPL(mas_pause);

/**
* mas_find() - On the first call, find the entry at or after mas->index up to
* %max. Otherwise, find the entry after mas->index.
* mas_find_setup() - Internal function to set up mas_find*().
* @mas: The maple state
* @max: The maximum value to check.
*
* Must hold rcu_read_lock or the write lock.
* If an entry exists, last and index are updated accordingly.
* May set @mas->node to MAS_NONE.
* @max: The maximum index
* @entry: Pointer to the entry
*
* Return: The entry or %NULL.
* Returns: True if entry is the answer, false otherwise.
*/
void *mas_find(struct ma_state *mas, unsigned long max)
static inline bool mas_find_setup(struct ma_state *mas, unsigned long max,
void **entry)
{
*entry = NULL;

if (unlikely(mas_is_none(mas))) {
if (unlikely(mas->last >= max))
return NULL;
return true;

mas->index = mas->last;
mas->node = MAS_START;
}

if (unlikely(mas_is_paused(mas))) {
} else if (unlikely(mas_is_paused(mas))) {
if (unlikely(mas->last >= max))
return NULL;
return true;

mas->node = MAS_START;
mas->index = ++mas->last;
}


if (unlikely(mas_is_ptr(mas)))
} else if (unlikely(mas_is_ptr(mas)))
goto ptr_out_of_range;

if (unlikely(mas_is_start(mas))) {
/* First run or continue */
void *entry;

if (mas->index > max)
return NULL;
return true;

entry = mas_walk(mas);
if (entry)
return entry;
*entry = mas_walk(mas);
if (*entry)
return true;

}

if (unlikely(!mas_searchable(mas))) {
if (unlikely(mas_is_ptr(mas)))
goto ptr_out_of_range;

return NULL;
return true;
}

if (mas->index == max)
return NULL;
return true;

/* Retries on dead nodes handled by mas_next_slot */
return mas_next_slot(mas, max, false);
return false;

ptr_out_of_range:
mas->node = MAS_NONE;
mas->index = 1;
mas->last = ULONG_MAX;
return NULL;
return true;
}

/**
* mas_find() - On the first call, find the entry at or after mas->index up to
* %max. Otherwise, find the entry after mas->index.
* @mas: The maple state
* @max: The maximum value to check.
*
* Must hold rcu_read_lock or the write lock.
* If an entry exists, last and index are updated accordingly.
* May set @mas->node to MAS_NONE.
*
* Return: The entry or %NULL.
*/
void *mas_find(struct ma_state *mas, unsigned long max)
{
void *entry = NULL;

if (mas_find_setup(mas, max, &entry))
return entry;

/* Retries on dead nodes handled by mas_next_slot */
return mas_next_slot(mas, max, false);
}
EXPORT_SYMBOL_GPL(mas_find);

/**
* mas_find_range() - On the first call, find the entry at or after
* mas->index up to %max. Otherwise, advance to the next slot mas->index.
* @mas: The maple state
* @max: The maximum value to check.
*
* Must hold rcu_read_lock or the write lock.
* If an entry exists, last and index are updated accordingly.
* May set @mas->node to MAS_NONE.
*
* Return: The entry or %NULL.
*/
void *mas_find_range(struct ma_state *mas, unsigned long max)
{
void *entry;

if (mas_find_setup(mas, max, &entry))
return entry;

/* Retries on dead nodes handled by mas_next_slot */
return mas_next_slot(mas, max, true);
}
EXPORT_SYMBOL_GPL(mas_find_range);

/**
* mas_find_rev: On the first call, find the first non-null entry at or below
* mas->index down to %min. Otherwise find the first non-null entry below
Expand Down

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