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maple_tree: fix a few documentation issues 

The documentation of mt_next() claims that it starts the search at the
provided index.  That's incorrect as it starts the search after the
provided index.

The documentation of mt_find() is slightly confusing.  "Handles locking"
is not really helpful as it does not explain how the "locking" works. 
Also the documentation of index talks about a range, while in reality the
index is updated on a succesful search to the index of the found entry
plus one.

Fix similar issues for mt_find_after() and mt_prev().

Reword the confusing "Note: Will not return the zero entry." comment on
mt_for_each() and document @__index correctly.

Link: https://lkml.kernel.org/r/87ttw2n556.ffs@tglx
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Shanker Donthineni <sdonthineni@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Thomas Gleixner 2023-05-23 22:51:01 +02:00 committed by Andrew Morton
parent 20c897eadf
commit fad9c80e63
2 changed files with 24 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
include/linux/maple_tree.h
View File

@ -662,10 +662,11 @@ void *mt_next(struct maple_tree *mt, unsigned long index, unsigned long max);
* mt_for_each - Iterate over each entry starting at index until max.
* @__tree: The Maple Tree
* @__entry: The current entry
* @__index: The index to update to track the location in the tree
* @__index: The index to start the search from. Subsequently used as iterator.
* @__max: The maximum limit for @index
*
* Note: Will not return the zero entry.
* This iterator skips all entries, which resolve to a NULL pointer,
* e.g. entries which has been reserved with XA_ZERO_ENTRY.
*/
#define mt_for_each(__tree, __entry, __index, __max) \
for (__entry = mt_find(__tree, &(__index), __max); \

26
lib/maple_tree.c
View File

@ -5750,7 +5750,11 @@ EXPORT_SYMBOL_GPL(mas_next_range);
* @index: The start index
* @max: The maximum index to check
*
* Return: The entry at @index or higher, or %NULL if nothing is found.
* Takes RCU read lock internally to protect the search, which does not
* protect the returned pointer after dropping RCU read lock.
* See also: Documentation/core-api/maple_tree.rst
*
* Return: The entry higher than @index or %NULL if nothing is found.
*/
void *mt_next(struct maple_tree *mt, unsigned long index, unsigned long max)
{
@ -5856,7 +5860,11 @@ EXPORT_SYMBOL_GPL(mas_prev_range);
* @index: The start index
* @min: The minimum index to check
*
* Return: The entry at @index or lower, or %NULL if nothing is found.
* Takes RCU read lock internally to protect the search, which does not
* protect the returned pointer after dropping RCU read lock.
* See also: Documentation/core-api/maple_tree.rst
*
* Return: The entry before @index or %NULL if nothing is found.
*/
void *mt_prev(struct maple_tree *mt, unsigned long index, unsigned long min)
{
@ -6468,9 +6476,15 @@ EXPORT_SYMBOL(mtree_destroy);
* mt_find() - Search from the start up until an entry is found.
* @mt: The maple tree
* @index: Pointer which contains the start location of the search
* @max: The maximum value to check
* @max: The maximum value of the search range
*
* Handles locking. @index will be incremented to one beyond the range.
* Takes RCU read lock internally to protect the search, which does not
* protect the returned pointer after dropping RCU read lock.
* See also: Documentation/core-api/maple_tree.rst
*
* In case that an entry is found @index is updated to point to the next
* possible entry independent whether the found entry is occupying a
* single index or a range if indices.
*
* Return: The entry at or after the @index or %NULL
*/
@ -6528,7 +6542,9 @@ EXPORT_SYMBOL(mt_find);
* @index: Pointer which contains the start location of the search
* @max: The maximum value to check
*
* Handles locking, detects wrapping on index == 0
* Same as mt_find() except that it checks @index for 0 before
* searching. If @index == 0, the search is aborted. This covers a wrap
* around of @index to 0 in an iterator loop.
*
* Return: The entry at or after the @index or %NULL
*/