maple_tree: document that "last" in mtree_insert_range() is inclusive

The kernel doc of mtree_insert_range() does not state if the address
represented by the "last" parameter is inclusive or exclusive.  This can
lead to bugs by code that assumes it is exclusive.  Explicitly state that
the parameter is inclusive.

Link: https://lore.kernel.org/20260512175623.4c5ca8d2@gandalf.local.home
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Reviewed-by: "Liam R. Howlett" <liam@infradead.org>
Acked-by: SeongJae Park <sj@kernel.org>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Andrew Ballance <andrewjballance@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 60ae5e6fc1ee69f5d2422c77ff8c9573e85cde26..e52876435b77f07d07c8355688f6bfc19d5d730e 100644 (file)
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -5727,13 +5727,16 @@ int mtree_store(struct maple_tree *mt, unsigned long index, void *entry,
 EXPORT_SYMBOL(mtree_store);
 
 /**
- * mtree_insert_range() - Insert an entry at a given range if there is no value.
+ * mtree_insert_range() - Insert an entry from [first, last] at a given range
+ *                        if there is no value.
  * @mt: The maple tree
  * @first: The start of the range
- * @last: The end of the range
+ * @last: The end of the range (inclusive)
  * @entry: The entry to store
  * @gfp: The GFP_FLAGS to use for allocations.
  *
+ * Note that @last is inclusive. That is, @last = @first + length - 1;
+ *
  * Return: 0 on success, -EEXISTS if the range is occupied, -EINVAL on invalid
  * request, -ENOMEM if memory could not be allocated.
  */