[PATCH 1/2] Documentation: maple_tree: Point out constraint when using xa_{mk, to}_value

[Wei-Lin Chang]

Using xa_{mk, to}_value when storing values loses the information of
the top bit from the left shift, point that out in the doc.

Signed-off-by: Wei-Lin Chang <weilin.chang at arm.com>
---
 Documentation/core-api/maple_tree.rst | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Documentation/core-api/maple_tree.rst b/Documentation/core-api/maple_tree.rst
index ccdd1615cf97..87020a30ba69 100644
--- a/Documentation/core-api/maple_tree.rst
+++ b/Documentation/core-api/maple_tree.rst
@@ -29,8 +29,9 @@ The Maple Tree can store values between ``0`` and ``ULONG_MAX``.  The Maple
 Tree reserves values with the bottom two bits set to '10' which are below 4096
 (ie 2, 6, 10 .. 4094) for internal use.  If the entries may use reserved
 entries then the users can convert the entries using xa_mk_value() and convert
-them back by calling xa_to_value().  If the user needs to use a reserved
-value, then the user can convert the value when using the
+them back by calling xa_to_value().  Note that xa_{mk, to}_value() bit shifts
+the given data, so the top bit will be lost.  If the user needs to use a
+reserved value, then the user can convert the value when using the
 :ref:`maple-tree-advanced-api`, but are blocked by the normal API.
 
 The Maple Tree can also be configured to support searching for a gap of a given
-- 
2.43.0