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Howlett" , Alice Ryhl , Andrew Ballance , Jonathan Corbet , Shuah Khan , Wei-Lin Chang Subject: [RFC PATCH 1/2] Documentation: maple_tree: Point out constraint when using xa_{mk, to}_value Date: Sat, 18 Apr 2026 21:47:53 +0100 Message-ID: <20260418204754.120405-2-weilin.chang@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260418204754.120405-1-weilin.chang@arm.com> References: <20260418204754.120405-1-weilin.chang@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam10 X-Stat-Signature: be9f6udb6waj4he46dmqx6b17b1a1xk8 X-Rspam-User: X-Rspamd-Queue-Id: 400DC4000A X-HE-Tag: 1776545397-613698 X-HE-Meta: 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 vwec2evA 1aYTSJ6nz4mM6sVJPAqTC2Vl01pXi7ohiY/dQwGgDAdiMrOEdykbPtWPHoUJbJS0h+7p6pEkq6gCTUNwMJhIwmc6ZeVKOAMw6hReEhUfpyw2uuRoZLsLm+UMxAcpncV9vMBqVxjJ3p0eX5C3jVlpBCoTOUHvNL/UWkm3WYhekD6nM0j/BU44e/W5CGBrcYB1ubb8HfvJyUMfLgX/UIltyNSNHxviKeeL+1/f3U3YHoSjYw1SZAR2C8CGAo0VzVvbwlGNnVBH9/kyXz7fZ5OEWcWXRl8N6XmQaqE5b Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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 --- Documentation/core-api/maple_tree.rst | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/Documentation/core-api/maple_tree.rst b/Documentation/core-api/maple_tree.rst index ccdd1615cf97..15eda6742af8 100644 --- a/Documentation/core-api/maple_tree.rst +++ b/Documentation/core-api/maple_tree.rst @@ -28,10 +28,11 @@ virtual memory areas. 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 -:ref:`maple-tree-advanced-api`, but are blocked by the normal API. +entries under the condition that their top bits are never 1, then the user 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 :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 size (or larger). -- 2.43.0