KVM: Don't pre-reserve xarray entries when storing empty/NULL attributesgrafted

Skip the xarray reservation loop when clearing all memory attributes, as
storing NULL only erases the entry and never needs to allocate, so no
reservation (and no cleanup of a failed one) is required in that case.

Suggested-by: Sean Christopherson <seanjc@google.com>
Cc: David Ballesteros <davimaba.v@proton.me>
Signed-off-by: Zeng Chi <zengchi@kylinos.cn>
Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com
[sean: split to separate patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>

1 files changed, 67 insertions, 0 deletions

diff --git a/Documentation/userspace-api/media/index.rst b/Documentation/userspace-api/media/index.rst
new file mode 100644
index 000000000..337ef6c7c
--- /dev/null
+++ b/Documentation/userspace-api/media/index.rst
@@ -0,0 +1,67 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+.. include:: <isonum.txt>
+
+########################################
+Linux Media Infrastructure userspace API
+########################################
+
+This section contains the  driver development information and Kernel APIs
+used by media devices.
+
+Please see:
+
+Documentation/admin-guide/media/index.rst
+
+  - for usage information about media subsystem and supported drivers;
+
+Documentation/driver-api/media/index.rst
+
+  - for driver development information and Kernel APIs used by
+    media devices;
+
+
+.. toctree::
+    :caption: Table of Contents
+    :maxdepth: 1
+
+    intro
+    v4l/v4l2
+    dvb/dvbapi
+    rc/remote_controllers
+    mediactl/media-controller
+    cec/cec-api
+    gen-errors
+
+    glossary
+
+    fdl-appendix
+
+    drivers/index
+
+**Copyright** |copy| 2009-2020 : LinuxTV Developers
+
+::
+
+  Permission is granted to copy, distribute and/or modify this document
+  under the terms of the GNU Free Documentation License, Version 1.1 or
+  any later version published by the Free Software Foundation, with no
+  Invariant Sections. A copy of the license is included in the chapter
+  entitled "GNU Free Documentation License".
+
+Please notice that some documents inside the media userspace API,
+when explicitly mentioned on its source code, are dual-licensed
+with GNU Free Documentation License  Version 1.1 and with the
+GNU General Public License::
+
+  This documentation is free software; you can redistribute it and/or modify it
+  under the terms of the GNU General Public License as published by the Free
+  Software Foundation; either version 2 of the License, or (at your option) any
+  later version.
+
+  This program is distributed in the hope that it will be useful, but WITHOUT
+  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+  FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+  more details.
+
+  For more details see the file COPYING in the source distribution of Linux.