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, 33 insertions, 0 deletions

diff --git a/include/uapi/mtd/mtd-user.h b/include/uapi/mtd/mtd-user.h
new file mode 100644
index 000000000..7eca1b3f6
--- /dev/null
+++ b/include/uapi/mtd/mtd-user.h
@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
+/*
+ * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
+ *
+ * This program 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#ifndef __MTD_USER_H__
+#define __MTD_USER_H__
+
+/* This file is blessed for inclusion by userspace */
+#include <mtd/mtd-abi.h>
+
+typedef struct mtd_info_user mtd_info_t;
+typedef struct erase_info_user erase_info_t;
+typedef struct region_info_user region_info_t;
+typedef struct nand_oobinfo nand_oobinfo_t;
+typedef struct nand_ecclayout_user nand_ecclayout_t;
+
+#endif /* __MTD_USER_H__ */