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, 73 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/tsc2004.c b/drivers/input/touchscreen/tsc2004.c
new file mode 100644
index 000000000..130aeb735
--- /dev/null
+++ b/drivers/input/touchscreen/tsc2004.c
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * TSC2004 touchscreen driver
+ *
+ * Copyright (C) 2015 QWERTY Embedded Design
+ * Copyright (C) 2015 EMAC Inc.
+ */
+
+#include <linux/module.h>
+#include <linux/input.h>
+#include <linux/of.h>
+#include <linux/i2c.h>
+#include <linux/regmap.h>
+#include "tsc200x-core.h"
+
+static const struct input_id tsc2004_input_id = {
+	.bustype = BUS_I2C,
+	.product = 2004,
+};
+
+static int tsc2004_cmd(struct device *dev, u8 cmd)
+{
+	u8 tx = TSC200X_CMD | TSC200X_CMD_12BIT | cmd;
+	s32 data;
+	struct i2c_client *i2c = to_i2c_client(dev);
+
+	data = i2c_smbus_write_byte(i2c, tx);
+	if (data < 0) {
+		dev_err(dev, "%s: failed, command: %x i2c error: %d\n",
+			__func__, cmd, data);
+		return data;
+	}
+
+	return 0;
+}
+
+static int tsc2004_probe(struct i2c_client *i2c)
+
+{
+	return tsc200x_probe(&i2c->dev, i2c->irq, &tsc2004_input_id,
+			     devm_regmap_init_i2c(i2c, &tsc200x_regmap_config),
+			     tsc2004_cmd);
+}
+
+static const struct i2c_device_id tsc2004_idtable[] = {
+	{ .name = "tsc2004" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, tsc2004_idtable);
+
+#ifdef CONFIG_OF
+static const struct of_device_id tsc2004_of_match[] = {
+	{ .compatible = "ti,tsc2004" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, tsc2004_of_match);
+#endif
+
+static struct i2c_driver tsc2004_driver = {
+	.driver = {
+		.name		= "tsc2004",
+		.dev_groups	= tsc200x_groups,
+		.of_match_table	= of_match_ptr(tsc2004_of_match),
+		.pm		= pm_sleep_ptr(&tsc200x_pm_ops),
+	},
+	.id_table       = tsc2004_idtable,
+	.probe          = tsc2004_probe,
+};
+module_i2c_driver(tsc2004_driver);
+
+MODULE_AUTHOR("Michael Welling <mwelling@ieee.org>");
+MODULE_DESCRIPTION("TSC2004 Touchscreen Driver");
+MODULE_LICENSE("GPL");