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, 87 insertions, 0 deletions

diff --git a/drivers/mfd/lp873x.c b/drivers/mfd/lp873x.c
new file mode 100644
index 000000000..d2c90302b
--- /dev/null
+++ b/drivers/mfd/lp873x.c
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2016 Texas Instruments Incorporated - https://www.ti.com/
+ *
+ * Author: Keerthy <j-keerthy@ti.com>
+ */
+
+#include <linux/interrupt.h>
+#include <linux/mfd/core.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#include <linux/mfd/lp873x.h>
+
+static const struct regmap_config lp873x_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = LP873X_REG_MAX,
+};
+
+static const struct mfd_cell lp873x_cells[] = {
+	{ .name = "lp873x-regulator", },
+	{ .name = "lp873x-gpio", },
+};
+
+static int lp873x_probe(struct i2c_client *client)
+{
+	struct lp873x *lp873;
+	int ret;
+	unsigned int otpid;
+
+	lp873 = devm_kzalloc(&client->dev, sizeof(*lp873), GFP_KERNEL);
+	if (!lp873)
+		return -ENOMEM;
+
+	lp873->dev = &client->dev;
+
+	lp873->regmap = devm_regmap_init_i2c(client, &lp873x_regmap_config);
+	if (IS_ERR(lp873->regmap)) {
+		ret = PTR_ERR(lp873->regmap);
+		dev_err(lp873->dev,
+			"Failed to initialize register map: %d\n", ret);
+		return ret;
+	}
+
+	ret = regmap_read(lp873->regmap, LP873X_REG_OTP_REV, &otpid);
+	if (ret) {
+		dev_err(lp873->dev, "Failed to read OTP ID\n");
+		return ret;
+	}
+
+	lp873->rev = otpid & LP873X_OTP_REV_OTP_ID;
+
+	i2c_set_clientdata(client, lp873);
+
+	ret = mfd_add_devices(lp873->dev, PLATFORM_DEVID_AUTO, lp873x_cells,
+			      ARRAY_SIZE(lp873x_cells), NULL, 0, NULL);
+
+	return ret;
+}
+
+static const struct of_device_id of_lp873x_match_table[] = {
+	{ .compatible = "ti,lp8733", },
+	{ .compatible = "ti,lp8732", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, of_lp873x_match_table);
+
+static const struct i2c_device_id lp873x_id_table[] = {
+	{ "lp873x" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, lp873x_id_table);
+
+static struct i2c_driver lp873x_driver = {
+	.driver	= {
+		.name	= "lp873x",
+		.of_match_table = of_lp873x_match_table,
+	},
+	.probe		= lp873x_probe,
+	.id_table	= lp873x_id_table,
+};
+module_i2c_driver(lp873x_driver);
+
+MODULE_AUTHOR("J Keerthy <j-keerthy@ti.com>");
+MODULE_DESCRIPTION("LP873X chip family Multi-Function Device driver");
+MODULE_LICENSE("GPL v2");