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, 143 insertions, 0 deletions

diff --git a/drivers/mfd/madera-i2c.c b/drivers/mfd/madera-i2c.c
new file mode 100644
index 000000000..0986e4a99
--- /dev/null
+++ b/drivers/mfd/madera-i2c.c
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * I2C bus interface to Cirrus Logic Madera codecs
+ *
+ * Copyright (C) 2015-2018 Cirrus Logic
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+
+#include <linux/mfd/madera/core.h>
+
+#include "madera.h"
+
+static int madera_i2c_probe(struct i2c_client *i2c)
+{
+	struct madera *madera;
+	const struct regmap_config *regmap_16bit_config = NULL;
+	const struct regmap_config *regmap_32bit_config = NULL;
+	unsigned long type;
+	const char *name;
+	int ret;
+
+	type = (uintptr_t)i2c_get_match_data(i2c);
+	switch (type) {
+	case CS47L15:
+		if (IS_ENABLED(CONFIG_MFD_CS47L15)) {
+			regmap_16bit_config = &cs47l15_16bit_i2c_regmap;
+			regmap_32bit_config = &cs47l15_32bit_i2c_regmap;
+		}
+		break;
+	case CS47L35:
+		if (IS_ENABLED(CONFIG_MFD_CS47L35)) {
+			regmap_16bit_config = &cs47l35_16bit_i2c_regmap;
+			regmap_32bit_config = &cs47l35_32bit_i2c_regmap;
+		}
+		break;
+	case CS47L85:
+	case WM1840:
+		if (IS_ENABLED(CONFIG_MFD_CS47L85)) {
+			regmap_16bit_config = &cs47l85_16bit_i2c_regmap;
+			regmap_32bit_config = &cs47l85_32bit_i2c_regmap;
+		}
+		break;
+	case CS47L90:
+	case CS47L91:
+		if (IS_ENABLED(CONFIG_MFD_CS47L90)) {
+			regmap_16bit_config = &cs47l90_16bit_i2c_regmap;
+			regmap_32bit_config = &cs47l90_32bit_i2c_regmap;
+		}
+		break;
+	case CS42L92:
+	case CS47L92:
+	case CS47L93:
+		if (IS_ENABLED(CONFIG_MFD_CS47L92)) {
+			regmap_16bit_config = &cs47l92_16bit_i2c_regmap;
+			regmap_32bit_config = &cs47l92_32bit_i2c_regmap;
+		}
+		break;
+	default:
+		dev_err(&i2c->dev,
+			"Unknown Madera I2C device type %ld\n", type);
+		return -EINVAL;
+	}
+
+	name = madera_name_from_type(type);
+
+	if (!regmap_16bit_config) {
+		/* it's polite to say which codec isn't built into the kernel */
+		dev_err(&i2c->dev,
+			"Kernel does not include support for %s\n", name);
+		return -EINVAL;
+	}
+
+	madera = devm_kzalloc(&i2c->dev, sizeof(*madera), GFP_KERNEL);
+	if (!madera)
+		return -ENOMEM;
+
+	madera->regmap = devm_regmap_init_i2c(i2c, regmap_16bit_config);
+	if (IS_ERR(madera->regmap)) {
+		ret = PTR_ERR(madera->regmap);
+		dev_err(&i2c->dev,
+			"Failed to allocate 16-bit register map: %d\n",	ret);
+		return ret;
+	}
+
+	madera->regmap_32bit = devm_regmap_init_i2c(i2c, regmap_32bit_config);
+	if (IS_ERR(madera->regmap_32bit)) {
+		ret = PTR_ERR(madera->regmap_32bit);
+		dev_err(&i2c->dev,
+			"Failed to allocate 32-bit register map: %d\n", ret);
+		return ret;
+	}
+
+	madera->type = type;
+	madera->type_name = name;
+	madera->dev = &i2c->dev;
+	madera->irq = i2c->irq;
+
+	return madera_dev_init(madera);
+}
+
+static void madera_i2c_remove(struct i2c_client *i2c)
+{
+	struct madera *madera = dev_get_drvdata(&i2c->dev);
+
+	madera_dev_exit(madera);
+}
+
+static const struct i2c_device_id madera_i2c_id[] = {
+	{ "cs47l15", CS47L15 },
+	{ "cs47l35", CS47L35 },
+	{ "cs47l85", CS47L85 },
+	{ "cs47l90", CS47L90 },
+	{ "cs47l91", CS47L91 },
+	{ "cs42l92", CS42L92 },
+	{ "cs47l92", CS47L92 },
+	{ "cs47l93", CS47L93 },
+	{ "wm1840", WM1840 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, madera_i2c_id);
+
+static struct i2c_driver madera_i2c_driver = {
+	.driver = {
+		.name	= "madera",
+		.pm	= &madera_pm_ops,
+		.of_match_table	= of_match_ptr(madera_of_match),
+	},
+	.probe		= madera_i2c_probe,
+	.remove		= madera_i2c_remove,
+	.id_table	= madera_i2c_id,
+};
+
+module_i2c_driver(madera_i2c_driver);
+
+MODULE_DESCRIPTION("Madera I2C bus interface");
+MODULE_AUTHOR("Richard Fitzgerald <rf@opensource.cirrus.com>");
+MODULE_LICENSE("GPL v2");