netfs: zero the tail of a short DIO/unbuffered readgrafted

The buffered read collector zero-fills the tail of a short read that
stops below the inode's i_size (netfs_clear_unread()), so a read that
races an extending write still returns the expected number of bytes.
The non-buffered collector path does no such thing: it just records
how much was transferred.

Add the same zero-fill for the non-buffered case, gated on
NETFS_SREQ_CLEAR_TAIL: a subreq's source sets that flag when a short
result from it is known to be safe to treat as a hole, as opposed to
NETFS_SREQ_HIT_EOF, which means the read genuinely ran off the end of
the file and should be reported short as-is. Only CLEAR_TAIL should
zero-fill here; a real EOF must stay a real short read.

No source currently sets CLEAR_TAIL on an unbuffered/DIO subrequest,
so this is inert on its own -- a following change teaches cifs to set
it in the one case that needs it.

Fixes: e2d46f2ec332 ("netfs: Change the read result collector to only use one work item")
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org

1 files changed, 267 insertions, 0 deletions

diff --git a/drivers/mfd/sec-i2c.c b/drivers/mfd/sec-i2c.c
new file mode 100644
index 000000000..4eec8f7ce
--- /dev/null
+++ b/drivers/mfd/sec-i2c.c
@@ -0,0 +1,267 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2012 Samsung Electronics Co., Ltd
+ *                http://www.samsung.com
+ * Copyright 2025 Linaro Ltd.
+ *
+ * Samsung SxM I2C driver
+ */
+
+#include <linux/dev_printk.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/mfd/samsung/core.h>
+#include <linux/mfd/samsung/s2mpa01.h>
+#include <linux/mfd/samsung/s2mps11.h>
+#include <linux/mfd/samsung/s2mps13.h>
+#include <linux/mfd/samsung/s2mps14.h>
+#include <linux/mfd/samsung/s2mps15.h>
+#include <linux/mfd/samsung/s2mpu02.h>
+#include <linux/mfd/samsung/s2mu005.h>
+#include <linux/mfd/samsung/s5m8767.h>
+#include <linux/module.h>
+#include <linux/pm.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+#include "sec-core.h"
+
+struct sec_pmic_i2c_platform_data {
+	const struct regmap_config *regmap_cfg;
+	int device_type;
+};
+
+static bool s2mpa01_volatile(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case S2MPA01_REG_INT1M:
+	case S2MPA01_REG_INT2M:
+	case S2MPA01_REG_INT3M:
+		return false;
+	default:
+		return true;
+	}
+}
+
+static bool s2mps11_volatile(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case S2MPS11_REG_INT1M:
+	case S2MPS11_REG_INT2M:
+	case S2MPS11_REG_INT3M:
+		return false;
+	default:
+		return true;
+	}
+}
+
+static bool s2mpu02_volatile(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case S2MPU02_REG_INT1M:
+	case S2MPU02_REG_INT2M:
+	case S2MPU02_REG_INT3M:
+		return false;
+	default:
+		return true;
+	}
+}
+
+static bool s2mu005_volatile(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case S2MU005_REG_CHGR_INT1M:
+	case S2MU005_REG_FLED_INT1M:
+	case S2MU005_REG_MUIC_INT1M:
+	case S2MU005_REG_MUIC_INT2M:
+		return false;
+	default:
+		return true;
+	}
+}
+
+static const struct regmap_config s2dos05_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+};
+
+static const struct regmap_config s2mpa01_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+
+	.max_register = S2MPA01_REG_LDO_OVCB4,
+	.volatile_reg = s2mpa01_volatile,
+	.cache_type = REGCACHE_FLAT,
+};
+
+static const struct regmap_config s2mps11_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+
+	.max_register = S2MPS11_REG_L38CTRL,
+	.volatile_reg = s2mps11_volatile,
+	.cache_type = REGCACHE_FLAT,
+};
+
+static const struct regmap_config s2mps13_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+
+	.max_register = S2MPS13_REG_LDODSCH5,
+	.volatile_reg = s2mps11_volatile,
+	.cache_type = REGCACHE_FLAT,
+};
+
+static const struct regmap_config s2mps14_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+
+	.max_register = S2MPS14_REG_LDODSCH3,
+	.volatile_reg = s2mps11_volatile,
+	.cache_type = REGCACHE_FLAT,
+};
+
+static const struct regmap_config s2mps15_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+
+	.max_register = S2MPS15_REG_LDODSCH4,
+	.volatile_reg = s2mps11_volatile,
+	.cache_type = REGCACHE_FLAT,
+};
+
+static const struct regmap_config s2mpu02_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+
+	.max_register = S2MPU02_REG_DVSDATA,
+	.volatile_reg = s2mpu02_volatile,
+	.cache_type = REGCACHE_FLAT,
+};
+
+static const struct regmap_config s2mpu05_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+};
+
+static const struct regmap_config s2mu005_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+
+	.max_register = S2MU005_REG_MUIC_LDOADC_H,
+	.volatile_reg = s2mu005_volatile,
+	.cache_type = REGCACHE_FLAT_S,
+};
+
+static const struct regmap_config s5m8767_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+
+	.max_register = S5M8767_REG_LDO28CTRL,
+	.volatile_reg = s2mps11_volatile,
+	.cache_type = REGCACHE_FLAT,
+};
+
+static int sec_pmic_i2c_probe(struct i2c_client *client)
+{
+	const struct sec_pmic_i2c_platform_data *pdata;
+	struct regmap *regmap_pmic;
+
+	pdata = device_get_match_data(&client->dev);
+	if (!pdata)
+		return dev_err_probe(&client->dev, -ENODEV,
+				     "Unsupported device type\n");
+
+	regmap_pmic = devm_regmap_init_i2c(client, pdata->regmap_cfg);
+	if (IS_ERR(regmap_pmic))
+		return dev_err_probe(&client->dev, PTR_ERR(regmap_pmic),
+				     "regmap init failed\n");
+
+	return sec_pmic_probe(&client->dev, pdata->device_type, client->irq,
+			      regmap_pmic, client);
+}
+
+static void sec_pmic_i2c_shutdown(struct i2c_client *i2c)
+{
+	sec_pmic_shutdown(&i2c->dev);
+}
+
+static const struct sec_pmic_i2c_platform_data s2dos05_data = {
+	.regmap_cfg = &s2dos05_regmap_config,
+	.device_type = S2DOS05
+};
+
+static const struct sec_pmic_i2c_platform_data s2mpa01_data = {
+	.regmap_cfg = &s2mpa01_regmap_config,
+	.device_type = S2MPA01,
+};
+
+static const struct sec_pmic_i2c_platform_data s2mps11_data = {
+	.regmap_cfg = &s2mps11_regmap_config,
+	.device_type = S2MPS11X,
+};
+
+static const struct sec_pmic_i2c_platform_data s2mps13_data = {
+	.regmap_cfg = &s2mps13_regmap_config,
+	.device_type = S2MPS13X,
+};
+
+static const struct sec_pmic_i2c_platform_data s2mps14_data = {
+	.regmap_cfg = &s2mps14_regmap_config,
+	.device_type = S2MPS14X,
+};
+
+static const struct sec_pmic_i2c_platform_data s2mps15_data = {
+	.regmap_cfg = &s2mps15_regmap_config,
+	.device_type = S2MPS15X,
+};
+
+static const struct sec_pmic_i2c_platform_data s2mpu02_data = {
+	.regmap_cfg = &s2mpu02_regmap_config,
+	.device_type = S2MPU02,
+};
+
+static const struct sec_pmic_i2c_platform_data s2mpu05_data = {
+	.regmap_cfg = &s2mpu05_regmap_config,
+	.device_type = S2MPU05,
+};
+
+static const struct sec_pmic_i2c_platform_data s2mu005_data = {
+	.regmap_cfg = &s2mu005_regmap_config,
+	.device_type = S2MU005,
+};
+
+static const struct sec_pmic_i2c_platform_data s5m8767_data = {
+	.regmap_cfg = &s5m8767_regmap_config,
+	.device_type = S5M8767X,
+};
+
+static const struct of_device_id sec_pmic_i2c_of_match[] = {
+	{ .compatible = "samsung,s2dos05", .data = &s2dos05_data, },
+	{ .compatible = "samsung,s2mpa01-pmic", .data = &s2mpa01_data, },
+	{ .compatible = "samsung,s2mps11-pmic", .data = &s2mps11_data, },
+	{ .compatible = "samsung,s2mps13-pmic", .data = &s2mps13_data, },
+	{ .compatible = "samsung,s2mps14-pmic", .data = &s2mps14_data, },
+	{ .compatible = "samsung,s2mps15-pmic", .data = &s2mps15_data, },
+	{ .compatible = "samsung,s2mpu02-pmic", .data = &s2mpu02_data, },
+	{ .compatible = "samsung,s2mpu05-pmic", .data = &s2mpu05_data, },
+	{ .compatible = "samsung,s2mu005-pmic", .data = &s2mu005_data, },
+	{ .compatible = "samsung,s5m8767-pmic", .data = &s5m8767_data, },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, sec_pmic_i2c_of_match);
+
+static struct i2c_driver sec_pmic_i2c_driver = {
+	.driver = {
+		.name = "sec-pmic-i2c",
+		.pm = pm_sleep_ptr(&sec_pmic_pm_ops),
+		.of_match_table = sec_pmic_i2c_of_match,
+	},
+	.probe = sec_pmic_i2c_probe,
+	.shutdown = sec_pmic_i2c_shutdown,
+};
+module_i2c_driver(sec_pmic_i2c_driver);
+
+MODULE_AUTHOR("Sangbeom Kim <sbkim73@samsung.com>");
+MODULE_AUTHOR("André Draszik <andre.draszik@linaro.org>");
+MODULE_DESCRIPTION("I2C driver for the Samsung S5M");
+MODULE_LICENSE("GPL");