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, 180 insertions, 0 deletions

diff --git a/drivers/mfd/max77705.c b/drivers/mfd/max77705.c
new file mode 100644
index 000000000..e98c76d6b
--- /dev/null
+++ b/drivers/mfd/max77705.c
@@ -0,0 +1,180 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Maxim MAX77705 PMIC core driver
+ *
+ * Copyright (C) 2025 Dzmitry Sankouski <dsankouski@gmail.com>
+ **/
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/max77705-private.h>
+#include <linux/mfd/max77693-common.h>
+#include <linux/pm.h>
+#include <linux/power/max17042_battery.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/of.h>
+
+static struct mfd_cell max77705_devs[] = {
+	MFD_CELL_OF("max77705-rgb", NULL, NULL, 0, 0, "maxim,max77705-rgb"),
+	MFD_CELL_OF("max77705-charger", NULL, NULL, 0, 0, "maxim,max77705-charger"),
+	MFD_CELL_OF("max77705-haptic", NULL, NULL, 0, 0, "maxim,max77705-haptic"),
+};
+
+static const struct regmap_range max77705_readable_ranges[] = {
+	regmap_reg_range(MAX77705_PMIC_REG_PMICID1,		MAX77705_PMIC_REG_BSTOUT_MASK),
+	regmap_reg_range(MAX77705_PMIC_REG_INTSRC,		MAX77705_PMIC_REG_RESERVED_29),
+	regmap_reg_range(MAX77705_PMIC_REG_BOOSTCONTROL1,	MAX77705_PMIC_REG_BOOSTCONTROL1),
+	regmap_reg_range(MAX77705_PMIC_REG_MCONFIG,		MAX77705_PMIC_REG_MCONFIG2),
+	regmap_reg_range(MAX77705_PMIC_REG_FORCE_EN_MASK,	MAX77705_PMIC_REG_FORCE_EN_MASK),
+	regmap_reg_range(MAX77705_PMIC_REG_BOOSTCONTROL1,	MAX77705_PMIC_REG_BOOSTCONTROL1),
+	regmap_reg_range(MAX77705_PMIC_REG_BOOSTCONTROL2,	MAX77705_PMIC_REG_BOOSTCONTROL2),
+	regmap_reg_range(MAX77705_PMIC_REG_SW_RESET,		MAX77705_PMIC_REG_USBC_RESET),
+};
+
+static const struct regmap_range max77705_writable_ranges[] = {
+	regmap_reg_range(MAX77705_PMIC_REG_MAINCTRL1,		MAX77705_PMIC_REG_BSTOUT_MASK),
+	regmap_reg_range(MAX77705_PMIC_REG_INTSRC,		MAX77705_PMIC_REG_RESERVED_29),
+	regmap_reg_range(MAX77705_PMIC_REG_BOOSTCONTROL1,	MAX77705_PMIC_REG_BOOSTCONTROL1),
+	regmap_reg_range(MAX77705_PMIC_REG_MCONFIG,		MAX77705_PMIC_REG_MCONFIG2),
+	regmap_reg_range(MAX77705_PMIC_REG_FORCE_EN_MASK,	MAX77705_PMIC_REG_FORCE_EN_MASK),
+	regmap_reg_range(MAX77705_PMIC_REG_BOOSTCONTROL1,	MAX77705_PMIC_REG_BOOSTCONTROL1),
+	regmap_reg_range(MAX77705_PMIC_REG_BOOSTCONTROL2,	MAX77705_PMIC_REG_BOOSTCONTROL2),
+	regmap_reg_range(MAX77705_PMIC_REG_SW_RESET,		MAX77705_PMIC_REG_USBC_RESET),
+};
+
+static const struct regmap_access_table max77705_readable_table = {
+	.yes_ranges = max77705_readable_ranges,
+	.n_yes_ranges = ARRAY_SIZE(max77705_readable_ranges),
+};
+
+static const struct regmap_access_table max77705_writable_table = {
+	.yes_ranges = max77705_writable_ranges,
+	.n_yes_ranges = ARRAY_SIZE(max77705_writable_ranges),
+};
+
+static const struct regmap_config max77705_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.rd_table = &max77705_readable_table,
+	.wr_table = &max77705_writable_table,
+	.max_register = MAX77705_PMIC_REG_USBC_RESET,
+};
+
+static const struct regmap_irq max77705_irqs[] = {
+	{ .mask = MAX77705_SRC_IRQ_CHG, },
+	{ .mask = MAX77705_SRC_IRQ_TOP, },
+	{ .mask = MAX77705_SRC_IRQ_FG, },
+	{ .mask = MAX77705_SRC_IRQ_USBC, },
+};
+
+static const struct regmap_irq_chip max77705_irq_chip = {
+	.name		= "max77705",
+	.status_base	= MAX77705_PMIC_REG_INTSRC,
+	.ack_base	= MAX77705_PMIC_REG_INTSRC,
+	.mask_base	= MAX77705_PMIC_REG_INTSRC_MASK,
+	.num_regs	= 1,
+	.irqs		= max77705_irqs,
+	.num_irqs	= ARRAY_SIZE(max77705_irqs),
+};
+
+static int max77705_i2c_probe(struct i2c_client *i2c)
+{
+	struct device *dev = &i2c->dev;
+	struct max77693_dev *max77705;
+	struct regmap_irq_chip_data *irq_data;
+	struct irq_domain *domain;
+	enum max77705_hw_rev pmic_rev;
+	unsigned int pmic_rev_value;
+	int ret;
+
+	max77705 = devm_kzalloc(dev, sizeof(*max77705), GFP_KERNEL);
+	if (!max77705)
+		return -ENOMEM;
+
+	max77705->i2c = i2c;
+	max77705->type = TYPE_MAX77705;
+	i2c_set_clientdata(i2c, max77705);
+
+	max77705->regmap = devm_regmap_init_i2c(i2c, &max77705_regmap_config);
+	if (IS_ERR(max77705->regmap))
+		return PTR_ERR(max77705->regmap);
+
+	ret = regmap_read(max77705->regmap, MAX77705_PMIC_REG_PMICREV, &pmic_rev_value);
+	if (ret < 0)
+		return -ENODEV;
+
+	pmic_rev = pmic_rev_value & MAX77705_REVISION_MASK;
+	if (pmic_rev != MAX77705_PASS3)
+		return dev_err_probe(dev, -ENODEV, "Rev.0x%x is not tested\n", pmic_rev);
+
+	/* Active Discharge Enable */
+	regmap_update_bits(max77705->regmap, MAX77705_PMIC_REG_MAINCTRL1, 1, 1);
+
+	ret = devm_regmap_add_irq_chip(dev, max77705->regmap,
+					i2c->irq,
+					IRQF_ONESHOT, 0,
+					&max77705_irq_chip,
+					&irq_data);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to add IRQ chip\n");
+
+	domain = regmap_irq_get_domain(irq_data);
+
+	ret = devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE,
+				   max77705_devs, ARRAY_SIZE(max77705_devs),
+				   NULL, 0, domain);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to register child devices\n");
+
+	ret = devm_device_init_wakeup(dev);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to init wakeup\n");
+
+	return 0;
+}
+
+static int max77705_suspend(struct device *dev)
+{
+	struct i2c_client *i2c = to_i2c_client(dev);
+
+	disable_irq(i2c->irq);
+
+	if (device_may_wakeup(dev))
+		enable_irq_wake(i2c->irq);
+
+	return 0;
+}
+
+static int max77705_resume(struct device *dev)
+{
+	struct i2c_client *i2c = to_i2c_client(dev);
+
+	if (device_may_wakeup(dev))
+		disable_irq_wake(i2c->irq);
+
+	enable_irq(i2c->irq);
+
+	return 0;
+}
+static DEFINE_SIMPLE_DEV_PM_OPS(max77705_pm_ops, max77705_suspend, max77705_resume);
+
+static const struct of_device_id max77705_i2c_of_match[] = {
+	{ .compatible = "maxim,max77705" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, max77705_i2c_of_match);
+
+static struct i2c_driver max77705_i2c_driver = {
+	.driver = {
+		.name			= "max77705",
+		.of_match_table		= max77705_i2c_of_match,
+		.pm			= pm_sleep_ptr(&max77705_pm_ops),
+	},
+	.probe = max77705_i2c_probe
+};
+module_i2c_driver(max77705_i2c_driver);
+
+MODULE_DESCRIPTION("Maxim MAX77705 PMIC core driver");
+MODULE_AUTHOR("Dzmitry Sankouski <dsankouski@gmail.com>");
+MODULE_LICENSE("GPL");