From dd05add7b2b6004c5fa3a1f276f56d8668f86b65 Mon Sep 17 00:00:00 2001 From: Paulo Alcantara Date: Sat, 26 Sep 2026 19:20:30 -0300 Subject: netfs: zero the tail of a short DIO/unbuffered read 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 Reviewed-by: Namjae Jeon Signed-off-by: Paulo Alcantara Cc: Christian Brauner Cc: Matthew Wilcox Cc: Ronnie Sahlberg Cc: Shyam Prasad N Cc: Tom Talpey Cc: Bharath SM Cc: stable@vger.kernel.org --- drivers/reset/reset-gpio.c | 99 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 99 insertions(+) create mode 100644 drivers/reset/reset-gpio.c (limited to 'drivers/reset/reset-gpio.c') diff --git a/drivers/reset/reset-gpio.c b/drivers/reset/reset-gpio.c new file mode 100644 index 000000000..bf95296a5 --- /dev/null +++ b/drivers/reset/reset-gpio.c @@ -0,0 +1,99 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include +#include +#include + +struct reset_gpio_priv { + struct reset_controller_dev rc; + struct gpio_desc *reset; +}; + +static inline struct reset_gpio_priv +*rc_to_reset_gpio(struct reset_controller_dev *rc) +{ + return container_of(rc, struct reset_gpio_priv, rc); +} + +static int reset_gpio_assert(struct reset_controller_dev *rc, unsigned long id) +{ + struct reset_gpio_priv *priv = rc_to_reset_gpio(rc); + + return gpiod_set_value_cansleep(priv->reset, 1); +} + +static int reset_gpio_deassert(struct reset_controller_dev *rc, + unsigned long id) +{ + struct reset_gpio_priv *priv = rc_to_reset_gpio(rc); + + return gpiod_set_value_cansleep(priv->reset, 0); +} + +static int reset_gpio_status(struct reset_controller_dev *rc, unsigned long id) +{ + struct reset_gpio_priv *priv = rc_to_reset_gpio(rc); + + return gpiod_get_value_cansleep(priv->reset); +} + +static const struct reset_control_ops reset_gpio_ops = { + .assert = reset_gpio_assert, + .deassert = reset_gpio_deassert, + .status = reset_gpio_status, +}; + +static int reset_gpio_fwnode_xlate(struct reset_controller_dev *rcdev, + const struct fwnode_reference_args *reset_spec) +{ + return reset_spec->args[0]; +} + +static int reset_gpio_probe(struct auxiliary_device *adev, + const struct auxiliary_device_id *id) +{ + struct device *dev = &adev->dev; + struct reset_gpio_priv *priv; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH); + if (IS_ERR(priv->reset)) + return dev_err_probe(dev, PTR_ERR(priv->reset), + "Could not get reset gpios\n"); + + priv->rc.ops = &reset_gpio_ops; + priv->rc.owner = THIS_MODULE; + priv->rc.dev = dev; + + /* Cells to match GPIO specifier, but it's not really used */ + priv->rc.fwnode_reset_n_cells = 2; + priv->rc.fwnode_xlate = reset_gpio_fwnode_xlate; + priv->rc.nr_resets = 1; + + return devm_reset_controller_register(dev, &priv->rc); +} + +static const struct auxiliary_device_id reset_gpio_ids[] = { + { .name = "reset.gpio" }, + {} +}; +MODULE_DEVICE_TABLE(auxiliary, reset_gpio_ids); + +static struct auxiliary_driver reset_gpio_driver = { + .probe = reset_gpio_probe, + .id_table = reset_gpio_ids, + .driver = { + .name = "reset-gpio", + .suppress_bind_attrs = true, + }, +}; +module_auxiliary_driver(reset_gpio_driver); + +MODULE_AUTHOR("Krzysztof Kozlowski "); +MODULE_DESCRIPTION("Generic GPIO reset driver"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1