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/input/touchscreen/touchit213.c | 214 +++++++++++++++++++++++++++++++++ 1 file changed, 214 insertions(+) create mode 100644 drivers/input/touchscreen/touchit213.c (limited to 'drivers/input/touchscreen/touchit213.c') diff --git a/drivers/input/touchscreen/touchit213.c b/drivers/input/touchscreen/touchit213.c new file mode 100644 index 000000000..6d4a1acf5 --- /dev/null +++ b/drivers/input/touchscreen/touchit213.c @@ -0,0 +1,214 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Sahara TouchIT-213 serial touchscreen driver + * + * Copyright (c) 2007-2008 Claudio Nieder + * + * Based on Touchright driver (drivers/input/touchscreen/touchright.c) + * Copyright (c) 2006 Rick Koch + * Copyright (c) 2004 Vojtech Pavlik + * and Dan Streetman + */ + + +#include +#include +#include +#include +#include +#include + +#define DRIVER_DESC "Sahara TouchIT-213 serial touchscreen driver" + +MODULE_AUTHOR("Claudio Nieder "); +MODULE_DESCRIPTION(DRIVER_DESC); +MODULE_LICENSE("GPL"); + +/* + * Definitions & global arrays. + */ + +/* + * Data is received through COM1 at 9600bit/s,8bit,no parity in packets + * of 5 byte each. + * + * +--------+ +--------+ +--------+ +--------+ +--------+ + * |1000000p| |0xxxxxxx| |0xxxxxxx| |0yyyyyyy| |0yyyyyyy| + * +--------+ +--------+ +--------+ +--------+ +--------+ + * MSB LSB MSB LSB + * + * The value of p is 1 as long as the screen is touched and 0 when + * reporting the location where touching stopped, e.g. where the pen was + * lifted from the screen. + * + * When holding the screen in landscape mode as the BIOS text output is + * presented, x is the horizontal axis with values growing from left to + * right and y is the vertical axis with values growing from top to + * bottom. + * + * When holding the screen in portrait mode with the Sahara logo in its + * correct position, x ist the vertical axis with values growing from + * top to bottom and y is the horizontal axis with values growing from + * right to left. + */ + +#define T213_FORMAT_TOUCH_BIT 0x01 +#define T213_FORMAT_STATUS_BYTE 0x80 +#define T213_FORMAT_STATUS_MASK ~T213_FORMAT_TOUCH_BIT + +/* + * On my Sahara Touch-IT 213 I have observed x values from 0 to 0x7f0 + * and y values from 0x1d to 0x7e9, so the actual measurement is + * probably done with an 11 bit precision. + */ +#define T213_MIN_XC 0 +#define T213_MAX_XC 0x07ff +#define T213_MIN_YC 0 +#define T213_MAX_YC 0x07ff + +/* + * Per-touchscreen data. + */ + +struct touchit213 { + struct input_dev *dev; + struct serio *serio; + int idx; + unsigned char csum; + unsigned char data[5]; + char phys[32]; +}; + +static irqreturn_t touchit213_interrupt(struct serio *serio, + unsigned char data, unsigned int flags) +{ + struct touchit213 *touchit213 = serio_get_drvdata(serio); + struct input_dev *dev = touchit213->dev; + + touchit213->data[touchit213->idx] = data; + + switch (touchit213->idx++) { + case 0: + if ((touchit213->data[0] & T213_FORMAT_STATUS_MASK) != + T213_FORMAT_STATUS_BYTE) { + pr_debug("unsynchronized data: 0x%02x\n", data); + touchit213->idx = 0; + } + break; + + case 4: + touchit213->idx = 0; + input_report_abs(dev, ABS_X, + (touchit213->data[1] << 7) | touchit213->data[2]); + input_report_abs(dev, ABS_Y, + (touchit213->data[3] << 7) | touchit213->data[4]); + input_report_key(dev, BTN_TOUCH, + touchit213->data[0] & T213_FORMAT_TOUCH_BIT); + input_sync(dev); + break; + } + + return IRQ_HANDLED; +} + +/* + * touchit213_disconnect() is the opposite of touchit213_connect() + */ + +static void touchit213_disconnect(struct serio *serio) +{ + struct touchit213 *touchit213 = serio_get_drvdata(serio); + + input_get_device(touchit213->dev); + input_unregister_device(touchit213->dev); + serio_close(serio); + serio_set_drvdata(serio, NULL); + input_put_device(touchit213->dev); + kfree(touchit213); +} + +/* + * touchit213_connect() is the routine that is called when someone adds a + * new serio device that supports the Touchright protocol and registers it as + * an input device. + */ + +static int touchit213_connect(struct serio *serio, struct serio_driver *drv) +{ + struct touchit213 *touchit213; + struct input_dev *input_dev; + int err; + + touchit213 = kzalloc_obj(*touchit213); + input_dev = input_allocate_device(); + if (!touchit213 || !input_dev) { + err = -ENOMEM; + goto fail1; + } + + touchit213->serio = serio; + touchit213->dev = input_dev; + scnprintf(touchit213->phys, sizeof(touchit213->phys), + "%s/input0", serio->phys); + + input_dev->name = "Sahara Touch-iT213 Serial TouchScreen"; + input_dev->phys = touchit213->phys; + input_dev->id.bustype = BUS_RS232; + input_dev->id.vendor = SERIO_TOUCHIT213; + input_dev->id.product = 0; + input_dev->id.version = 0x0100; + input_dev->dev.parent = &serio->dev; + input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS); + input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH); + input_set_abs_params(touchit213->dev, ABS_X, + T213_MIN_XC, T213_MAX_XC, 0, 0); + input_set_abs_params(touchit213->dev, ABS_Y, + T213_MIN_YC, T213_MAX_YC, 0, 0); + + serio_set_drvdata(serio, touchit213); + + err = serio_open(serio, drv); + if (err) + goto fail2; + + err = input_register_device(touchit213->dev); + if (err) + goto fail3; + + return 0; + + fail3: serio_close(serio); + fail2: serio_set_drvdata(serio, NULL); + fail1: input_free_device(input_dev); + kfree(touchit213); + return err; +} + +/* + * The serio driver structure. + */ + +static const struct serio_device_id touchit213_serio_ids[] = { + { + .type = SERIO_RS232, + .proto = SERIO_TOUCHIT213, + .id = SERIO_ANY, + .extra = SERIO_ANY, + }, + { 0 } +}; + +MODULE_DEVICE_TABLE(serio, touchit213_serio_ids); + +static struct serio_driver touchit213_drv = { + .driver = { + .name = "touchit213", + }, + .description = DRIVER_DESC, + .id_table = touchit213_serio_ids, + .interrupt = touchit213_interrupt, + .connect = touchit213_connect, + .disconnect = touchit213_disconnect, +}; + +module_serio_driver(touchit213_drv); -- cgit v1.3.1