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/hid/hid-emsff.c | 115 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 115 insertions(+) create mode 100644 drivers/hid/hid-emsff.c (limited to 'drivers/hid/hid-emsff.c') diff --git a/drivers/hid/hid-emsff.c b/drivers/hid/hid-emsff.c new file mode 100644 index 000000000..d8e559e05 --- /dev/null +++ b/drivers/hid/hid-emsff.c @@ -0,0 +1,115 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Force feedback support for EMS Trio Linker Plus II + * + * Copyright (c) 2010 Ignaz Forster + */ + +/* + */ + + +#include +#include +#include + +#include "hid-ids.h" + +struct emsff_device { + struct hid_report *report; +}; + +static int emsff_play(struct input_dev *dev, void *data, + struct ff_effect *effect) +{ + struct hid_device *hid = input_get_drvdata(dev); + struct emsff_device *emsff = data; + int weak, strong; + + weak = effect->u.rumble.weak_magnitude; + strong = effect->u.rumble.strong_magnitude; + + dbg_hid("called with 0x%04x 0x%04x\n", strong, weak); + + weak = weak * 0xff / 0xffff; + strong = strong * 0xff / 0xffff; + + emsff->report->field[0]->value[1] = weak; + emsff->report->field[0]->value[2] = strong; + + dbg_hid("running with 0x%02x 0x%02x\n", strong, weak); + hid_hw_request(hid, emsff->report, HID_REQ_SET_REPORT); + + return 0; +} + +static int ems_input_configured(struct hid_device *hid, struct hid_input *hidinput) +{ + struct emsff_device *emsff; + struct hid_report *report; + struct list_head *report_list = + &hid->report_enum[HID_OUTPUT_REPORT].report_list; + struct input_dev *dev = hidinput->input; + int error; + + if (!list_is_first(&hidinput->list, &hid->inputs)) + return 0; + + report = list_first_entry_or_null(report_list, struct hid_report, list); + if (!report) { + hid_err(hid, "no output reports found\n"); + return -ENODEV; + } + if (report->maxfield < 1) { + hid_err(hid, "no fields in the report\n"); + return -ENODEV; + } + + if (report->field[0]->report_count < 7) { + hid_err(hid, "not enough values in the field\n"); + return -ENODEV; + } + + emsff = kzalloc_obj(struct emsff_device); + if (!emsff) + return -ENOMEM; + + emsff->report = report; + set_bit(FF_RUMBLE, dev->ffbit); + + error = input_ff_create_memless(dev, emsff, emsff_play); + if (error) { + kfree(emsff); + return error; + } + + emsff->report->field[0]->value[0] = 0x01; + emsff->report->field[0]->value[1] = 0x00; + emsff->report->field[0]->value[2] = 0x00; + emsff->report->field[0]->value[3] = 0x00; + emsff->report->field[0]->value[4] = 0x00; + emsff->report->field[0]->value[5] = 0x00; + emsff->report->field[0]->value[6] = 0x00; + hid_hw_request(hid, emsff->report, HID_REQ_SET_REPORT); + + hid_info(hid, "force feedback for EMS based devices by Ignaz Forster \n"); + + return 0; +} + +static const struct hid_device_id ems_devices[] = { + { HID_USB_DEVICE(USB_VENDOR_ID_EMS, USB_DEVICE_ID_EMS_TRIO_LINKER_PLUS_II) }, + { } +}; +MODULE_DEVICE_TABLE(hid, ems_devices); + +static struct hid_driver ems_driver = { + .name = "hkems", + .id_table = ems_devices, + .input_configured = ems_input_configured, +}; +module_hid_driver(ems_driver); + +MODULE_DESCRIPTION("Force feedback support for EMS Trio Linker Plus II"); +MODULE_LICENSE("GPL"); + -- cgit v1.3.1