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/input-compat.c | 165 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 165 insertions(+) create mode 100644 drivers/input/input-compat.c (limited to 'drivers/input/input-compat.c') diff --git a/drivers/input/input-compat.c b/drivers/input/input-compat.c new file mode 100644 index 000000000..8860a0730 --- /dev/null +++ b/drivers/input/input-compat.c @@ -0,0 +1,165 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * 32bit compatibility wrappers for the input subsystem. + * + * Very heavily based on evdev.c - Copyright (c) 1999-2002 Vojtech Pavlik + */ + +#include +#include +#include +#include "input-compat.h" + +#ifdef CONFIG_COMPAT + +int input_event_from_user(const char __user *buffer, + struct input_event *event) +{ + if (in_compat_syscall() && !COMPAT_USE_64BIT_TIME) { + struct input_event_compat compat_event; + + if (copy_from_user(&compat_event, buffer, + sizeof(struct input_event_compat))) + return -EFAULT; + + event->input_event_sec = compat_event.sec; + event->input_event_usec = compat_event.usec; + event->type = compat_event.type; + event->code = compat_event.code; + event->value = compat_event.value; + + } else { + if (copy_from_user(event, buffer, sizeof(struct input_event))) + return -EFAULT; + } + + return 0; +} + +int input_event_to_user(char __user *buffer, + const struct input_event *event) +{ + if (in_compat_syscall() && !COMPAT_USE_64BIT_TIME) { + struct input_event_compat compat_event; + + compat_event.sec = event->input_event_sec; + compat_event.usec = event->input_event_usec; + compat_event.type = event->type; + compat_event.code = event->code; + compat_event.value = event->value; + + if (copy_to_user(buffer, &compat_event, + sizeof(struct input_event_compat))) + return -EFAULT; + + } else { + if (copy_to_user(buffer, event, sizeof(struct input_event))) + return -EFAULT; + } + + return 0; +} + +int input_ff_effect_from_user(const char __user *buffer, size_t size, + struct ff_effect *effect) +{ + if (in_compat_syscall()) { + struct ff_effect_compat *compat_effect; + + if (size != sizeof(struct ff_effect_compat)) + return -EINVAL; + + /* + * It so happens that the pointer which needs to be changed + * is the last field in the structure, so we can retrieve the + * whole thing and replace just the pointer. + */ + compat_effect = (struct ff_effect_compat *)effect; + + memset(effect, 0, sizeof(*effect)); + + if (copy_from_user(compat_effect, buffer, + sizeof(struct ff_effect_compat))) + return -EFAULT; + + if (compat_effect->type == FF_PERIODIC && + compat_effect->u.periodic.waveform == FF_CUSTOM) + effect->u.periodic.custom_data = + compat_ptr(compat_effect->u.periodic.custom_data); + } else { + if (size != sizeof(struct ff_effect)) + return -EINVAL; + + if (copy_from_user(effect, buffer, sizeof(struct ff_effect))) + return -EFAULT; + } + + return 0; +} + +int input_bits_to_string(char *buf, int buf_size, unsigned long bits, + bool skip_empty) +{ + int len = 0; + + if (in_compat_syscall()) { + u32 dword = bits >> 32; + if (dword || !skip_empty) + len += snprintf(buf, buf_size, "%x ", dword); + + dword = bits & 0xffffffffUL; + if (dword || !skip_empty || len) + len += snprintf(buf + len, max(buf_size - len, 0), + "%x", dword); + } else { + if (bits || !skip_empty) + len += snprintf(buf, buf_size, "%lx", bits); + } + + return len; +} + +#else + +int input_event_from_user(const char __user *buffer, + struct input_event *event) +{ + if (copy_from_user(event, buffer, sizeof(struct input_event))) + return -EFAULT; + + return 0; +} + +int input_event_to_user(char __user *buffer, + const struct input_event *event) +{ + if (copy_to_user(buffer, event, sizeof(struct input_event))) + return -EFAULT; + + return 0; +} + +int input_ff_effect_from_user(const char __user *buffer, size_t size, + struct ff_effect *effect) +{ + if (size != sizeof(struct ff_effect)) + return -EINVAL; + + if (copy_from_user(effect, buffer, sizeof(struct ff_effect))) + return -EFAULT; + + return 0; +} + +int input_bits_to_string(char *buf, int buf_size, unsigned long bits, + bool skip_empty) +{ + return bits || !skip_empty ? + snprintf(buf, buf_size, "%lx", bits) : 0; +} + +#endif /* CONFIG_COMPAT */ + +EXPORT_SYMBOL_GPL(input_event_from_user); +EXPORT_SYMBOL_GPL(input_event_to_user); +EXPORT_SYMBOL_GPL(input_ff_effect_from_user); -- cgit v1.3.1