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/rtc/rtc-generic.c | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 drivers/rtc/rtc-generic.c (limited to 'drivers/rtc/rtc-generic.c') diff --git a/drivers/rtc/rtc-generic.c b/drivers/rtc/rtc-generic.c new file mode 100644 index 000000000..89ae78e93 --- /dev/null +++ b/drivers/rtc/rtc-generic.c @@ -0,0 +1,39 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* rtc-generic: RTC driver using the generic RTC abstraction + * + * Copyright (C) 2008 Kyle McMartin + */ + +#include +#include +#include +#include +#include + +static int __init generic_rtc_probe(struct platform_device *dev) +{ + struct rtc_device *rtc; + const struct rtc_class_ops *ops = dev_get_platdata(&dev->dev); + + rtc = devm_rtc_device_register(&dev->dev, "rtc-generic", + ops, THIS_MODULE); + if (IS_ERR(rtc)) + return PTR_ERR(rtc); + + platform_set_drvdata(dev, rtc); + + return 0; +} + +static struct platform_driver generic_rtc_driver = { + .driver = { + .name = "rtc-generic", + }, +}; + +module_platform_driver_probe(generic_rtc_driver, generic_rtc_probe); + +MODULE_AUTHOR("Kyle McMartin "); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Generic RTC driver"); +MODULE_ALIAS("platform:rtc-generic"); -- cgit v1.3.1