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/pps/Kconfig | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100644 drivers/pps/Kconfig (limited to 'drivers/pps/Kconfig') diff --git a/drivers/pps/Kconfig b/drivers/pps/Kconfig new file mode 100644 index 000000000..e1651d51c --- /dev/null +++ b/drivers/pps/Kconfig @@ -0,0 +1,45 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# PPS support configuration +# + +menuconfig PPS + tristate "PPS support" + help + PPS (Pulse Per Second) is a special pulse provided by some GPS + antennae. Userland can use it to get a high-precision time + reference. + + Some antennae's PPS signals are connected with the CD (Carrier + Detect) pin of the serial line they use to communicate with the + host. In this case use the SERIAL_LINE client support. + + Some antennae's PPS signals are connected with some special host + inputs so you have to enable the corresponding client support. + + To compile this driver as a module, choose M here: the module + will be called pps_core.ko. + +if PPS + +config PPS_DEBUG + bool "PPS debugging messages" + help + Say Y here if you want the PPS support to produce a bunch of debug + messages to the system log. Select this if you are having a + problem with PPS support and want to see more of what is going on. + +config NTP_PPS + bool "PPS kernel consumer support" + depends on !NO_HZ_COMMON + help + This option adds support for direct in-kernel time + synchronization using an external PPS signal. + + It doesn't work on tickless systems at the moment. + +source "drivers/pps/clients/Kconfig" + +source "drivers/pps/generators/Kconfig" + +endif # PPS -- cgit v1.3.1