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 --- Documentation/admin-guide/media/vimc.dot | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) create mode 100644 Documentation/admin-guide/media/vimc.dot (limited to 'Documentation/admin-guide/media/vimc.dot') diff --git a/Documentation/admin-guide/media/vimc.dot b/Documentation/admin-guide/media/vimc.dot new file mode 100644 index 000000000..92a5bb631 --- /dev/null +++ b/Documentation/admin-guide/media/vimc.dot @@ -0,0 +1,26 @@ +# SPDX-License-Identifier: GPL-2.0 + +digraph board { + rankdir=TB + n00000001 [label="{{} | Sensor A\n/dev/v4l-subdev0 | { 0}}", shape=Mrecord, style=filled, fillcolor=green] + n00000001:port0 -> n00000005:port0 [style=bold] + n00000001:port0 -> n0000000b [style=bold] + n00000001 -> n00000002 + n00000002 [label="{{} | Lens A\n/dev/v4l-subdev5 | {}}", shape=Mrecord, style=filled, fillcolor=green] + n00000003 [label="{{} | Sensor B\n/dev/v4l-subdev1 | { 0}}", shape=Mrecord, style=filled, fillcolor=green] + n00000003:port0 -> n00000008:port0 [style=bold] + n00000003:port0 -> n0000000f [style=bold] + n00000003 -> n00000004 + n00000004 [label="{{} | Lens B\n/dev/v4l-subdev6 | {}}", shape=Mrecord, style=filled, fillcolor=green] + n00000005 [label="{{ 0} | Debayer A\n/dev/v4l-subdev2 | { 1}}", shape=Mrecord, style=filled, fillcolor=green] + n00000005:port1 -> n00000015:port0 + n00000008 [label="{{ 0} | Debayer B\n/dev/v4l-subdev3 | { 1}}", shape=Mrecord, style=filled, fillcolor=green] + n00000008:port1 -> n00000015:port0 [style=dashed] + n0000000b [label="Raw Capture 0\n/dev/video0", shape=box, style=filled, fillcolor=yellow] + n0000000f [label="Raw Capture 1\n/dev/video1", shape=box, style=filled, fillcolor=yellow] + n00000013 [label="{{} | RGB/YUV Input\n/dev/v4l-subdev4 | { 0}}", shape=Mrecord, style=filled, fillcolor=green] + n00000013:port0 -> n00000015:port0 [style=dashed] + n00000015 [label="{{ 0} | Scaler\n/dev/v4l-subdev5 | { 1}}", shape=Mrecord, style=filled, fillcolor=green] + n00000015:port1 -> n00000018 [style=bold] + n00000018 [label="RGB/YUV Capture\n/dev/video2", shape=box, style=filled, fillcolor=yellow] +} -- cgit v1.3.1