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/driver-api/basics.rst | 151 ++++++++++++++++++++++++++++++++++++ 1 file changed, 151 insertions(+) create mode 100644 Documentation/driver-api/basics.rst (limited to 'Documentation/driver-api/basics.rst') diff --git a/Documentation/driver-api/basics.rst b/Documentation/driver-api/basics.rst new file mode 100644 index 000000000..3b182cfdf --- /dev/null +++ b/Documentation/driver-api/basics.rst @@ -0,0 +1,151 @@ +Driver Basics +============= + +Driver Entry and Exit points +---------------------------- + +.. kernel-doc:: include/linux/module.h + :internal: + +Driver device table +------------------- + +.. kernel-doc:: include/linux/mod_devicetable.h + :internal: + :no-identifiers: pci_device_id + + +Delaying and scheduling routines +-------------------------------- + +.. kernel-doc:: include/linux/sched.h + :internal: + +.. kernel-doc:: kernel/sched/core.c + :export: + +.. kernel-doc:: kernel/sched/cpupri.c + :internal: + +.. kernel-doc:: kernel/sched/fair.c + :internal: + +.. kernel-doc:: include/linux/completion.h + :internal: + +Time and timer routines +----------------------- + +.. kernel-doc:: include/linux/jiffies.h + :internal: + +.. kernel-doc:: kernel/time/time.c + :export: + +.. kernel-doc:: kernel/time/timer.c + :export: + +High-resolution timers +---------------------- + +.. kernel-doc:: include/linux/ktime.h + :internal: + +.. kernel-doc:: include/linux/hrtimer.h + :internal: + +.. kernel-doc:: kernel/time/hrtimer.c + :export: + +Wait queues and Wake events +--------------------------- + +.. kernel-doc:: include/linux/wait.h + :internal: + +.. kernel-doc:: kernel/sched/wait.c + :export: + +Internal Functions +------------------ + +.. kernel-doc:: kernel/exit.c + :internal: + +.. kernel-doc:: kernel/signal.c + :internal: + +.. kernel-doc:: include/linux/kthread.h + :internal: + +.. kernel-doc:: kernel/kthread.c + :export: + +Reference counting +------------------ + +.. kernel-doc:: include/linux/refcount.h + :internal: + +.. kernel-doc:: lib/refcount.c + :export: + +.. kernel-doc:: include/linux/percpu-refcount.h +.. kernel-doc:: lib/percpu-refcount.c + +Atomics +------- + +.. kernel-doc:: include/linux/atomic/atomic-instrumented.h + :internal: + +.. kernel-doc:: include/linux/atomic/atomic-arch-fallback.h + :internal: + +.. kernel-doc:: include/linux/atomic/atomic-long.h + :internal: + +Kernel objects manipulation +--------------------------- + +.. kernel-doc:: lib/kobject.c + :export: + +.. kernel-doc:: lib/kobject_uevent.c + :export: + +Kernel utility functions +------------------------ + +.. kernel-doc:: include/linux/array_size.h + :internal: + +.. kernel-doc:: include/linux/container_of.h + :internal: + +.. kernel-doc:: include/linux/kstrtox.h + :internal: + :no-identifiers: kstrtol kstrtoul + +.. kernel-doc:: include/linux/stddef.h + :internal: + +.. kernel-doc:: include/linux/util_macros.h + :internal: + +.. kernel-doc:: include/linux/wordpart.h + :internal: + +.. kernel-doc:: kernel/printk/printk.c + :export: + :no-identifiers: printk + +.. kernel-doc:: kernel/panic.c + :export: + +Device Resource Management +-------------------------- + +.. kernel-doc:: drivers/base/devres.c + :export: + -- cgit v1.3.1