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/char/nwbutton.h | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 drivers/char/nwbutton.h (limited to 'drivers/char/nwbutton.h') diff --git a/drivers/char/nwbutton.h b/drivers/char/nwbutton.h new file mode 100644 index 000000000..f2b9fdc1f --- /dev/null +++ b/drivers/char/nwbutton.h @@ -0,0 +1,40 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __NWBUTTON_H +#define __NWBUTTON_H + +/* + * NetWinder Button Driver- + * Copyright (C) Alex Holden 1998, 1999. + */ + +#ifdef __NWBUTTON_C /* Actually compiling the driver itself */ + +/* Various defines: */ + +#define NUM_PRESSES_REBOOT 2 /* How many presses to activate shutdown */ +#define BUTTON_DELAY 30 /* How many jiffies for sequence to end */ +#define VERSION "0.3" /* Driver version number */ + +/* Structure definitions: */ + +struct button_callback { + void (*callback) (void); + int count; +}; + +/* Function prototypes: */ + +static void button_sequence_finished(struct timer_list *unused); +static irqreturn_t button_handler (int irq, void *dev_id); +int button_init (void); +int button_add_callback (void (*callback) (void), int count); +int button_del_callback (void (*callback) (void)); +static void button_consume_callbacks (int bpcount); + +#else /* Not compiling the driver itself */ + +extern int button_add_callback (void (*callback) (void), int count); +extern int button_del_callback (void (*callback) (void)); + +#endif /* __NWBUTTON_C */ +#endif /* __NWBUTTON_H */ -- cgit v1.3.1