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/comedi/comedi_internal.h | 86 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 86 insertions(+) create mode 100644 drivers/comedi/comedi_internal.h (limited to 'drivers/comedi/comedi_internal.h') diff --git a/drivers/comedi/comedi_internal.h b/drivers/comedi/comedi_internal.h new file mode 100644 index 000000000..41a3b09f8 --- /dev/null +++ b/drivers/comedi/comedi_internal.h @@ -0,0 +1,86 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _COMEDI_INTERNAL_H +#define _COMEDI_INTERNAL_H + +#include +#include + +/* + * various internal comedi stuff + */ + +struct comedi_buf_map; +struct comedi_devconfig; +struct comedi_device; +struct comedi_insn; +struct comedi_rangeinfo; +struct comedi_subdevice; +struct device; + +int do_rangeinfo_ioctl(struct comedi_device *dev, + struct comedi_rangeinfo *it); +struct comedi_device *comedi_alloc_board_minor(struct device *hardware_device); +void comedi_release_hardware_device(struct device *hardware_device); +int comedi_alloc_subdevice_minor(struct comedi_subdevice *s); +void comedi_free_subdevice_minor(struct comedi_subdevice *s); + +int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s, + unsigned long new_size); +void comedi_buf_reset(struct comedi_subdevice *s); +bool comedi_buf_is_mmapped(struct comedi_subdevice *s); +void comedi_buf_map_get(struct comedi_buf_map *bm); +int comedi_buf_map_put(struct comedi_buf_map *bm); +int comedi_buf_map_access(struct comedi_buf_map *bm, unsigned long offset, + void *buf, int len, int write); +struct comedi_buf_map * +comedi_buf_map_from_subdev_get(struct comedi_subdevice *s); +unsigned int comedi_buf_write_n_available(struct comedi_subdevice *s); +unsigned int comedi_buf_write_n_allocated(struct comedi_subdevice *s); +unsigned int _comedi_buf_write_alloc(struct comedi_subdevice *s, + unsigned int nbytes); +unsigned int _comedi_buf_write_free(struct comedi_subdevice *s, + unsigned int nbytes); +unsigned int _comedi_buf_read_n_available(struct comedi_subdevice *s); +unsigned int _comedi_buf_read_alloc(struct comedi_subdevice *s, + unsigned int nbytes); +unsigned int _comedi_buf_read_free(struct comedi_subdevice *s, + unsigned int nbytes); +void _comedi_inc_scan_progress(struct comedi_subdevice *s, + unsigned int num_bytes); +void _comedi_event(struct comedi_device *dev, struct comedi_subdevice *s); +void comedi_device_cancel_all(struct comedi_device *dev); +bool comedi_can_auto_free_spriv(struct comedi_subdevice *s); + +extern unsigned int comedi_default_buf_size_kb; +extern unsigned int comedi_default_buf_maxsize_kb; + +/* drivers.c */ + +extern struct comedi_driver *comedi_drivers; +extern struct mutex comedi_drivers_list_lock; + +int insn_inval(struct comedi_device *dev, struct comedi_subdevice *s, + struct comedi_insn *insn, unsigned int *data); + +void comedi_device_detach_locked(struct comedi_device *dev); +void comedi_device_detach(struct comedi_device *dev); +int comedi_device_attach(struct comedi_device *dev, + struct comedi_devconfig *it); + +#ifdef CONFIG_PROC_FS + +/* proc.c */ + +void comedi_proc_init(void); +void comedi_proc_cleanup(void); +#else +static inline void comedi_proc_init(void) +{ +} + +static inline void comedi_proc_cleanup(void) +{ +} +#endif + +#endif /* _COMEDI_INTERNAL_H */ -- cgit v1.3.1