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/siox/siox.h | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) create mode 100644 drivers/siox/siox.h (limited to 'drivers/siox/siox.h') diff --git a/drivers/siox/siox.h b/drivers/siox/siox.h new file mode 100644 index 000000000..513f2c831 --- /dev/null +++ b/drivers/siox/siox.h @@ -0,0 +1,53 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2015-2017 Pengutronix, Uwe Kleine-König + */ +#include +#include +#include + +#define to_siox_master(_dev) container_of((_dev), struct siox_master, dev) +struct siox_master { + /* these fields should be initialized by the driver */ + int busno; + int (*pushpull)(struct siox_master *smaster, + size_t setbuf_len, const u8 setbuf[], + size_t getbuf_len, u8 getbuf[]); + + /* might be initialized by the driver, if 0 it is set to HZ / 40 */ + unsigned long poll_interval; /* in jiffies */ + + /* framework private stuff */ + struct mutex lock; + bool active; + struct module *owner; + struct device dev; + unsigned int num_devices; + struct list_head devices; + + size_t setbuf_len, getbuf_len; + size_t buf_len; + u8 *buf; + u8 status; + + unsigned long last_poll; + struct task_struct *poll_thread; +}; + +static inline void *siox_master_get_devdata(struct siox_master *smaster) +{ + return dev_get_drvdata(&smaster->dev); +} + +struct siox_master *siox_master_alloc(struct device *dev, size_t size); +static inline void siox_master_put(struct siox_master *smaster) +{ + put_device(&smaster->dev); +} + +struct siox_master *devm_siox_master_alloc(struct device *dev, size_t size); + +int siox_master_register(struct siox_master *smaster); +void siox_master_unregister(struct siox_master *smaster); + +int devm_siox_master_register(struct device *dev, struct siox_master *smaster); -- cgit v1.3.1