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/rpmsg/rpmsg_char.h | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) create mode 100644 drivers/rpmsg/rpmsg_char.h (limited to 'drivers/rpmsg/rpmsg_char.h') diff --git a/drivers/rpmsg/rpmsg_char.h b/drivers/rpmsg/rpmsg_char.h new file mode 100644 index 000000000..117d9cbc5 --- /dev/null +++ b/drivers/rpmsg/rpmsg_char.h @@ -0,0 +1,46 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2022, STMicroelectronics + */ + +#ifndef __RPMSG_CHRDEV_H__ +#define __RPMSG_CHRDEV_H__ + +#if IS_ENABLED(CONFIG_RPMSG_CHAR) +/** + * rpmsg_chrdev_eptdev_create() - register char device based on an endpoint + * @rpdev: prepared rpdev to be used for creating endpoints + * @parent: parent device + * @chinfo: associated endpoint channel information. + * + * This function create a new rpmsg char endpoint device to instantiate a new + * endpoint based on chinfo information. + */ +int rpmsg_chrdev_eptdev_create(struct rpmsg_device *rpdev, struct device *parent, + struct rpmsg_channel_info chinfo); + +/** + * rpmsg_chrdev_eptdev_destroy() - destroy created char device endpoint. + * @data: private data associated to the endpoint device + * + * This function destroys a rpmsg char endpoint device created by the RPMSG_DESTROY_EPT_IOCTL + * control. + */ +int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data); + +#else /*IS_ENABLED(CONFIG_RPMSG_CHAR) */ + +static inline int rpmsg_chrdev_eptdev_create(struct rpmsg_device *rpdev, struct device *parent, + struct rpmsg_channel_info chinfo) +{ + return -ENXIO; +} + +static inline int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data) +{ + return -ENXIO; +} + +#endif /*IS_ENABLED(CONFIG_RPMSG_CHAR) */ + +#endif /*__RPMSG_CHRDEV_H__ */ -- cgit v1.3.1