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/tpm/tpm-dev.h | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) create mode 100644 drivers/char/tpm/tpm-dev.h (limited to 'drivers/char/tpm/tpm-dev.h') diff --git a/drivers/char/tpm/tpm-dev.h b/drivers/char/tpm/tpm-dev.h new file mode 100644 index 000000000..f3742bcc7 --- /dev/null +++ b/drivers/char/tpm/tpm-dev.h @@ -0,0 +1,33 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _TPM_DEV_H +#define _TPM_DEV_H + +#include +#include "tpm.h" + +struct file_priv { + struct tpm_chip *chip; + struct tpm_space *space; + + struct mutex buffer_mutex; + struct timer_list user_read_timer; /* user needs to claim result */ + struct work_struct timeout_work; + struct work_struct async_work; + wait_queue_head_t async_wait; + ssize_t response_length; + bool response_read; + bool command_enqueued; + + u8 data_buffer[TPM_BUFSIZE]; +}; + +void tpm_common_open(struct file *file, struct tpm_chip *chip, + struct file_priv *priv, struct tpm_space *space); +ssize_t tpm_common_read(struct file *file, char __user *buf, + size_t size, loff_t *off); +ssize_t tpm_common_write(struct file *file, const char __user *buf, + size_t size, loff_t *off); +__poll_t tpm_common_poll(struct file *file, poll_table *wait); + +void tpm_common_release(struct file *file, struct file_priv *priv); +#endif -- cgit v1.3.1