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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | NOTES | SEE ALSO | COLOPHON |
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io_uring_prep_cancel(3) liburing Manual io_uring_prep_cancel(3)
io_uring_prep_cancel - prepare a cancelation request
#include <liburing.h>
void io_uring_prep_cancel64(struct io_uring_sqe *sqe,
__u64 user_data,
int flags);
void io_uring_prep_cancel(struct io_uring_sqe *sqe,
void *user_data,
int flags);
void io_uring_prep_cancel_fd(struct io_uring_sqe *sqe,
int fd,
unsigned int flags);
The io_uring_prep_cancel(3) function prepares a cancelation
request. The submission queue entry sqe is prepared to cancel an
existing request identified by user_data. For the flags argument,
see below.
io_uring_prep_cancel64(3) is identical to io_uring_prep_cancel(3),
except it takes a 64-bit integer rather than a pointer type.
The cancelation request will attempt to find the previously issued
request identified by user_data and cancel it. The identifier is
what the previously issued request has in their user_data field in
the SQE.
The io_uring_prep_cancel_fd(3) function prepares a cancelation
request. The submission queue entry sqe is prepared to cancel an
existing request that used the file descriptor fd. For the flags
argument, see below.
The cancelation request will attempt to find the previously issued
request that used fd as the file descriptor and cancel it.
By default, the first request matching the criteria given will be
canceled. This can be modified with any of the following flags
passed in:
IORING_ASYNC_CANCEL_ALL
Cancel all requests that match the given criteria, rather
than just canceling the first one found. Available since
5.19.
IORING_ASYNC_CANCEL_FD
Match based on the file descriptor used in the original
request rather than the user_data. This is what
io_uring_prep_cancel_fd(3) sets up. Available since 5.19.
IORING_ASYNC_CANCEL_FD_FIXED
Set in conjunction with IORING_ASYNC_CANCEL_FD , indicating
that the file descriptor given is a direct descriptor
rather than a normal file descriptor. Available since 6.0.
IORING_ASYNC_CANCEL_ANY
Match any request in the ring, regardless of user_data or
file descriptor. Can be used to cancel any pending request
in the ring. Available since 5.19.
IORING_ASYNC_CANCEL_USERDATA
Match request based on the user data field set in the
original request. This is the default lookup key, if no
other key matching has been specified. Available since
6.6.
IORING_ASYNC_CANCEL_OP
Use the original request opcode as the matching key. The
opcopde requested must be set in the sqe len field after
using one of the generic cancel preparation helpers.
Available since 6.6.
None
These are the errors that are reported in the CQE res field. If no
flags are used to cancel multiple requests, 0 is returned on
success. If flags are used to match multiple requests, then a
positive value is returned indicating how many requests were found
and canceled.
-ENOENT
The request identified by user_data could not be located.
This could be because it completed before the cancelation
request was issued, or if an invalid identifier is used.
-EINVAL
One of the fields set in the SQE was invalid.
-EALREADY
The execution state of the request has progressed far
enough that cancelation is no longer possible. This should
normally mean that it will complete shortly, either
successfully, or interrupted due to the cancelation.
Although the cancelation request uses async request syntax, the
kernel side of the cancelation is always run synchronously. It is
guaranteed that a CQE is always generated by the time the cancel
request has been submitted. If the cancelation is successful, the
completion for the request targeted for cancelation will have been
posted by the time submission returns. For -EALREADY it may take a
bit of time to do so. For this case, the caller must wait for the
canceled request to post its completion event.
io_uring_prep_poll_remove(3), io_uring_get_sqe(3),
io_uring_submit(3)
This page is part of the liburing (A library for io_uring)
project. Information about the project can be found at
⟨https://github.com/axboe/liburing⟩. If you have a bug report for
this manual page, send it to io-uring@vger.kernel.org. This page
was obtained from the project's upstream Git repository
⟨https://github.com/axboe/liburing⟩ on 2025-02-02. (At that time,
the date of the most recent commit that was found in the
repository was 2025-01-22.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
liburing-2.2 March 12, 2022 io_uring_prep_cancel(3)
Pages that refer to this page: io_uring_prep_cancel(3), io_uring_prep_cancel64(3), io_uring_prep_cancel_fd(3), io_uring_prep_poll_remove(3), io_uring_register_sync_cancel(3)
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HTML rendering created 2025-02-02 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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