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NAME | SYNOPSIS | DESCRIPTION | ARGUMENTS | RETURN VALUE | NOTES | SEE ALSO | AUTHORS | COLOPHON |
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mlx5dv_qp_cancel_posted_send_wrs(3) mlx5dv_qp_cancel_posted_send_wrs(3)
mlx5dv_qp_cancel_posted_send_wrs - Cancel all pending send work
requests with supplied WRID in a QP in SQD state
#include <infiniband/mlx5dv.h>
int mlx5dv_qp_cancel_posted_send_wrs(struct mlx5dv_qp_ex *mqp, uint64_t wr_id);
The canceled work requests are replaced with NOPs (no operation),
and will generate good completions according to the signaling
originally requested in the send flags, or “flushed” completions
in case the QP goes to error. A work request can only be canceled
when the QP is in SQD state.
The cancel function is a part of the signature pipelining feature.
The feature allows posting a signature related transfer operation
together with a SEND with a good response to the client.
Normally, the application must wait for the transfer to end, check
the MKEY for errors, and only then send a good or bad response.
However this increases the latency of the good flow of a
transaction.
To enable this feature, a QP must be created with the
MLX5DV_QP_CREATE_SIG_PIPELINING creation flag. Such QP will stop
after a transfer operation that failed signature validation in SQD
state. IBV_EVENT_SQ_DRAINED is generated to inform about the new
state.
The SEND operation that might need to be canceled due to a bad
signature of a previous operation must be posted with the
IBV_SEND_FENCE option in ibv_qp_ex->wr_flags field.
When QP stopped at SQD, it means that at least one WR caused
signature error. It may not be the last WR. It may be that more
than one WRs cause signature errors by the time the QP finally
stopped. It is guaranteed that the QP has stopped somewhere
between the WQE that generated the signature error, and the next
WQE that has IBV_SEND_FENCE on it.
Software must handle the SQD event as described below:
1. Poll everything (polling until 0 once) on the respective CQ,
allowing the discovery of all possible signature errors.
2. Look through all “open” transactions, check related signature
MKEYs using mlx5dv_mkey_check(3), find the one with the
signature error, get a WRID from the operation software context
and handle the failed operation.
3. Cancel the SEND WR by the WRID using
mlx5dv_qp_cancel_posted_send_wrs().
4. Modify the QP back to RTS state.
mqp The QP to investigate, which must be in SQD state.
wr_id The WRID to cancel.
Number of work requests that were canceled, or -errno on error.
A DEVX context should be opened by using mlx5dv_open_device(3).
Must be called with a QP in SQD state.
QP should be created with MLX5DV_QP_CREATE_SIG_PIPELINING creation
flag. Application must listen on QP events, and expect a SQD
event.
mlx5dv_mkey_check(3), mlx5dv_wr_mkey_configure(3),
mlx5dv_wr_set_mkey_sig_block(3), mlx5dv_create_mkey(3),
mlx5dv_destroy_mkey(3)
Oren Duer ⟨oren@nvidia.com⟩
Sergey Gorenko ⟨sergeygo@nvidia.com⟩
This page is part of the rdma-core (RDMA Core Userspace Libraries
and Daemons) project. Information about the project can be found
at ⟨https://github.com/linux-rdma/rdma-core⟩. If you have a bug
report for this manual page, send it to
linux-rdma@vger.kernel.org. This page was obtained from the
project's upstream Git repository
⟨https://github.com/linux-rdma/rdma-core.git⟩ on 2025-08-11. (At
that time, the date of the most recent commit that was found in
the repository was 2025-08-04.) 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
mlx5dv_qp_cancel_posted_send_wrs(3)
Pages that refer to this page: mlx5dv_create_qp(3)
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HTML rendering created 2025-09-06 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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