RDMA/rtrs-clt: Fix recv repost to satisfy ib_drain_rq

On disconnect the client error recovery path calls ib_drain_qp(), which
requires one free RQ slot and that no recv WQEs are posted while the
queue is being drained.

When the server is loaded with always_invalidate=N, the path does not
advertise RTRS_MSG_NEW_RKEY_F.  A client-requested invalidation is then
a standalone SEND_WITH_INV.  The recv completion path did not repost
that WQE; it posted two empty recv WQEs later, when the RDMA-with-IMM
response carried RTRS_IO_RSP_W_INV_IMM.  If the invalidate receive
never arrived, each such response increased RQ occupancy by one until
ib_post_recv() started returning -ENOMEM and __ib_drain_rq() failed
with:

  failed to drain recv queue: -12

Repost one empty recv WQE for every receive completion, including
SEND_WITH_INV completions on the always_invalidate=N path, and only
while the path is still connected so CQ polling cannot race with
ib_drain_qp().  Size IO connection RQs to 2 * queue_depth + 1 to match
the posted recv count and leave the drain slot.

Tested with a synthetic RTRS client flooding unpaired
RTRS_IO_RSP_W_INV_IMM messages; error recovery no longer triggers
__ib_drain_rq() warnings.

Fixes: 6a98d71daea1 ("RDMA/rtrs: client: main functionality")
Signed-off-by: Quanye Yang <quanyeyang@proton.me>
Link: https://lore.kernel.org/linux-rdma/CA+0ovCihE2_pxLimjmmR8NMz4g-ie8dvvq1jmAj-Om33y3Vzfg@mail.gmail.com
Link: https://patch.msgid.link/20261005-rtrs-fix-ib-drain-rq-v2-1-35535a3ed115@proton.me
Tested-by: Quanye Yang <quanyeyang@proton.me>
Reported-by: Farhad Alemi <farhad.alemi@berkeley.edu>
Acked-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>

0 files changed, 0 insertions, 0 deletions