[PATCH for-next v3 5/8] RDMA/rxe: Remove qp reference counting in tasks

Bob Pearson
2023-03-04T17:46:52Z

Currently each of the three tasklets requester, completer and
responder in the rxe driver take and release a reference to the
qp argument at the beginning and end of the subroutines. The
caller passing in the qp argument should be responsible for holding
a reference to qp so these are not required. Further doing so
breaks the qp cleanup code in rxe_qp_do_cleanup which calls these
routines after all the references have been dropped so they cannot
drain the packet and work request queues as intended.

In fact if these routines are deferred by calling tasklet_schedule
there is no guarantee that the calling code does have a qp reference.
That is a bug in rxe_task.c which will be fixed later in this series.

Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
---
drivers/infiniband/sw/rxe/rxe_comp.c | 5 -----
drivers/infiniband/sw/rxe/rxe_req.c | 5 -----
drivers/infiniband/sw/rxe/rxe_resp.c | 4 ----
3 files changed, 14 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_comp.c b/drivers/infiniband/sw/rxe/rxe_comp.c
index f7ab0dfe1034..7aa8e90bdfe4 100644
--- a/drivers/infiniband/sw/rxe/rxe_comp.c
+++ b/drivers/infiniband/sw/rxe/rxe_comp.c
@@ -619,9 +619,6 @@ int rxe_completer(struct rxe_qp *qp)
enum comp_state state;
int ret;

- if (!rxe_get(qp))
- return -EAGAIN;
-
if (!qp->valid || qp->comp.state == QP_STATE_ERROR ||
qp->comp.state == QP_STATE_RESET) {
bool notify = qp->valid &&
@@ -824,7 +821,5 @@ int rxe_completer(struct rxe_qp *qp)
out:
if (pkt)
free_pkt(pkt);
- rxe_put(qp);
-
return ret;
}
diff --git a/drivers/infiniband/sw/rxe/rxe_req.c b/drivers/infiniband/sw/rxe/rxe_req.c
index f2dc2d191e16..abc65c54bfd6 100644
--- a/drivers/infiniband/sw/rxe/rxe_req.c
+++ b/drivers/infiniband/sw/rxe/rxe_req.c
@@ -653,9 +653,6 @@ int rxe_requester(struct rxe_qp *qp)
struct rxe_ah *ah;
struct rxe_av *av;

- if (!rxe_get(qp))
- return -EAGAIN;
-
if (unlikely(!qp->valid))
goto exit;

@@ -844,7 +841,5 @@ int rxe_requester(struct rxe_qp *qp)
exit:
ret = -EAGAIN;
out:
- rxe_put(qp);
-
return ret;
}
diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c
index 2f71183449f9..01e3cbea8445 100644
--- a/drivers/infiniband/sw/rxe/rxe_resp.c
+++ b/drivers/infiniband/sw/rxe/rxe_resp.c
@@ -1464,9 +1464,6 @@ int rxe_responder(struct rxe_qp *qp)
struct rxe_pkt_info *pkt = NULL;
int ret;

- if (!rxe_get(qp))
- return -EAGAIN;
-
if (!qp->valid || qp->resp.state == QP_STATE_ERROR ||
qp->resp.state == QP_STATE_RESET) {
bool notify = qp->valid &&
@@ -1658,6 +1655,5 @@ int rxe_responder(struct rxe_qp *qp)
exit:
ret = -EAGAIN;
out:
- rxe_put(qp);
return ret;
}
--
2.37.2