[PATCH for-next 11/11] RDMA/rxe: Get rid of pkt resend on err

[Bob Pearson <rpearsonhpe@gmail.com>]

Currently the rxe_driver detects packet drops by ip_local_out()
which occur before the packet is sent on the wire and attempts to
resend them. This is redundant with the usual retry mechanism which
covers packets that get dropped in transit to or from the remote node.

The way this is implemented is not robust since it sets need_req_skb
and waits for the number of local skbs outstanding for this qp to
drop below a low water mark. This is racy since the skb may
be sent to the destructor before the requester can set the
need_req_skb flag. This will cause a deadlock in the send path for
that qp.

This patch removes this mechanism since the normal retry path will
correct the error and resend the packet and it makes no difference
if the packet is dropped locally or later.

Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
---
 drivers/infiniband/sw/rxe/rxe_req.c | 14 ++------------
 1 file changed, 2 insertions(+), 12 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_req.c b/drivers/infiniband/sw/rxe/rxe_req.c
index b217fa94ff03..445650b73b19 100644
--- a/drivers/infiniband/sw/rxe/rxe_req.c
+++ b/drivers/infiniband/sw/rxe/rxe_req.c
@@ -800,18 +800,8 @@ int rxe_requester(struct rxe_qp *qp)
 
 	err = rxe_xmit_packet(qp, &pkt, skb);
 	if (err) {
-		if (err != -EAGAIN) {
-			wqe->status = IB_WC_LOC_QP_OP_ERR;
-			goto err;
-		}
-
-		/* force a delay until the dropped packet is freed and
-		 * the send queue is drained below the low water mark
-		 */
-		qp->need_req_skb = 1;
-
-		rxe_sched_task(&qp->send_task);
-		goto exit;
+		wqe->status = IB_WC_LOC_QP_OP_ERR;
+		goto err;
 	}
 
 	update_wqe_state(qp, wqe, &pkt);
-- 
2.43.0