RDMA/rxe: Add a responder state for atomic reply

Add a responder state for atomic reply similar to read reply and rename
process_atomic() rxe_atomic_reply(). In preparation for merging the normal
and retry atomic responder flows.

Link: https://lore.kernel.org/r/20220606143836.3323-3-rpearsonhpe@gmail.comSigned-off-by: Bob Pearson <rpearsonhpe@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/sw/rxe/rxe_resp.c

@@ -21,6 +21,7 @@ enum resp_states {
 	RESPST_CHK_RKEY,
 	RESPST_EXECUTE,
 	RESPST_READ_REPLY,
+	RESPST_ATOMIC_REPLY,
 	RESPST_COMPLETE,
 	RESPST_ACKNOWLEDGE,
 	RESPST_CLEANUP,
@@ -55,6 +56,7 @@ static char *resp_state_name[] = {
 	[RESPST_CHK_RKEY]			= "CHK_RKEY",
 	[RESPST_EXECUTE]			= "EXECUTE",
 	[RESPST_READ_REPLY]			= "READ_REPLY",
+	[RESPST_ATOMIC_REPLY]			= "ATOMIC_REPLY",
 	[RESPST_COMPLETE]			= "COMPLETE",
 	[RESPST_ACKNOWLEDGE]			= "ACKNOWLEDGE",
 	[RESPST_CLEANUP]			= "CLEANUP",
@@ -552,8 +554,8 @@ static enum resp_states write_data_in(struct rxe_qp *qp,
 /* Guarantee atomicity of atomic operations at the machine level. */
 static DEFINE_SPINLOCK(atomic_ops_lock);
 
-static enum resp_states process_atomic(struct rxe_qp *qp,
-				       struct rxe_pkt_info *pkt)
+static enum resp_states rxe_atomic_reply(struct rxe_qp *qp,
+					 struct rxe_pkt_info *pkt)
 {
 	u64 *vaddr;
 	enum resp_states ret;
@@ -585,7 +587,16 @@ static enum resp_states process_atomic(struct rxe_qp *qp,
 
 	spin_unlock_bh(&atomic_ops_lock);
 
-	ret = RESPST_NONE;
+	qp->resp.msn++;
+
+	/* next expected psn, read handles this separately */
+	qp->resp.psn = (pkt->psn + 1) & BTH_PSN_MASK;
+	qp->resp.ack_psn = qp->resp.psn;
+
+	qp->resp.opcode = pkt->opcode;
+	qp->resp.status = IB_WC_SUCCESS;
+
+	ret = RESPST_ACKNOWLEDGE;
 out:
 	return ret;
 }
@@ -857,9 +868,7 @@ static enum resp_states execute(struct rxe_qp *qp, struct rxe_pkt_info *pkt)
 		qp->resp.msn++;
 		return RESPST_READ_REPLY;
 	} else if (pkt->mask & RXE_ATOMIC_MASK) {
-		err = process_atomic(qp, pkt);
-		if (err)
-			return err;
+		return RESPST_ATOMIC_REPLY;
 	} else {
 		/* Unreachable */
 		WARN_ON_ONCE(1);
@@ -1323,6 +1332,9 @@ int rxe_responder(void *arg)
 		case RESPST_READ_REPLY:
 			state = read_reply(qp, pkt);
 			break;
+		case RESPST_ATOMIC_REPLY:
+			state = rxe_atomic_reply(qp, pkt);
+			break;
 		case RESPST_ACKNOWLEDGE:
 			state = acknowledge(qp, pkt);
 			break;