RDMA/rxe: Make responder support atomic write on RC service

Make responder process an atomic write request and send a read response
on RC service.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Xiao Yang <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>

drivers/infiniband/sw/rxe/rxe_resp.c

@@ -22,6 +22,7 @@ enum resp_states {
 	RESPST_EXECUTE,
 	RESPST_READ_REPLY,
 	RESPST_ATOMIC_REPLY,
+	RESPST_ATOMIC_WRITE_REPLY,
 	RESPST_COMPLETE,
 	RESPST_ACKNOWLEDGE,
 	RESPST_CLEANUP,
@@ -57,6 +58,7 @@ static char *resp_state_name[] = {
 	[RESPST_EXECUTE]			= "EXECUTE",
 	[RESPST_READ_REPLY]			= "READ_REPLY",
 	[RESPST_ATOMIC_REPLY]			= "ATOMIC_REPLY",
+	[RESPST_ATOMIC_WRITE_REPLY]		= "ATOMIC_WRITE_REPLY",
 	[RESPST_COMPLETE]			= "COMPLETE",
 	[RESPST_ACKNOWLEDGE]			= "ACKNOWLEDGE",
 	[RESPST_CLEANUP]			= "CLEANUP",
@@ -263,7 +265,7 @@ static enum resp_states check_op_valid(struct rxe_qp *qp,
 	case IB_QPT_RC:
 		if (((pkt->mask & RXE_READ_MASK) &&
 		     !(qp->attr.qp_access_flags & IB_ACCESS_REMOTE_READ)) ||
-		    ((pkt->mask & RXE_WRITE_MASK) &&
+		    ((pkt->mask & (RXE_WRITE_MASK | RXE_ATOMIC_WRITE_MASK)) &&
 		     !(qp->attr.qp_access_flags & IB_ACCESS_REMOTE_WRITE)) ||
 		    ((pkt->mask & RXE_ATOMIC_MASK) &&
 		     !(qp->attr.qp_access_flags & IB_ACCESS_REMOTE_ATOMIC))) {
@@ -367,7 +369,7 @@ static enum resp_states check_resource(struct rxe_qp *qp,
 		}
 	}
 
-	if (pkt->mask & RXE_READ_OR_ATOMIC_MASK) {
+	if (pkt->mask & (RXE_READ_OR_ATOMIC_MASK | RXE_ATOMIC_WRITE_MASK)) {
 		/* it is the requesters job to not send
 		 * too many read/atomic ops, we just
 		 * recycle the responder resource queue
@@ -438,7 +440,7 @@ static enum resp_states check_rkey(struct rxe_qp *qp,
 	enum resp_states state;
 	int access;
 
-	if (pkt->mask & RXE_READ_OR_WRITE_MASK) {
+	if (pkt->mask & (RXE_READ_OR_WRITE_MASK | RXE_ATOMIC_WRITE_MASK)) {
 		if (pkt->mask & RXE_RETH_MASK) {
 			qp->resp.va = reth_va(pkt);
 			qp->resp.offset = 0;
@@ -504,7 +506,7 @@ static enum resp_states check_rkey(struct rxe_qp *qp,
 		goto err;
 	}
 
-	if (pkt->mask & RXE_WRITE_MASK)	 {
+	if (pkt->mask & (RXE_WRITE_MASK | RXE_ATOMIC_WRITE_MASK)) {
 		if (resid > mtu) {
 			if (pktlen != mtu || bth_pad(pkt)) {
 				state = RESPST_ERR_LENGTH;
@@ -604,6 +606,7 @@ static struct resp_res *rxe_prepare_res(struct rxe_qp *qp,
 		res->state = rdatm_res_state_new;
 		break;
 	case RXE_ATOMIC_MASK:
+	case RXE_ATOMIC_WRITE_MASK:
 		res->first_psn = pkt->psn;
 		res->last_psn = pkt->psn;
 		res->cur_psn = pkt->psn;
@@ -673,6 +676,55 @@ static enum resp_states atomic_reply(struct rxe_qp *qp,
 	return ret;
 }
 
+static enum resp_states atomic_write_reply(struct rxe_qp *qp,
+						struct rxe_pkt_info *pkt)
+{
+	u64 src, *dst;
+	struct resp_res *res = qp->resp.res;
+	struct rxe_mr *mr = qp->resp.mr;
+	int payload = payload_size(pkt);
+
+	if (!res) {
+		res = rxe_prepare_res(qp, pkt, RXE_ATOMIC_WRITE_MASK);
+		qp->resp.res = res;
+	}
+
+	if (!res->replay) {
+#ifdef CONFIG_64BIT
+		if (mr->state != RXE_MR_STATE_VALID)
+			return RESPST_ERR_RKEY_VIOLATION;
+
+		memcpy(&src, payload_addr(pkt), payload);
+
+		dst = iova_to_vaddr(mr, qp->resp.va + qp->resp.offset, payload);
+		/* check vaddr is 8 bytes aligned. */
+		if (!dst || (uintptr_t)dst & 7)
+			return RESPST_ERR_MISALIGNED_ATOMIC;
+
+		/* Do atomic write after all prior operations have completed */
+		smp_store_release(dst, src);
+
+		/* decrease resp.resid to zero */
+		qp->resp.resid -= sizeof(payload);
+
+		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;
+
+		return RESPST_ACKNOWLEDGE;
+#else
+		return RESPST_ERR_UNSUPPORTED_OPCODE;
+#endif /* CONFIG_64BIT */
+	}
+
+	return RESPST_ACKNOWLEDGE;
+}
+
 static struct sk_buff *prepare_ack_packet(struct rxe_qp *qp,
 					  struct rxe_pkt_info *ack,
 					  int opcode,
@@ -912,6 +964,8 @@ static enum resp_states execute(struct rxe_qp *qp, struct rxe_pkt_info *pkt)
 		return RESPST_READ_REPLY;
 	} else if (pkt->mask & RXE_ATOMIC_MASK) {
 		return RESPST_ATOMIC_REPLY;
+	} else if (pkt->mask & RXE_ATOMIC_WRITE_MASK) {
+		return RESPST_ATOMIC_WRITE_REPLY;
 	} else {
 		/* Unreachable */
 		WARN_ON_ONCE(1);
@@ -1085,6 +1139,19 @@ static int send_atomic_ack(struct rxe_qp *qp, u8 syndrome, u32 psn)
 	return ret;
 }
 
+static int send_read_response_ack(struct rxe_qp *qp, u8 syndrome, u32 psn)
+{
+	int ret = send_common_ack(qp, syndrome, psn,
+			IB_OPCODE_RC_RDMA_READ_RESPONSE_ONLY,
+			"RDMA READ response of length zero ACK");
+
+	/* have to clear this since it is used to trigger
+	 * long read replies
+	 */
+	qp->resp.res = NULL;
+	return ret;
+}
+
 static enum resp_states acknowledge(struct rxe_qp *qp,
 				    struct rxe_pkt_info *pkt)
 {
@@ -1095,6 +1162,8 @@ static enum resp_states acknowledge(struct rxe_qp *qp,
 		send_ack(qp, qp->resp.aeth_syndrome, pkt->psn);
 	else if (pkt->mask & RXE_ATOMIC_MASK)
 		send_atomic_ack(qp, AETH_ACK_UNLIMITED, pkt->psn);
+	else if (pkt->mask & RXE_ATOMIC_WRITE_MASK)
+		send_read_response_ack(qp, AETH_ACK_UNLIMITED, pkt->psn);
 	else if (bth_ack(pkt))
 		send_ack(qp, AETH_ACK_UNLIMITED, pkt->psn);
 
@@ -1206,7 +1275,9 @@ static enum resp_states duplicate_request(struct rxe_qp *qp,
 			res->replay = 1;
 			res->cur_psn = pkt->psn;
 			qp->resp.res = res;
-			rc = RESPST_ATOMIC_REPLY;
+			rc = pkt->mask & RXE_ATOMIC_MASK ?
+					RESPST_ATOMIC_REPLY :
+					RESPST_ATOMIC_WRITE_REPLY;
 			goto out;
 		}
 
@@ -1343,6 +1414,9 @@ int rxe_responder(void *arg)
 		case RESPST_ATOMIC_REPLY:
 			state = atomic_reply(qp, pkt);
 			break;
+		case RESPST_ATOMIC_WRITE_REPLY:
+			state = atomic_write_reply(qp, pkt);
+			break;
 		case RESPST_ACKNOWLEDGE:
 			state = acknowledge(qp, pkt);
 			break;