RDMA//rxe: Optimize send path in rxe_resp.c

Bypass calling check_rkey() in rxe_resp.c for non-rdma messages.

Link: https://lore.kernel.org/r/20230530221334.89432-3-rpearsonhpe@gmail.comSigned-off-by: Bob Pearson <rpearsonhpe@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/sw/rxe/rxe_opcode.h

@@ -91,6 +91,9 @@ enum rxe_hdr_mask {
 	RXE_READ_OR_ATOMIC_MASK	= (RXE_READ_MASK | RXE_ATOMIC_MASK),
 	RXE_WRITE_OR_SEND_MASK	= (RXE_WRITE_MASK | RXE_SEND_MASK),
 	RXE_READ_OR_WRITE_MASK	= (RXE_READ_MASK | RXE_WRITE_MASK),
+	RXE_RDMA_OP_MASK	= (RXE_READ_MASK | RXE_WRITE_MASK |
+				   RXE_ATOMIC_WRITE_MASK | RXE_FLUSH_MASK |
+				   RXE_ATOMIC_MASK),
 };
 
 #define OPCODE_NONE		(-1)

drivers/infiniband/sw/rxe/rxe_resp.c

@@ -387,7 +387,10 @@ static enum resp_states rxe_resp_check_length(struct rxe_qp *qp,
 		}
 	}
 
-	return RESPST_CHK_RKEY;
+	if (pkt->mask & RXE_RDMA_OP_MASK)
+		return RESPST_CHK_RKEY;
+	else
+		return RESPST_EXECUTE;
 }
 
 /* if the reth length field is zero we can assume nothing
@@ -434,6 +437,10 @@ static enum resp_states check_rkey(struct rxe_qp *qp,
 	enum resp_states state;
 	int access = 0;
 
+	/* parse RETH or ATMETH header for first/only packets
+	 * for va, length, rkey, etc. or use current value for
+	 * middle/last packets.
+	 */
 	if (pkt->mask & (RXE_READ_OR_WRITE_MASK | RXE_ATOMIC_WRITE_MASK)) {
 		if (pkt->mask & RXE_RETH_MASK)
 			qp_resp_from_reth(qp, pkt);
@@ -454,7 +461,8 @@ static enum resp_states check_rkey(struct rxe_qp *qp,
 		qp_resp_from_atmeth(qp, pkt);
 		access = IB_ACCESS_REMOTE_ATOMIC;
 	} else {
-		return RESPST_EXECUTE;
+		/* shouldn't happen */
+		WARN_ON(1);
 	}
 
 	/* A zero-byte read or write op is not required to