Re: [PATCH v3 3/3] RDMA/rxe: Add RDMA Atomic Write attribute for rxe device

["yangx.jy@xxxxxxxxxxx" <yangx.jy@xxxxxxxxxxx>]

On 2022/3/25 21:22, Jason Gunthorpe wrote:
> It is not great, but there is not another choice I can see..

Hi Jason,

I plan to only disable the key places by the following change so that 
user cannot use the atomic write:

-----------------------------------------------------------------------------------------------------------

diff --git a/drivers/infiniband/sw/rxe/rxe_req.c 
b/drivers/infiniband/sw/rxe/rxe_req.c
index e2d332a5af0a..7f83b5e39ace 100644
--- a/drivers/infiniband/sw/rxe/rxe_req.c
+++ b/drivers/infiniband/sw/rxe/rxe_req.c
@@ -238,8 +238,10 @@ static int next_opcode_rc(struct rxe_qp *qp, u32 
opcode, int fits)
                         return fits ? 
IB_OPCODE_RC_SEND_ONLY_WITH_INVALIDATE :
                                 IB_OPCODE_RC_SEND_FIRST;

+#ifdef CONFIG_64BIT
         case IB_WR_RDMA_ATOMIC_WRITE:
                 return IB_OPCODE_RC_RDMA_ATOMIC_WRITE;
+#endif /* CONFIG_64BIT */

         case IB_WR_REG_MR:
         case IB_WR_LOCAL_INV:
diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c 
b/drivers/infiniband/sw/rxe/rxe_resp.c
index ddc791b199e2..311ec523fb57 100644
--- a/drivers/infiniband/sw/rxe/rxe_resp.c
+++ b/drivers/infiniband/sw/rxe/rxe_resp.c
@@ -592,6 +592,7 @@ static enum resp_states process_atomic(struct rxe_qp 
*qp,
         return ret;
  }

+#ifdef CONFIG_64BIT
  static enum resp_states process_atomic_write(struct rxe_qp *qp,
                                              struct rxe_pkt_info *pkt)
  {
@@ -613,6 +614,7 @@ static enum resp_states process_atomic_write(struct 
rxe_qp *qp,

         return RESPST_NONE;
  }
+#endif /* CONFIG_64BIT */

  static struct sk_buff *prepare_ack_packet(struct rxe_qp *qp,
                                           struct rxe_pkt_info *pkt,
@@ -871,10 +873,12 @@ static enum resp_states execute(struct rxe_qp *qp, 
struct rxe_pkt_info *pkt)
                 err = process_atomic(qp, pkt);
                 if (err)
                         return err;
+#ifdef CONFIG_64BIT
         } else if (pkt->mask & RXE_ATOMIC_WRITE_MASK) {
                 err = process_atomic_write(qp, pkt);
                 if (err)
                         return err;
+#endif /* CONFIG_64BIT */
         } else {
                 /* Unreachable */
                 WARN_ON_ONCE(1);

-----------------------------------------------------------------------------------------------------------

Best Regards,

Xiao Yang

>
> Jason