RDMA/hns: Fix missing flush CQE for DWQE

Flush CQE handler has not been called if QP state gets into errored
mode in DWQE path. So, the new added outstanding WQEs will never be
flushed.

It leads to a hung task timeout when using NFS over RDMA:
    __switch_to+0x7c/0xd0
    __schedule+0x350/0x750
    schedule+0x50/0xf0
    schedule_timeout+0x2c8/0x340
    wait_for_common+0xf4/0x2b0
    wait_for_completion+0x20/0x40
    __ib_drain_sq+0x140/0x1d0 [ib_core]
    ib_drain_sq+0x98/0xb0 [ib_core]
    rpcrdma_xprt_disconnect+0x68/0x270 [rpcrdma]
    xprt_rdma_close+0x20/0x60 [rpcrdma]
    xprt_autoclose+0x64/0x1cc [sunrpc]
    process_one_work+0x1d8/0x4e0
    worker_thread+0x154/0x420
    kthread+0x108/0x150
    ret_from_fork+0x10/0x18

Fixes: 01584a5 ("RDMA/hns: Add support of direct wqe")
Signed-off-by: Chengchang Tang <[email protected]>
Signed-off-by: Junxian Huang <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Leon Romanovsky <[email protected]>

Author: Chengchang Tang

drivers/infiniband/hw/hns/hns_roce_hw_v2.c

@@ -670,6 +670,10 @@ static void write_dwqe(struct hns_roce_dev *hr_dev, struct hns_roce_qp *qp,
 #define HNS_ROCE_SL_SHIFT 2
 	struct hns_roce_v2_rc_send_wqe *rc_sq_wqe = wqe;
 
+	if (unlikely(qp->state == IB_QPS_ERR)) {
+		flush_cqe(hr_dev, qp);
+		return;
+	}
 	/* All kinds of DirectWQE have the same header field layout */
 	hr_reg_enable(rc_sq_wqe, RC_SEND_WQE_FLAG);
 	hr_reg_write(rc_sq_wqe, RC_SEND_WQE_DB_SL_L, qp->sl);