[openib-general] mthca_modify_qp : acquiring Send/Receive Q locks while modifying qp

[Devesh Sharma]

Hello all,
In mthca_modify_qp function, to read current qp state both send and
receive queues are locked,  why locking both WQ is required? Is there
any dependency on other qp operations?

if (attr_mask & IB_QP_CUR_STATE) {
                cur_state = attr->cur_qp_state;
        } else {
                spin_lock_irq(&qp->sq.lock);
                spin_lock(&qp->rq.lock);
                cur_state = qp->state;
                spin_unlock(&qp->rq.lock);
                spin_unlock_irq(&qp->sq.lock);
        }
Devesh