On Sun, Jul 12, 2020 at 01:53:13PM +0300, Gal Pressman wrote: > On 12/07/2020 13:44, Leon Romanovsky wrote: > > On Thu, Jul 09, 2020 at 09:13:45AM +0300, Gal Pressman wrote: > >> On 08/07/2020 18:44, Leon Romanovsky wrote: > >>> On Wed, Jul 08, 2020 at 03:42:34PM +0300, Gal Pressman wrote: > >>>> On 08/07/2020 12:41, liweihang wrote: > >>>>> Hi all, > >>>>> > >>>>> I'm a little confused about the role of IB_QP_CUR_STATE in the enumeration > >>>>> ib_qp_attr_mask. > >>>>> > >>>>> In manual page of ibv_modify_qp(), comments of cur_qp_state is "Assume this > >>>>> is the current QP state". Why we need to get current qp state from users > >>>>> instead of drivers? > >>>>> > >>>>> For example, why the users are allowed to modify qp from RTR to RTS again > >>>>> even if the qp's state in driver and hardware has already been RTS. > >>>>> > >>>>> I would be appretiate it if someone can help with this. > >>>>> > >>>>> Weihang > >>>>> > >>>> > >>>> Talking about IB_QP_CUR_STATE, I see many drivers filling it in their query QP > >>>> callback although it should only be used in modify operations.. Is there a > >>>> reason not to remove it? > >>> > >>> IBTA section "11.2.5.3 QUERY QUEUE PAIR" has line about IB_QP_CUR_STATE. > >>> It is one of output modifiers. > >>> > >>> Thanks > >>> > >> > >> It says the current QP state should be returned, that's what qp_state field is used for. > >> According to the man pages: > >> > >> libibverbs/man/ibv_query_qp.3: > >> enum ibv_qp_state qp_state; /* Current QP state */ > >> enum ibv_qp_state cur_qp_state; /* Current QP state - irrelevant for ibv_query_qp */ > > > > I don't think that users read it, because ibv_cmd_query_qp() filled > > qp_state to be equal to cur_qp_state from day one. > > Where do you see that? > > I see: > ibv_cmd_query_qp(): > attr->qp_state = resp.qp_state; > attr->cur_qp_state = resp.cur_qp_state; It comes from the the kernel as is and in the kernel: mlx5_ib_query_qp(): 4699 qp_attr->qp_state = qp->state; 4700 qp_attr->cur_qp_state = qp_attr->qp_state; mlx4_ib_query_qp(): 4049 qp->state = to_ib_qp_state(mlx4_state); 4050 qp_attr->qp_state = qp->state; Thanks
