/**
* qib_get_rwqe - copy the next RWQE into the QP's RWQE
* @qp: the QP
* @wr_id_only: update qp->r_wr_id only, not qp->r_sge
*
* Return -1 if there is a local error, 0 if no RWQE is available,
* otherwise return 1.
*
* Can be called from interrupt level.
*/
int qib_get_rwqe(struct rvt_qp *qp, int wr_id_only)
{
unsigned long flags;
struct rvt_rq *rq;
struct rvt_rwq *wq;
struct rvt_srq *srq;
struct rvt_rwqe *wqe;
void (*handler)(struct ib_event *, void *);
u32 tail;
int ret;
if (qp->ibqp.srq) {
srq = ibsrq_to_rvtsrq(qp->ibqp.srq);
handler = srq->ibsrq.event_handler;
rq = &srq->rq;
} else {
srq = NULL;
handler = NULL;
rq = &qp->r_rq;
}
spin_lock_irqsave(&rq->lock, flags);
if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK)) {
ret = 0;
goto unlock;
}
wq = rq->wq;
tail = wq->tail;
/* Validate tail before using it since it is user writable. */
if (tail >= rq->size)
tail = 0;
if (unlikely(tail == wq->head)) {
ret = 0;
goto unlock;
}
/* Make sure entry is read after head index is read. */
smp_rmb();
wqe = rvt_get_rwqe_ptr(rq, tail);
/*
* Even though we update the tail index in memory, the verbs
* consumer is not supposed to post more entries until a
* completion is generated.
*/
if (++tail >= rq->size)
tail = 0;
wq->tail = tail;
if (!wr_id_only && !qib_init_sge(qp, wqe)) {
ret = -1;
goto unlock;
}
qp->r_wr_id = wqe->wr_id;
ret = 1;
set_bit(RVT_R_WRID_VALID, &qp->r_aflags);
if (handler) {
u32 n;
/*
* Validate head pointer value and compute
* the number of remaining WQEs.
*/
n = wq->head;
if (n >= rq->size)
n = 0;
if (n < tail)
n += rq->size - tail;
else
n -= tail;
if (n < srq->limit) {
struct ib_event ev;
srq->limit = 0;
spin_unlock_irqrestore(&rq->lock, flags);
ev.device = qp->ibqp.device;
ev.element.srq = qp->ibqp.srq;
ev.event = IB_EVENT_SRQ_LIMIT_REACHED;
handler(&ev, srq->ibsrq.srq_context);
goto bail;
}
}
unlock:
spin_unlock_irqrestore(&rq->lock, flags);
bail:
return ret;
}
int qib_get_rwqe(struct qib_qp *qp, int wr_id_only)
{
unsigned long flags;
struct qib_rq *rq;
struct qib_rwq *wq;
struct qib_srq *srq;
struct qib_rwqe *wqe;
void (*handler)(struct ib_event *, void *);
u32 tail;
int ret;
if (qp->ibqp.srq) {
srq = to_isrq(qp->ibqp.srq);
handler = srq->ibsrq.event_handler;
rq = &srq->rq;
} else {
srq = NULL;
handler = NULL;
rq = &qp->r_rq;
}
spin_lock_irqsave(&rq->lock, flags);
if (!(ib_qib_state_ops[qp->state] & QIB_PROCESS_RECV_OK)) {
ret = 0;
goto unlock;
}
wq = rq->wq;
tail = wq->tail;
if (tail >= rq->size)
tail = 0;
if (unlikely(tail == wq->head)) {
ret = 0;
goto unlock;
}
smp_rmb();
wqe = get_rwqe_ptr(rq, tail);
if (++tail >= rq->size)
tail = 0;
wq->tail = tail;
if (!wr_id_only && !qib_init_sge(qp, wqe)) {
ret = -1;
goto unlock;
}
qp->r_wr_id = wqe->wr_id;
ret = 1;
set_bit(QIB_R_WRID_VALID, &qp->r_aflags);
if (handler) {
u32 n;
n = wq->head;
if (n >= rq->size)
n = 0;
if (n < tail)
n += rq->size - tail;
else
n -= tail;
if (n < srq->limit) {
struct ib_event ev;
srq->limit = 0;
spin_unlock_irqrestore(&rq->lock, flags);
ev.device = qp->ibqp.device;
ev.element.srq = qp->ibqp.srq;
ev.event = IB_EVENT_SRQ_LIMIT_REACHED;
handler(&ev, srq->ibsrq.srq_context);
goto bail;
}
}
unlock:
spin_unlock_irqrestore(&rq->lock, flags);
bail:
return ret;
}