RDMA/irdma: Don't arm the CQ more than two times if no CE for this CQ

[ Upstream commit 10467ce ]

Completion events (CEs) are lost if the application is allowed to arm the
CQ more than two times when no new CE for this CQ has been generated by
the HW.

Check if arming has been done for the CQ and if not, arm the CQ for any
event otherwise promote to arm the CQ for any event only when the last arm
event was solicited.

Fixes: b48c24c ("RDMA/irdma: Implement device supported verb APIs")
Link: https://lore.kernel.org/r/20211201231509.1930-2-shiraz.saleem@intel.com
Signed-off-by: Tatyana Nikolova <tatyana.e.nikolova@intel.com>
Signed-off-by: Shiraz Saleem <shiraz.saleem@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/infiniband/hw/irdma/hw.c

@@ -60,6 +60,8 @@ static void irdma_iwarp_ce_handler(struct irdma_sc_cq *iwcq)
 {
 	struct irdma_cq *cq = iwcq->back_cq;
 
+	if (!cq->user_mode)
+		cq->armed = false;
 	if (cq->ibcq.comp_handler)
 		cq->ibcq.comp_handler(&cq->ibcq, cq->ibcq.cq_context);
 }

drivers/infiniband/hw/irdma/main.h

@@ -541,6 +541,7 @@ int irdma_ah_cqp_op(struct irdma_pci_f *rf, struct irdma_sc_ah *sc_ah, u8 cmd,
 		    void (*callback_fcn)(struct irdma_cqp_request *cqp_request),
 		    void *cb_param);
 void irdma_gsi_ud_qp_ah_cb(struct irdma_cqp_request *cqp_request);
+bool irdma_cq_empty(struct irdma_cq *iwcq);
 int irdma_inetaddr_event(struct notifier_block *notifier, unsigned long event,
 			 void *ptr);
 int irdma_inet6addr_event(struct notifier_block *notifier, unsigned long event,

drivers/infiniband/hw/irdma/utils.c

@@ -2531,3 +2531,18 @@ void irdma_ib_qp_event(struct irdma_qp *iwqp, enum irdma_qp_event_type event)
 	ibevent.element.qp = &iwqp->ibqp;
 	iwqp->ibqp.event_handler(&ibevent, iwqp->ibqp.qp_context);
 }
+
+bool irdma_cq_empty(struct irdma_cq *iwcq)
+{
+	struct irdma_cq_uk *ukcq;
+	u64 qword3;
+	__le64 *cqe;
+	u8 polarity;
+
+	ukcq  = &iwcq->sc_cq.cq_uk;
+	cqe = IRDMA_GET_CURRENT_CQ_ELEM(ukcq);
+	get_64bit_val(cqe, 24, &qword3);
+	polarity = (u8)FIELD_GET(IRDMA_CQ_VALID, qword3);
+
+	return polarity != ukcq->polarity;
+}

drivers/infiniband/hw/irdma/verbs.c

@@ -3604,18 +3604,31 @@ static int irdma_req_notify_cq(struct ib_cq *ibcq,
 	struct irdma_cq *iwcq;
 	struct irdma_cq_uk *ukcq;
 	unsigned long flags;
-	enum irdma_cmpl_notify cq_notify = IRDMA_CQ_COMPL_EVENT;
+	enum irdma_cmpl_notify cq_notify;
+	bool promo_event = false;
+	int ret = 0;
 
+	cq_notify = notify_flags == IB_CQ_SOLICITED ?
+		    IRDMA_CQ_COMPL_SOLICITED : IRDMA_CQ_COMPL_EVENT;
 	iwcq = to_iwcq(ibcq);
 	ukcq = &iwcq->sc_cq.cq_uk;
-	if (notify_flags == IB_CQ_SOLICITED)
-		cq_notify = IRDMA_CQ_COMPL_SOLICITED;
 
 	spin_lock_irqsave(&iwcq->lock, flags);
-	irdma_uk_cq_request_notification(ukcq, cq_notify);
+	/* Only promote to arm the CQ for any event if the last arm event was solicited. */
+	if (iwcq->last_notify == IRDMA_CQ_COMPL_SOLICITED && notify_flags != IB_CQ_SOLICITED)
+		promo_event = true;
+
+	if (!iwcq->armed || promo_event) {
+		iwcq->armed = true;
+		iwcq->last_notify = cq_notify;
+		irdma_uk_cq_request_notification(ukcq, cq_notify);
+	}
+
+	if ((notify_flags & IB_CQ_REPORT_MISSED_EVENTS) && !irdma_cq_empty(iwcq))
+		ret = 1;
 	spin_unlock_irqrestore(&iwcq->lock, flags);
 
-	return 0;
+	return ret;
 }
 
 static int irdma_roce_port_immutable(struct ib_device *ibdev, u32 port_num,

drivers/infiniband/hw/irdma/verbs.h

@@ -110,6 +110,8 @@ struct irdma_cq {
 	u16 cq_size;
 	u16 cq_num;
 	bool user_mode;
+	bool armed;
+	enum irdma_cmpl_notify last_notify;
 	u32 polled_cmpls;
 	u32 cq_mem_size;
 	struct irdma_dma_mem kmem;