RDMA/core: Add XRC QPs

XRC ("eXtended reliable connected") is an IB transport that provides
better scalability by allowing senders to specify which shared receive
queue (SRQ) should be used to receive a message, which essentially
allows one transport context (QP connection) to serve multiple
destinations (as long as they share an adapter, of course).

XRC communication is between an initiator (INI) QP and a target (TGT)
QP.  Target QPs are associated with SRQs through an XRCD.  An XRC TGT QP
behaves like a receive-only RD QP.  XRC INI QPs behave similarly to RC
QPs, except that work requests posted to an XRC INI QP must specify the
remote SRQ that is the target of the work request.

We define two new QP types for XRC, to distinguish between INI and TGT
QPs, and update the core layer to support XRC QPs.

This patch is derived from work by Jack Morgenstein
<jackm@dev.mellanox.co.il>
Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/infiniband/core/verbs.c

@@ -320,24 +320,44 @@ struct ib_qp *ib_create_qp(struct ib_pd *pd,
 			   struct ib_qp_init_attr *qp_init_attr)
 {
 	struct ib_qp *qp;
+	struct ib_device *device;
 
-	qp = pd->device->create_qp(pd, qp_init_attr, NULL);
+	device = pd ? pd->device : qp_init_attr->xrcd->device;
+	qp = device->create_qp(pd, qp_init_attr, NULL);
 
 	if (!IS_ERR(qp)) {
-		qp->device     	  = pd->device;
-		qp->pd         	  = pd;
-		qp->send_cq    	  = qp_init_attr->send_cq;
-		qp->recv_cq    	  = qp_init_attr->recv_cq;
-		qp->srq	       	  = qp_init_attr->srq;
+		qp->device = device;
+
+		if (qp_init_attr->qp_type == IB_QPT_XRC_TGT) {
+			qp->pd = NULL;
+			qp->send_cq = qp->recv_cq = NULL;
+			qp->srq = NULL;
+			qp->xrcd = qp_init_attr->xrcd;
+			atomic_inc(&qp_init_attr->xrcd->usecnt);
+		} else {
+			if (qp_init_attr->qp_type == IB_QPT_XRC_INI) {
+				qp->recv_cq = NULL;
+				qp->srq = NULL;
+			} else {
+				qp->recv_cq = qp_init_attr->recv_cq;
+				atomic_inc(&qp_init_attr->recv_cq->usecnt);
+				qp->srq = qp_init_attr->srq;
+				if (qp->srq)
+					atomic_inc(&qp_init_attr->srq->usecnt);
+			}
+
+			qp->pd	    = pd;
+			qp->send_cq = qp_init_attr->send_cq;
+			qp->xrcd    = NULL;
+
+			atomic_inc(&pd->usecnt);
+			atomic_inc(&qp_init_attr->send_cq->usecnt);
+		}
+
 		qp->uobject       = NULL;
 		qp->event_handler = qp_init_attr->event_handler;
 		qp->qp_context    = qp_init_attr->qp_context;
 		qp->qp_type	  = qp_init_attr->qp_type;
-		atomic_inc(&pd->usecnt);
-		atomic_inc(&qp_init_attr->send_cq->usecnt);
-		atomic_inc(&qp_init_attr->recv_cq->usecnt);
-		if (qp_init_attr->srq)
-			atomic_inc(&qp_init_attr->srq->usecnt);
 	}
 
 	return qp;
@@ -346,8 +366,8 @@ EXPORT_SYMBOL(ib_create_qp);
 
 static const struct {
 	int			valid;
-	enum ib_qp_attr_mask	req_param[IB_QPT_RAW_ETHERTYPE + 1];
-	enum ib_qp_attr_mask	opt_param[IB_QPT_RAW_ETHERTYPE + 1];
+	enum ib_qp_attr_mask	req_param[IB_QPT_MAX];
+	enum ib_qp_attr_mask	opt_param[IB_QPT_MAX];
 } qp_state_table[IB_QPS_ERR + 1][IB_QPS_ERR + 1] = {
 	[IB_QPS_RESET] = {
 		[IB_QPS_RESET] = { .valid = 1 },
@@ -363,6 +383,12 @@ static const struct {
 				[IB_QPT_RC]  = (IB_QP_PKEY_INDEX		|
 						IB_QP_PORT			|
 						IB_QP_ACCESS_FLAGS),
+				[IB_QPT_XRC_INI] = (IB_QP_PKEY_INDEX		|
+						IB_QP_PORT			|
+						IB_QP_ACCESS_FLAGS),
+				[IB_QPT_XRC_TGT] = (IB_QP_PKEY_INDEX		|
+						IB_QP_PORT			|
+						IB_QP_ACCESS_FLAGS),
 				[IB_QPT_SMI] = (IB_QP_PKEY_INDEX		|
 						IB_QP_QKEY),
 				[IB_QPT_GSI] = (IB_QP_PKEY_INDEX		|
@@ -385,6 +411,12 @@ static const struct {
 				[IB_QPT_RC]  = (IB_QP_PKEY_INDEX		|
 						IB_QP_PORT			|
 						IB_QP_ACCESS_FLAGS),
+				[IB_QPT_XRC_INI] = (IB_QP_PKEY_INDEX		|
+						IB_QP_PORT			|
+						IB_QP_ACCESS_FLAGS),
+				[IB_QPT_XRC_TGT] = (IB_QP_PKEY_INDEX		|
+						IB_QP_PORT			|
+						IB_QP_ACCESS_FLAGS),
 				[IB_QPT_SMI] = (IB_QP_PKEY_INDEX		|
 						IB_QP_QKEY),
 				[IB_QPT_GSI] = (IB_QP_PKEY_INDEX		|
@@ -404,6 +436,16 @@ static const struct {
 						IB_QP_RQ_PSN			|
 						IB_QP_MAX_DEST_RD_ATOMIC	|
 						IB_QP_MIN_RNR_TIMER),
+				[IB_QPT_XRC_INI] = (IB_QP_AV			|
+						IB_QP_PATH_MTU			|
+						IB_QP_DEST_QPN			|
+						IB_QP_RQ_PSN),
+				[IB_QPT_XRC_TGT] = (IB_QP_AV			|
+						IB_QP_PATH_MTU			|
+						IB_QP_DEST_QPN			|
+						IB_QP_RQ_PSN			|
+						IB_QP_MAX_DEST_RD_ATOMIC	|
+						IB_QP_MIN_RNR_TIMER),
 			},
 			.opt_param = {
 				 [IB_QPT_UD]  = (IB_QP_PKEY_INDEX		|
@@ -414,6 +456,12 @@ static const struct {
 				 [IB_QPT_RC]  = (IB_QP_ALT_PATH			|
 						 IB_QP_ACCESS_FLAGS		|
 						 IB_QP_PKEY_INDEX),
+				 [IB_QPT_XRC_INI] = (IB_QP_ALT_PATH		|
+						 IB_QP_ACCESS_FLAGS		|
+						 IB_QP_PKEY_INDEX),
+				 [IB_QPT_XRC_TGT] = (IB_QP_ALT_PATH		|
+						 IB_QP_ACCESS_FLAGS		|
+						 IB_QP_PKEY_INDEX),
 				 [IB_QPT_SMI] = (IB_QP_PKEY_INDEX		|
 						 IB_QP_QKEY),
 				 [IB_QPT_GSI] = (IB_QP_PKEY_INDEX		|
@@ -434,6 +482,13 @@ static const struct {
 						IB_QP_RNR_RETRY			|
 						IB_QP_SQ_PSN			|
 						IB_QP_MAX_QP_RD_ATOMIC),
+				[IB_QPT_XRC_INI] = (IB_QP_TIMEOUT		|
+						IB_QP_RETRY_CNT			|
+						IB_QP_RNR_RETRY			|
+						IB_QP_SQ_PSN			|
+						IB_QP_MAX_QP_RD_ATOMIC),
+				[IB_QPT_XRC_TGT] = (IB_QP_TIMEOUT		|
+						IB_QP_SQ_PSN),
 				[IB_QPT_SMI] = IB_QP_SQ_PSN,
 				[IB_QPT_GSI] = IB_QP_SQ_PSN,
 			},
@@ -449,6 +504,15 @@ static const struct {
 						 IB_QP_ACCESS_FLAGS		|
 						 IB_QP_MIN_RNR_TIMER		|
 						 IB_QP_PATH_MIG_STATE),
+				 [IB_QPT_XRC_INI] = (IB_QP_CUR_STATE		|
+						 IB_QP_ALT_PATH			|
+						 IB_QP_ACCESS_FLAGS		|
+						 IB_QP_PATH_MIG_STATE),
+				 [IB_QPT_XRC_TGT] = (IB_QP_CUR_STATE		|
+						 IB_QP_ALT_PATH			|
+						 IB_QP_ACCESS_FLAGS		|
+						 IB_QP_MIN_RNR_TIMER		|
+						 IB_QP_PATH_MIG_STATE),
 				 [IB_QPT_SMI] = (IB_QP_CUR_STATE		|
 						 IB_QP_QKEY),
 				 [IB_QPT_GSI] = (IB_QP_CUR_STATE		|
@@ -473,6 +537,15 @@ static const struct {
 						IB_QP_ALT_PATH			|
 						IB_QP_PATH_MIG_STATE		|
 						IB_QP_MIN_RNR_TIMER),
+				[IB_QPT_XRC_INI] = (IB_QP_CUR_STATE		|
+						IB_QP_ACCESS_FLAGS		|
+						IB_QP_ALT_PATH			|
+						IB_QP_PATH_MIG_STATE),
+				[IB_QPT_XRC_TGT] = (IB_QP_CUR_STATE		|
+						IB_QP_ACCESS_FLAGS		|
+						IB_QP_ALT_PATH			|
+						IB_QP_PATH_MIG_STATE		|
+						IB_QP_MIN_RNR_TIMER),
 				[IB_QPT_SMI] = (IB_QP_CUR_STATE			|
 						IB_QP_QKEY),
 				[IB_QPT_GSI] = (IB_QP_CUR_STATE			|
@@ -485,6 +558,8 @@ static const struct {
 				[IB_QPT_UD]  = IB_QP_EN_SQD_ASYNC_NOTIFY,
 				[IB_QPT_UC]  = IB_QP_EN_SQD_ASYNC_NOTIFY,
 				[IB_QPT_RC]  = IB_QP_EN_SQD_ASYNC_NOTIFY,
+				[IB_QPT_XRC_INI] = IB_QP_EN_SQD_ASYNC_NOTIFY,
+				[IB_QPT_XRC_TGT] = IB_QP_EN_SQD_ASYNC_NOTIFY, /* ??? */
 				[IB_QPT_SMI] = IB_QP_EN_SQD_ASYNC_NOTIFY,
 				[IB_QPT_GSI] = IB_QP_EN_SQD_ASYNC_NOTIFY
 			}
@@ -507,6 +582,15 @@ static const struct {
 						IB_QP_ACCESS_FLAGS		|
 						IB_QP_MIN_RNR_TIMER		|
 						IB_QP_PATH_MIG_STATE),
+				[IB_QPT_XRC_INI] = (IB_QP_CUR_STATE		|
+						IB_QP_ALT_PATH			|
+						IB_QP_ACCESS_FLAGS		|
+						IB_QP_PATH_MIG_STATE),
+				[IB_QPT_XRC_TGT] = (IB_QP_CUR_STATE		|
+						IB_QP_ALT_PATH			|
+						IB_QP_ACCESS_FLAGS		|
+						IB_QP_MIN_RNR_TIMER		|
+						IB_QP_PATH_MIG_STATE),
 				[IB_QPT_SMI] = (IB_QP_CUR_STATE			|
 						IB_QP_QKEY),
 				[IB_QPT_GSI] = (IB_QP_CUR_STATE			|
@@ -535,6 +619,25 @@ static const struct {
 						IB_QP_PKEY_INDEX		|
 						IB_QP_MIN_RNR_TIMER		|
 						IB_QP_PATH_MIG_STATE),
+				[IB_QPT_XRC_INI] = (IB_QP_PORT			|
+						IB_QP_AV			|
+						IB_QP_TIMEOUT			|
+						IB_QP_RETRY_CNT			|
+						IB_QP_RNR_RETRY			|
+						IB_QP_MAX_QP_RD_ATOMIC		|
+						IB_QP_ALT_PATH			|
+						IB_QP_ACCESS_FLAGS		|
+						IB_QP_PKEY_INDEX		|
+						IB_QP_PATH_MIG_STATE),
+				[IB_QPT_XRC_TGT] = (IB_QP_PORT			|
+						IB_QP_AV			|
+						IB_QP_TIMEOUT			|
+						IB_QP_MAX_DEST_RD_ATOMIC	|
+						IB_QP_ALT_PATH			|
+						IB_QP_ACCESS_FLAGS		|
+						IB_QP_PKEY_INDEX		|
+						IB_QP_MIN_RNR_TIMER		|
+						IB_QP_PATH_MIG_STATE),
 				[IB_QPT_SMI] = (IB_QP_PKEY_INDEX		|
 						IB_QP_QKEY),
 				[IB_QPT_GSI] = (IB_QP_PKEY_INDEX		|
@@ -619,20 +722,27 @@ int ib_destroy_qp(struct ib_qp *qp)
 	struct ib_pd *pd;
 	struct ib_cq *scq, *rcq;
 	struct ib_srq *srq;
+	struct ib_xrcd *xrcd;
 	int ret;
 
-	pd  = qp->pd;
-	scq = qp->send_cq;
-	rcq = qp->recv_cq;
-	srq = qp->srq;
+	pd   = qp->pd;
+	scq  = qp->send_cq;
+	rcq  = qp->recv_cq;
+	srq  = qp->srq;
+	xrcd = qp->xrcd;
 
 	ret = qp->device->destroy_qp(qp);
 	if (!ret) {
-		atomic_dec(&pd->usecnt);
-		atomic_dec(&scq->usecnt);
-		atomic_dec(&rcq->usecnt);
+		if (pd)
+			atomic_dec(&pd->usecnt);
+		if (scq)
+			atomic_dec(&scq->usecnt);
+		if (rcq)
+			atomic_dec(&rcq->usecnt);
 		if (srq)
 			atomic_dec(&srq->usecnt);
+		if (xrcd)
+			atomic_dec(&xrcd->usecnt);
 	}
 
 	return ret;

include/rdma/ib_verbs.h

@@ -579,7 +579,11 @@ enum ib_qp_type {
 	IB_QPT_UC,
 	IB_QPT_UD,
 	IB_QPT_RAW_IPV6,
-	IB_QPT_RAW_ETHERTYPE
+	IB_QPT_RAW_ETHERTYPE,
+	/* Save 8 for RAW_PACKET */
+	IB_QPT_XRC_INI = 9,
+	IB_QPT_XRC_TGT,
+	IB_QPT_MAX
 };
 
 enum ib_qp_create_flags {
@@ -593,6 +597,7 @@ struct ib_qp_init_attr {
 	struct ib_cq	       *send_cq;
 	struct ib_cq	       *recv_cq;
 	struct ib_srq	       *srq;
+	struct ib_xrcd	       *xrcd;     /* XRC TGT QPs only */
 	struct ib_qp_cap	cap;
 	enum ib_sig_type	sq_sig_type;
 	enum ib_qp_type		qp_type;
@@ -784,6 +789,7 @@ struct ib_send_wr {
 			u32				rkey;
 		} fast_reg;
 	} wr;
+	u32			xrc_remote_srq_num;	/* XRC TGT QPs only */
 };
 
 struct ib_recv_wr {
@@ -919,6 +925,7 @@ struct ib_qp {
 	struct ib_cq	       *send_cq;
 	struct ib_cq	       *recv_cq;
 	struct ib_srq	       *srq;
+	struct ib_xrcd	       *xrcd; /* XRC TGT QPs only */
 	struct ib_uobject      *uobject;
 	void                  (*event_handler)(struct ib_event *, void *);
 	void		       *qp_context;