[PATCH 9/20 v2] rdma/uverbs: Export XRC TGT QPs to user space

[PATCH 9/20 v2] rdma/uverbs: Export XRC TGT QPs to user space

[Hefty, Sean]

Allow user space to operate on XRC TGT QPs the same as other
types of QPs, with one notable exception.  Since XRC TGT QPs
may be shared among multiple processes, the XRC TGT QP is
allowed to exist beyond the lifetime of the creating process.

The process that creates the qp is allowed to destroy it, but
if the process exits without destroying the qp, then the qp
will be left bound to the lifetime of the XRCD.

TGT QPs are not associated with CQs or a PD.

Signed-off-by: Sean Hefty <sean.hefty-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
---
 drivers/infiniband/core/uverbs_cmd.c  |  105 +++++++++++++++++++++------------
 drivers/infiniband/core/uverbs_main.c |    8 ++-
 2 files changed, 73 insertions(+), 40 deletions(-)

diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index dee81fc..2787e5d 100644
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -1371,8 +1371,11 @@ ssize_t ib_uverbs_create_qp(struct ib_uverbs_file *file,
 	struct ib_uverbs_create_qp_resp resp;
 	struct ib_udata                 udata;
 	struct ib_uqp_object           *obj;
-	struct ib_pd                   *pd;
-	struct ib_cq                   *scq, *rcq = NULL;
+	struct ib_device	       *device;
+	struct ib_pd                   *pd = NULL;
+	struct ib_xrcd		       *xrcd = NULL;
+	struct ib_uobject	       *uninitialized_var(xrcd_uobj);
+	struct ib_cq                   *scq = NULL, *rcq = NULL;
 	struct ib_srq                  *srq = NULL;
 	struct ib_qp                   *qp;
 	struct ib_qp_init_attr          attr;
@@ -1395,29 +1398,39 @@ ssize_t ib_uverbs_create_qp(struct ib_uverbs_file *file,
 	init_uobj(&obj->uevent.uobject, cmd.user_handle, file->ucontext, &qp_lock_key);
 	down_write(&obj->uevent.uobject.mutex);
 
-	pd  = idr_read_pd(cmd.pd_handle, file->ucontext);
-	scq = idr_read_cq(cmd.send_cq_handle, file->ucontext, 0);
-	if (!pd || !scq ) {
-		ret = -EINVAL;
-		goto err_put;
-	}
-
-	if (cmd.qp_type == IB_QPT_XRC_INI) {
-		cmd.max_recv_wr = cmd.max_recv_sge = 0;
+	if (cmd.qp_type == IB_QPT_XRC_TGT) {
+		xrcd = idr_read_xrcd(cmd.pd_handle, file->ucontext, &xrcd_uobj);
+		if (!xrcd) {
+			ret = -EINVAL;
+			goto err_put;
+		}
+		device = xrcd->device;
 	} else {
-		if (cmd.is_srq) {
-			srq = idr_read_srq(cmd.srq_handle, file->ucontext);
-			if (!srq || srq->srq_type != IB_SRQT_BASIC) {
+		pd  = idr_read_pd(cmd.pd_handle, file->ucontext);
+		scq = idr_read_cq(cmd.send_cq_handle, file->ucontext, 0);
+		if (!pd || !scq ) {
+			ret = -EINVAL;
+			goto err_put;
+		}
+
+		if (cmd.qp_type == IB_QPT_XRC_INI) {
+			cmd.max_recv_wr = cmd.max_recv_sge = 0;
+		} else {
+			if (cmd.is_srq) {
+				srq = idr_read_srq(cmd.srq_handle, file->ucontext);
+				if (!srq || srq->srq_type != IB_SRQT_BASIC) {
+					ret = -EINVAL;
+					goto err_put;
+				}
+			}
+			rcq = (cmd.recv_cq_handle == cmd.send_cq_handle) ?
+			       scq : idr_read_cq(cmd.recv_cq_handle, file->ucontext, 1);
+			if (!rcq) {
 				ret = -EINVAL;
 				goto err_put;
 			}
 		}
-		rcq = (cmd.recv_cq_handle == cmd.send_cq_handle) ?
-		       scq : idr_read_cq(cmd.recv_cq_handle, file->ucontext, 1);
-		if (!rcq) {
-			ret = -EINVAL;
-			goto err_put;
-		}
+		device = pd->device;
 	}
 
 	attr.event_handler = ib_uverbs_qp_event_handler;
@@ -1425,6 +1438,7 @@ ssize_t ib_uverbs_create_qp(struct ib_uverbs_file *file,
 	attr.send_cq       = scq;
 	attr.recv_cq       = rcq;
 	attr.srq           = srq;
+	attr.xrcd	   = xrcd;
 	attr.sq_sig_type   = cmd.sq_sig_all ? IB_SIGNAL_ALL_WR : IB_SIGNAL_REQ_WR;
 	attr.qp_type       = cmd.qp_type;
 	attr.create_flags  = 0;
@@ -1439,27 +1453,33 @@ ssize_t ib_uverbs_create_qp(struct ib_uverbs_file *file,
 	INIT_LIST_HEAD(&obj->uevent.event_list);
 	INIT_LIST_HEAD(&obj->mcast_list);
 
-	qp = pd->device->create_qp(pd, &attr, &udata);
+	if (cmd.qp_type == IB_QPT_XRC_TGT)
+		qp = ib_create_qp(pd, &attr);
+	else
+		qp = device->create_qp(pd, &attr, &udata);
+
 	if (IS_ERR(qp)) {
 		ret = PTR_ERR(qp);
 		goto err_put;
 	}
 
-	qp->device     	  = pd->device;
-	qp->pd         	  = pd;
-	qp->send_cq    	  = attr.send_cq;
-	qp->recv_cq    	  = attr.recv_cq;
-	qp->srq	       	  = attr.srq;
-	qp->uobject       = &obj->uevent.uobject;
-	qp->event_handler = attr.event_handler;
-	qp->qp_context    = attr.qp_context;
-	qp->qp_type	  = attr.qp_type;
-	atomic_inc(&pd->usecnt);
-	atomic_inc(&attr.send_cq->usecnt);
-	if (attr.recv_cq)
-		atomic_inc(&attr.recv_cq->usecnt);
-	if (attr.srq)
-		atomic_inc(&attr.srq->usecnt);
+	if (cmd.qp_type != IB_QPT_XRC_TGT) {
+		qp->device     	  = device;
+		qp->pd         	  = pd;
+		qp->send_cq    	  = attr.send_cq;
+		qp->recv_cq    	  = attr.recv_cq;
+		qp->srq	       	  = attr.srq;
+		qp->event_handler = attr.event_handler;
+		qp->qp_context    = attr.qp_context;
+		qp->qp_type	  = attr.qp_type;
+		atomic_inc(&pd->usecnt);
+		atomic_inc(&attr.send_cq->usecnt);
+		if (attr.recv_cq)
+			atomic_inc(&attr.recv_cq->usecnt);
+		if (attr.srq)
+			atomic_inc(&attr.srq->usecnt);
+	}
+	qp->uobject = &obj->uevent.uobject;
 
 	obj->uevent.uobject.object = qp;
 	ret = idr_add_uobj(&ib_uverbs_qp_idr, &obj->uevent.uobject);
@@ -1481,8 +1501,12 @@ ssize_t ib_uverbs_create_qp(struct ib_uverbs_file *file,
 		goto err_copy;
 	}
 
-	put_pd_read(pd);
-	put_cq_read(scq);
+	if (xrcd)
+		put_xrcd_read(xrcd_uobj);
+	if (pd)
+		put_pd_read(pd);
+	if (scq)
+		put_cq_read(scq);
 	if (rcq && rcq != scq)
 		put_cq_read(rcq);
 	if (srq)
@@ -1505,6 +1529,8 @@ err_destroy:
 	ib_destroy_qp(qp);
 
 err_put:
+	if (xrcd)
+		put_xrcd_read(xrcd_uobj);
 	if (pd)
 		put_pd_read(pd);
 	if (scq)
@@ -1624,6 +1650,9 @@ static int modify_qp_mask(enum ib_qp_type qp_type, int mask)
 	switch (qp_type) {
 	case IB_QPT_XRC_INI:
 		return mask & ~(IB_QP_MAX_DEST_RD_ATOMIC | IB_QP_MIN_RNR_TIMER);
+	case IB_QPT_XRC_TGT:
+		return mask & ~(IB_QP_MAX_QP_RD_ATOMIC | IB_QP_RETRY_CNT |
+				IB_QP_RNR_RETRY);
 	default:
 		return mask;
 	}
diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c
index 6ad221b..0cb69e0 100644
--- a/drivers/infiniband/core/uverbs_main.c
+++ b/drivers/infiniband/core/uverbs_main.c
@@ -206,8 +206,12 @@ static int ib_uverbs_cleanup_ucontext(struct ib_uverbs_file *file,
 			container_of(uobj, struct ib_uqp_object, uevent.uobject);
 
 		idr_remove_uobj(&ib_uverbs_qp_idr, uobj);
-		ib_uverbs_detach_umcast(qp, uqp);
-		ib_destroy_qp(qp);
+		if (qp->qp_type == IB_QPT_XRC_TGT) {
+			ib_release_qp(qp);
+		} else {
+			ib_uverbs_detach_umcast(qp, uqp);
+			ib_destroy_qp(qp);
+		}
 		ib_uverbs_release_uevent(file, &uqp->uevent);
 		kfree(uqp);
 	}


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