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Commit 914fcad9 authored by Chuck Lever's avatar Chuck Lever Committed by Anna Schumaker
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xprtrdma: Fix max_send_wr computation 



For FRWR, the computation of max_send_wr is split between
frwr_op_open and rpcrdma_ep_create, which makes it difficult to tell
that the max_send_wr result is currently incorrect if frwr_op_open
has to reduce the credit limit to accommodate a small max_qp_wr.
This is a problem now that extra WRs are needed for backchannel
operations and a drain CQE.

So, refactor the computation so that it is all done in ->ro_open,
and fix the FRWR version of this computation so that it
accommodates HCAs with small max_qp_wr correctly.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent 107c4beb

net/sunrpc/xprtrdma/fmr_ops.c

+22 −0
Original line number Diff line number Diff line
@@ -159,10 +159,32 @@ fmr_op_recover_mr(struct rpcrdma_mr *mr) 
	fmr_op_release_mr(mr);

}



/* On success, sets:

 *	ep->rep_attr.cap.max_send_wr

 *	ep->rep_attr.cap.max_recv_wr

 *	cdata->max_requests

 *	ia->ri_max_segs

 */

static int

fmr_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep,

	    struct rpcrdma_create_data_internal *cdata)

{

	int max_qp_wr;



	max_qp_wr = ia->ri_device->attrs.max_qp_wr;

	max_qp_wr -= RPCRDMA_BACKWARD_WRS;

	max_qp_wr -= 1;

	if (max_qp_wr < RPCRDMA_MIN_SLOT_TABLE)

		return -ENOMEM;

	if (cdata->max_requests > max_qp_wr)

		cdata->max_requests = max_qp_wr;

	ep->rep_attr.cap.max_send_wr = cdata->max_requests;

	ep->rep_attr.cap.max_send_wr += RPCRDMA_BACKWARD_WRS;

	ep->rep_attr.cap.max_send_wr += 1; /* for ib_drain_sq */

	ep->rep_attr.cap.max_recv_wr = cdata->max_requests;

	ep->rep_attr.cap.max_recv_wr += RPCRDMA_BACKWARD_WRS;

	ep->rep_attr.cap.max_recv_wr += 1; /* for ib_drain_rq */



	ia->ri_max_segs = max_t(unsigned int, 1, RPCRDMA_MAX_DATA_SEGS /

				RPCRDMA_MAX_FMR_SGES);

	return 0;

net/sunrpc/xprtrdma/frwr_ops.c

+26 −4
Original line number Diff line number Diff line
@@ -205,12 +205,22 @@ frwr_op_recover_mr(struct rpcrdma_mr *mr) 
	frwr_op_release_mr(mr);

}



/* On success, sets:

 *	ep->rep_attr.cap.max_send_wr

 *	ep->rep_attr.cap.max_recv_wr

 *	cdata->max_requests

 *	ia->ri_max_segs

 *

 * And these FRWR-related fields:

 *	ia->ri_max_frwr_depth

 *	ia->ri_mrtype

 */

static int

frwr_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep,

	     struct rpcrdma_create_data_internal *cdata)

{

	struct ib_device_attr *attrs = &ia->ri_device->attrs;

	int depth, delta;

	int max_qp_wr, depth, delta;



	ia->ri_mrtype = IB_MR_TYPE_MEM_REG;

	if (attrs->device_cap_flags & IB_DEVICE_SG_GAPS_REG)
@@ -244,14 +254,26 @@ frwr_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep, 
		} while (delta > 0);

	}



	ep->rep_attr.cap.max_send_wr *= depth;

	if (ep->rep_attr.cap.max_send_wr > attrs->max_qp_wr) {

		cdata->max_requests = attrs->max_qp_wr / depth;

	max_qp_wr = ia->ri_device->attrs.max_qp_wr;

	max_qp_wr -= RPCRDMA_BACKWARD_WRS;

	max_qp_wr -= 1;

	if (max_qp_wr < RPCRDMA_MIN_SLOT_TABLE)

		return -ENOMEM;

	if (cdata->max_requests > max_qp_wr)

		cdata->max_requests = max_qp_wr;

	ep->rep_attr.cap.max_send_wr = cdata->max_requests * depth;

	if (ep->rep_attr.cap.max_send_wr > max_qp_wr) {

		cdata->max_requests = max_qp_wr / depth;

		if (!cdata->max_requests)

			return -EINVAL;

		ep->rep_attr.cap.max_send_wr = cdata->max_requests *

					       depth;

	}

	ep->rep_attr.cap.max_send_wr += RPCRDMA_BACKWARD_WRS;

	ep->rep_attr.cap.max_send_wr += 1; /* for ib_drain_sq */

	ep->rep_attr.cap.max_recv_wr = cdata->max_requests;

	ep->rep_attr.cap.max_recv_wr += RPCRDMA_BACKWARD_WRS;

	ep->rep_attr.cap.max_recv_wr += 1; /* for ib_drain_rq */



	ia->ri_max_segs = max_t(unsigned int, 1, RPCRDMA_MAX_DATA_SEGS /

				ia->ri_max_frwr_depth);

net/sunrpc/xprtrdma/verbs.c

+4 −20
Original line number Diff line number Diff line
@@ -501,8 +501,8 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia, 
		  struct rpcrdma_create_data_internal *cdata)

{

	struct rpcrdma_connect_private *pmsg = &ep->rep_cm_private;

	unsigned int max_qp_wr, max_sge;

	struct ib_cq *sendcq, *recvcq;

	unsigned int max_sge;

	int rc;



	max_sge = min_t(unsigned int, ia->ri_device->attrs.max_sge,
@@ -513,29 +513,13 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia, 
	}

	ia->ri_max_send_sges = max_sge;



	if (ia->ri_device->attrs.max_qp_wr <= RPCRDMA_BACKWARD_WRS) {

		dprintk("RPC:       %s: insufficient wqe's available\n",

			__func__);

		return -ENOMEM;

	}

	max_qp_wr = ia->ri_device->attrs.max_qp_wr - RPCRDMA_BACKWARD_WRS - 1;



	/* check provider's send/recv wr limits */

	if (cdata->max_requests > max_qp_wr)

		cdata->max_requests = max_qp_wr;

	rc = ia->ri_ops->ro_open(ia, ep, cdata);

	if (rc)

		return rc;



	ep->rep_attr.event_handler = rpcrdma_qp_async_error_upcall;

	ep->rep_attr.qp_context = ep;

	ep->rep_attr.srq = NULL;

	ep->rep_attr.cap.max_send_wr = cdata->max_requests;

	ep->rep_attr.cap.max_send_wr += RPCRDMA_BACKWARD_WRS;

	ep->rep_attr.cap.max_send_wr += 1;	/* drain cqe */

	rc = ia->ri_ops->ro_open(ia, ep, cdata);

	if (rc)

		return rc;

	ep->rep_attr.cap.max_recv_wr = cdata->max_requests;

	ep->rep_attr.cap.max_recv_wr += RPCRDMA_BACKWARD_WRS;

	ep->rep_attr.cap.max_recv_wr += 1;	/* drain cqe */

	ep->rep_attr.cap.max_send_sge = max_sge;

	ep->rep_attr.cap.max_recv_sge = 1;

	ep->rep_attr.cap.max_inline_data = 0;