IB/ipath: Change UD to queue work requests like RC & UC

The code to post UD sends tried to process work requests at the time
ib_post_send() is called without using a WQE queue.  This was fine as
long as HW resources were available for sending a packet.  This patch
changes UD to be handled more like RC and UC and shares more code.

Signed-off-by: Ralph Campbell <ralph.campbell@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 126 insertions, 246 deletions

diff --git a/drivers/infiniband/hw/ipath/ipath_ud.c b/drivers/infiniband/hw/ipath/ipath_ud.c
index f9a3338a5fb..34c4a0a5be3 100644
--- a/drivers/infiniband/hw/ipath/ipath_ud.c
+++ b/drivers/infiniband/hw/ipath/ipath_ud.c
@@ -36,68 +36,17 @@
 #include "ipath_verbs.h"
 #include "ipath_kernel.h"
 
-static int init_sge(struct ipath_qp *qp, struct ipath_rwqe *wqe,
-		    u32 *lengthp, struct ipath_sge_state *ss)
-{
-	int user = to_ipd(qp->ibqp.pd)->user;
-	int i, j, ret;
-	struct ib_wc wc;
-
-	*lengthp = 0;
-	for (i = j = 0; i < wqe->num_sge; i++) {
-		if (wqe->sg_list[i].length == 0)
-			continue;
-		/* Check LKEY */
-		if ((user && wqe->sg_list[i].lkey == 0) ||
-		    !ipath_lkey_ok(qp, j ? &ss->sg_list[j - 1] : &ss->sge,
-				   &wqe->sg_list[i], IB_ACCESS_LOCAL_WRITE))
-			goto bad_lkey;
-		*lengthp += wqe->sg_list[i].length;
-		j++;
-	}
-	ss->num_sge = j;
-	ret = 1;
-	goto bail;
-
-bad_lkey:
-	wc.wr_id = wqe->wr_id;
-	wc.status = IB_WC_LOC_PROT_ERR;
-	wc.opcode = IB_WC_RECV;
-	wc.vendor_err = 0;
-	wc.byte_len = 0;
-	wc.imm_data = 0;
-	wc.qp = &qp->ibqp;
-	wc.src_qp = 0;
-	wc.wc_flags = 0;
-	wc.pkey_index = 0;
-	wc.slid = 0;
-	wc.sl = 0;
-	wc.dlid_path_bits = 0;
-	wc.port_num = 0;
-	/* Signal solicited completion event. */
-	ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc, 1);
-	ret = 0;
-bail:
-	return ret;
-}
-
 /**
  * ipath_ud_loopback - handle send on loopback QPs
- * @sqp: the QP
- * @ss: the SGE state
- * @length: the length of the data to send
- * @wr: the work request
- * @wc: the work completion entry
+ * @sqp: the sending QP
+ * @swqe: the send work request
  *
- * This is called from ipath_post_ud_send() to forward a WQE addressed
+ * This is called from ipath_make_ud_req() to forward a WQE addressed
  * to the same HCA.
  * Note that the receive interrupt handler may be calling ipath_ud_rcv()
  * while this is being called.
  */
-static void ipath_ud_loopback(struct ipath_qp *sqp,
-			      struct ipath_sge_state *ss,
-			      u32 length, struct ib_send_wr *wr,
-			      struct ib_wc *wc)
+static void ipath_ud_loopback(struct ipath_qp *sqp, struct ipath_swqe *swqe)
 {
 	struct ipath_ibdev *dev = to_idev(sqp->ibqp.device);
 	struct ipath_qp *qp;
@@ -110,12 +59,18 @@ static void ipath_ud_loopback(struct ipath_qp *sqp,
 	struct ipath_rwq *wq;
 	struct ipath_rwqe *wqe;
 	void (*handler)(struct ib_event *, void *);
+	struct ib_wc wc;
 	u32 tail;
 	u32 rlen;
+	u32 length;
 
-	qp = ipath_lookup_qpn(&dev->qp_table, wr->wr.ud.remote_qpn);
-	if (!qp)
-		return;
+	qp = ipath_lookup_qpn(&dev->qp_table, swqe->wr.wr.ud.remote_qpn);
+	if (!qp) {
+		dev->n_pkt_drops++;
+		goto send_comp;
+	}
+
+	rsge.sg_list = NULL;
 
 	/*
 	 * Check that the qkey matches (except for QP0, see 9.6.1.4.1).
@@ -123,39 +78,34 @@ static void ipath_ud_loopback(struct ipath_qp *sqp,
 	 * qkey from the QP context instead of the WR (see 10.2.5).
 	 */
 	if (unlikely(qp->ibqp.qp_num &&
-		     ((int) wr->wr.ud.remote_qkey < 0
-		      ? qp->qkey : wr->wr.ud.remote_qkey) != qp->qkey)) {
+		     ((int) swqe->wr.wr.ud.remote_qkey < 0 ?
+		      sqp->qkey : swqe->wr.wr.ud.remote_qkey) != qp->qkey)) {
 		/* XXX OK to lose a count once in a while. */
 		dev->qkey_violations++;
 		dev->n_pkt_drops++;
-		goto done;
+		goto drop;
 	}
 
 	/*
 	 * A GRH is expected to preceed the data even if not
 	 * present on the wire.
 	 */
-	wc->byte_len = length + sizeof(struct ib_grh);
+	length = swqe->length;
+	wc.byte_len = length + sizeof(struct ib_grh);
 
-	if (wr->opcode == IB_WR_SEND_WITH_IMM) {
-		wc->wc_flags = IB_WC_WITH_IMM;
-		wc->imm_data = wr->imm_data;
+	if (swqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
+		wc.wc_flags = IB_WC_WITH_IMM;
+		wc.imm_data = swqe->wr.imm_data;
 	} else {
-		wc->wc_flags = 0;
-		wc->imm_data = 0;
+		wc.wc_flags = 0;
+		wc.imm_data = 0;
 	}
 
-	if (wr->num_sge > 1) {
-		rsge.sg_list = kmalloc((wr->num_sge - 1) *
-					sizeof(struct ipath_sge),
-				       GFP_ATOMIC);
-	} else
-		rsge.sg_list = NULL;
-
 	/*
-	 * Get the next work request entry to find where to put the data.
-	 * Note that it is safe to drop the lock after changing rq->tail
-	 * since ipath_post_receive() won't fill the empty slot.
+	 * This would be a lot simpler if we could call ipath_get_rwqe()
+	 * but that uses state that the receive interrupt handler uses
+	 * so we would need to lock out receive interrupts while doing
+	 * local loopback.
 	 */
 	if (qp->ibqp.srq) {
 		srq = to_isrq(qp->ibqp.srq);
@@ -167,32 +117,53 @@ static void ipath_ud_loopback(struct ipath_qp *sqp,
 		rq = &qp->r_rq;
 	}
 
+	if (rq->max_sge > 1) {
+		/*
+		 * XXX We could use GFP_KERNEL if ipath_do_send()
+		 * was always called from the tasklet instead of
+		 * from ipath_post_send().
+		 */
+		rsge.sg_list = kmalloc((rq->max_sge - 1) *
+					sizeof(struct ipath_sge),
+				       GFP_ATOMIC);
+		if (!rsge.sg_list) {
+			dev->n_pkt_drops++;
+			goto drop;
+		}
+	}
+
+	/*
+	 * Get the next work request entry to find where to put the data.
+	 * Note that it is safe to drop the lock after changing rq->tail
+	 * since ipath_post_receive() won't fill the empty slot.
+	 */
 	spin_lock_irqsave(&rq->lock, flags);
 	wq = rq->wq;
 	tail = wq->tail;
-	while (1) {
-		if (unlikely(tail == wq->head)) {
-			spin_unlock_irqrestore(&rq->lock, flags);
-			dev->n_pkt_drops++;
-			goto bail_sge;
-		}
-		/* Make sure entry is read after head index is read. */
-		smp_rmb();
-		wqe = get_rwqe_ptr(rq, tail);
-		if (++tail >= rq->size)
-			tail = 0;
-		if (init_sge(qp, wqe, &rlen, &rsge))
-			break;
-		wq->tail = tail;
+	/* Validate tail before using it since it is user writable. */
+	if (tail >= rq->size)
+		tail = 0;
+	if (unlikely(tail == wq->head)) {
+		spin_unlock_irqrestore(&rq->lock, flags);
+		dev->n_pkt_drops++;
+		goto drop;
+	}
+	wqe = get_rwqe_ptr(rq, tail);
+	if (!ipath_init_sge(qp, wqe, &rlen, &rsge)) {
+		spin_unlock_irqrestore(&rq->lock, flags);
+		dev->n_pkt_drops++;
+		goto drop;
 	}
 	/* Silently drop packets which are too big. */
-	if (wc->byte_len > rlen) {
+	if (wc.byte_len > rlen) {
 		spin_unlock_irqrestore(&rq->lock, flags);
 		dev->n_pkt_drops++;
-		goto bail_sge;
+		goto drop;
 	}
+	if (++tail >= rq->size)
+		tail = 0;
 	wq->tail = tail;
-	wc->wr_id = wqe->wr_id;
+	wc.wr_id = wqe->wr_id;
 	if (handler) {
 		u32 n;
 
@@ -221,13 +192,13 @@ static void ipath_ud_loopback(struct ipath_qp *sqp,
 	} else
 		spin_unlock_irqrestore(&rq->lock, flags);
 
-	ah_attr = &to_iah(wr->wr.ud.ah)->attr;
+	ah_attr = &to_iah(swqe->wr.wr.ud.ah)->attr;
 	if (ah_attr->ah_flags & IB_AH_GRH) {
 		ipath_copy_sge(&rsge, &ah_attr->grh, sizeof(struct ib_grh));
-		wc->wc_flags |= IB_WC_GRH;
+		wc.wc_flags |= IB_WC_GRH;
 	} else
 		ipath_skip_sge(&rsge, sizeof(struct ib_grh));
-	sge = &ss->sge;
+	sge = swqe->sg_list;
 	while (length) {
 		u32 len = sge->length;
 
@@ -241,8 +212,8 @@ static void ipath_ud_loopback(struct ipath_qp *sqp,
 		sge->length -= len;
 		sge->sge_length -= len;
 		if (sge->sge_length == 0) {
-			if (--ss->num_sge)
-				*sge = *ss->sg_list++;
+			if (--swqe->wr.num_sge)
+				sge++;
 		} else if (sge->length == 0 && sge->mr != NULL) {
 			if (++sge->n >= IPATH_SEGSZ) {
 				if (++sge->m >= sge->mr->mapsz)
@@ -256,123 +227,60 @@ static void ipath_ud_loopback(struct ipath_qp *sqp,
 		}
 		length -= len;
 	}
-	wc->status = IB_WC_SUCCESS;
-	wc->opcode = IB_WC_RECV;
-	wc->vendor_err = 0;
-	wc->qp = &qp->ibqp;
-	wc->src_qp = sqp->ibqp.qp_num;
+	wc.status = IB_WC_SUCCESS;
+	wc.opcode = IB_WC_RECV;
+	wc.vendor_err = 0;
+	wc.qp = &qp->ibqp;
+	wc.src_qp = sqp->ibqp.qp_num;
 	/* XXX do we know which pkey matched? Only needed for GSI. */
-	wc->pkey_index = 0;
-	wc->slid = dev->dd->ipath_lid |
+	wc.pkey_index = 0;
+	wc.slid = dev->dd->ipath_lid |
 		(ah_attr->src_path_bits &
 		 ((1 << (dev->mkeyprot_resv_lmc & 7)) - 1));
-	wc->sl = ah_attr->sl;
-	wc->dlid_path_bits =
+	wc.sl = ah_attr->sl;
+	wc.dlid_path_bits =
 		ah_attr->dlid & ((1 << (dev->mkeyprot_resv_lmc & 7)) - 1);
+	wc.port_num = 1;
 	/* Signal completion event if the solicited bit is set. */
-	ipath_cq_enter(to_icq(qp->ibqp.recv_cq), wc,
-		       wr->send_flags & IB_SEND_SOLICITED);
-
-bail_sge:
+	ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
+		       swqe->wr.send_flags & IB_SEND_SOLICITED);
+drop:
 	kfree(rsge.sg_list);
-done:
 	if (atomic_dec_and_test(&qp->refcount))
 		wake_up(&qp->wait);
+send_comp:
+	ipath_send_complete(sqp, swqe, IB_WC_SUCCESS);
 }
 
 /**
- * ipath_post_ud_send - post a UD send on QP
+ * ipath_make_ud_req - construct a UD request packet
  * @qp: the QP
- * @wr: the work request
  *
- * Note that we actually send the data as it is posted instead of putting
- * the request into a ring buffer.  If we wanted to use a ring buffer,
- * we would need to save a reference to the destination address in the SWQE.
+ * Return 1 if constructed; otherwise, return 0.
  */
-int ipath_post_ud_send(struct ipath_qp *qp, struct ib_send_wr *wr)
+int ipath_make_ud_req(struct ipath_qp *qp)
 {
 	struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
 	struct ipath_other_headers *ohdr;
 	struct ib_ah_attr *ah_attr;
-	struct ipath_sge_state ss;
-	struct ipath_sge *sg_list;
-	struct ib_wc wc;
-	u32 hwords;
+	struct ipath_swqe *wqe;
 	u32 nwords;
-	u32 len;
 	u32 extra_bytes;
 	u32 bth0;
 	u16 lrh0;
 	u16 lid;
-	int i;
-	int ret;
+	int ret = 0;
 
-	if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_SEND_OK)) {
-		ret = 0;
+	if (unlikely(!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_SEND_OK)))
 		goto bail;
-	}
 
-	if (wr->wr.ud.ah->pd != qp->ibqp.pd) {
-		ret = -EPERM;
+	if (qp->s_cur == qp->s_head)
 		goto bail;
-	}
 
-	/* IB spec says that num_sge == 0 is OK. */
-	if (wr->num_sge > qp->s_max_sge) {
-		ret = -EINVAL;
-		goto bail;
-	}
-
-	if (wr->num_sge > 1) {
-		sg_list = kmalloc((qp->s_max_sge - 1) * sizeof(*sg_list),
-				  GFP_ATOMIC);
-		if (!sg_list) {
-			ret = -ENOMEM;
-			goto bail;
-		}
-	} else
-		sg_list = NULL;
-
-	/* Check the buffer to send. */
-	ss.sg_list = sg_list;
-	ss.sge.mr = NULL;
-	ss.sge.vaddr = NULL;
-	ss.sge.length = 0;
-	ss.sge.sge_length = 0;
-	ss.num_sge = 0;
-	len = 0;
-	for (i = 0; i < wr->num_sge; i++) {
-		/* Check LKEY */
-		if (to_ipd(qp->ibqp.pd)->user && wr->sg_list[i].lkey == 0) {
-			ret = -EINVAL;
-			goto bail;
-		}
-
-		if (wr->sg_list[i].length == 0)
-			continue;
-		if (!ipath_lkey_ok(qp, ss.num_sge ?
-				   sg_list + ss.num_sge - 1 : &ss.sge,
-				   &wr->sg_list[i], 0)) {
-			ret = -EINVAL;
-			goto bail;
-		}
-		len += wr->sg_list[i].length;
-		ss.num_sge++;
-	}
-	/* Check for invalid packet size. */
-	if (len > dev->dd->ipath_ibmtu) {
-		ret = -EINVAL;
-		goto bail;
-	}
-	extra_bytes = (4 - len) & 3;
-	nwords = (len + extra_bytes) >> 2;
+	wqe = get_swqe_ptr(qp, qp->s_cur);
 
 	/* Construct the header. */
-	ah_attr = &to_iah(wr->wr.ud.ah)->attr;
-	if (ah_attr->dlid == 0) {
-		ret = -EINVAL;
-		goto bail;
-	}
+	ah_attr = &to_iah(wqe->wr.wr.ud.ah)->attr;
 	if (ah_attr->dlid >= IPATH_MULTICAST_LID_BASE) {
 		if (ah_attr->dlid != IPATH_PERMISSIVE_LID)
 			dev->n_multicast_xmit++;
@@ -383,64 +291,53 @@ int ipath_post_ud_send(struct ipath_qp *qp, struct ib_send_wr *wr)
 		lid = ah_attr->dlid &
 			~((1 << (dev->mkeyprot_resv_lmc & 7)) - 1);
 		if (unlikely(lid == dev->dd->ipath_lid)) {
-			/*
-			 * Pass in an uninitialized ib_wc to save stack
-			 * space.
-			 */
-			ipath_ud_loopback(qp, &ss, len, wr, &wc);
+			ipath_ud_loopback(qp, wqe);
 			goto done;
 		}
 	}
+
+	extra_bytes = -wqe->length & 3;
+	nwords = (wqe->length + extra_bytes) >> 2;
+
+	/* header size in 32-bit words LRH+BTH+DETH = (8+12+8)/4. */
+	qp->s_hdrwords = 7;
+	if (wqe->wr.opcode == IB_WR_SEND_WITH_IMM)
+		qp->s_hdrwords++;
+	qp->s_cur_size = wqe->length;
+	qp->s_cur_sge = &qp->s_sge;
+	qp->s_wqe = wqe;
+	qp->s_sge.sge = wqe->sg_list[0];
+	qp->s_sge.sg_list = wqe->sg_list + 1;
+	qp->s_sge.num_sge = wqe->wr.num_sge;
+
 	if (ah_attr->ah_flags & IB_AH_GRH) {
 		/* Header size in 32-bit words. */
-		hwords = 17;
+		qp->s_hdrwords += ipath_make_grh(dev, &qp->s_hdr.u.l.grh,
+						 &ah_attr->grh,
+						 qp->s_hdrwords, nwords);
 		lrh0 = IPATH_LRH_GRH;
 		ohdr = &qp->s_hdr.u.l.oth;
-		qp->s_hdr.u.l.grh.version_tclass_flow =
-			cpu_to_be32((6 << 28) |
-				    (ah_attr->grh.traffic_class << 20) |
-				    ah_attr->grh.flow_label);
-		qp->s_hdr.u.l.grh.paylen =
-			cpu_to_be16(((wr->opcode ==
-				      IB_WR_SEND_WITH_IMM ? 6 : 5) +
-				     nwords + SIZE_OF_CRC) << 2);
-		/* next_hdr is defined by C8-7 in ch. 8.4.1 */
-		qp->s_hdr.u.l.grh.next_hdr = 0x1B;
-		qp->s_hdr.u.l.grh.hop_limit = ah_attr->grh.hop_limit;
-		/* The SGID is 32-bit aligned. */
-		qp->s_hdr.u.l.grh.sgid.global.subnet_prefix =
-			dev->gid_prefix;
-		qp->s_hdr.u.l.grh.sgid.global.interface_id =
-			dev->dd->ipath_guid;
-		qp->s_hdr.u.l.grh.dgid = ah_attr->grh.dgid;
 		/*
 		 * Don't worry about sending to locally attached multicast
 		 * QPs.  It is unspecified by the spec. what happens.
 		 */
 	} else {
 		/* Header size in 32-bit words. */
-		hwords = 7;
 		lrh0 = IPATH_LRH_BTH;
 		ohdr = &qp->s_hdr.u.oth;
 	}
-	if (wr->opcode == IB_WR_SEND_WITH_IMM) {
-		ohdr->u.ud.imm_data = wr->imm_data;
-		wc.imm_data = wr->imm_data;
-		hwords += 1;
+	if (wqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
+		ohdr->u.ud.imm_data = wqe->wr.imm_data;
 		bth0 = IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE << 24;
-	} else if (wr->opcode == IB_WR_SEND) {
-		wc.imm_data = 0;
+	} else
 		bth0 = IB_OPCODE_UD_SEND_ONLY << 24;
-	} else {
-		ret = -EINVAL;
-		goto bail;
-	}
 	lrh0 |= ah_attr->sl << 4;
 	if (qp->ibqp.qp_type == IB_QPT_SMI)
 		lrh0 |= 0xF000;	/* Set VL (see ch. 13.5.3.1) */
 	qp->s_hdr.lrh[0] = cpu_to_be16(lrh0);
 	qp->s_hdr.lrh[1] = cpu_to_be16(ah_attr->dlid);	/* DEST LID */
-	qp->s_hdr.lrh[2] = cpu_to_be16(hwords + nwords + SIZE_OF_CRC);
+	qp->s_hdr.lrh[2] = cpu_to_be16(qp->s_hdrwords + nwords +
+					   SIZE_OF_CRC);
 	lid = dev->dd->ipath_lid;
 	if (lid) {
 		lid |= ah_attr->src_path_bits &
@@ -448,7 +345,7 @@ int ipath_post_ud_send(struct ipath_qp *qp, struct ib_send_wr *wr)
 		qp->s_hdr.lrh[3] = cpu_to_be16(lid);
 	} else
 		qp->s_hdr.lrh[3] = IB_LID_PERMISSIVE;
-	if (wr->send_flags & IB_SEND_SOLICITED)
+	if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 		bth0 |= 1 << 23;
 	bth0 |= extra_bytes << 20;
 	bth0 |= qp->ibqp.qp_type == IB_QPT_SMI ? IPATH_DEFAULT_P_KEY :
@@ -460,38 +357,20 @@ int ipath_post_ud_send(struct ipath_qp *qp, struct ib_send_wr *wr)
 	ohdr->bth[1] = ah_attr->dlid >= IPATH_MULTICAST_LID_BASE &&
 		ah_attr->dlid != IPATH_PERMISSIVE_LID ?
 		__constant_cpu_to_be32(IPATH_MULTICAST_QPN) :
-		cpu_to_be32(wr->wr.ud.remote_qpn);
-	/* XXX Could lose a PSN count but not worth locking */
+		cpu_to_be32(wqe->wr.wr.ud.remote_qpn);
 	ohdr->bth[2] = cpu_to_be32(qp->s_next_psn++ & IPATH_PSN_MASK);
 	/*
 	 * Qkeys with the high order bit set mean use the
 	 * qkey from the QP context instead of the WR (see 10.2.5).
 	 */
-	ohdr->u.ud.deth[0] = cpu_to_be32((int)wr->wr.ud.remote_qkey < 0 ?
-					 qp->qkey : wr->wr.ud.remote_qkey);
+	ohdr->u.ud.deth[0] = cpu_to_be32((int)wqe->wr.wr.ud.remote_qkey < 0 ?
+					 qp->qkey : wqe->wr.wr.ud.remote_qkey);
 	ohdr->u.ud.deth[1] = cpu_to_be32(qp->ibqp.qp_num);
-	if (ipath_verbs_send(dev->dd, hwords, (u32 *) &qp->s_hdr,
-			     len, &ss))
-		dev->n_no_piobuf++;
 
 done:
-	/* Queue the completion status entry. */
-	if (!(qp->s_flags & IPATH_S_SIGNAL_REQ_WR) ||
-	    (wr->send_flags & IB_SEND_SIGNALED)) {
-		wc.wr_id = wr->wr_id;
-		wc.status = IB_WC_SUCCESS;
-		wc.vendor_err = 0;
-		wc.opcode = IB_WC_SEND;
-		wc.byte_len = len;
-		wc.qp = &qp->ibqp;
-		wc.src_qp = 0;
-		wc.wc_flags = 0;
-		/* XXX initialize other fields? */
-		ipath_cq_enter(to_icq(qp->ibqp.send_cq), &wc, 0);
-	}
-	kfree(sg_list);
-
-	ret = 0;
+	if (++qp->s_cur >= qp->s_size)
+		qp->s_cur = 0;
+	ret = 1;
 
 bail:
 	return ret;
@@ -673,6 +552,7 @@ void ipath_ud_rcv(struct ipath_ibdev *dev, struct ipath_ib_header *hdr,
 	 */
 	wc.dlid_path_bits = dlid >= IPATH_MULTICAST_LID_BASE ? 0 :
 		dlid & ((1 << (dev->mkeyprot_resv_lmc & 7)) - 1);
+	wc.port_num = 1;
 	/* Signal completion event if the solicited bit is set. */
 	ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
 		       (ohdr->bth[0] &