Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma

Pull inifiniband/rdma updates from Doug Ledford:
 "This is a fairly sizeable set of changes.  I've put them through a
  decent amount of testing prior to sending the pull request due to
  that.

  There are still a few fixups that I know are coming, but I wanted to
  go ahead and get the big, sizable chunk into your hands sooner rather
  than waiting for those last few fixups.

  Of note is the fact that this creates what is intended to be a
  temporary area in the drivers/staging tree specifically for some
  cleanups and additions that are coming for the RDMA stack.  We
  deprecated two drivers (ipath and amso1100) and are waiting to hear
  back if we can deprecate another one (ehca).  We also put Intel's new
  hfi1 driver into this area because it needs to be refactored and a
  transfer library created out of the factored out code, and then it and
  the qib driver and the soft-roce driver should all be modified to use
  that library.

  I expect drivers/staging/rdma to be around for three or four kernel
  releases and then to go away as all of the work is completed and final
  deletions of deprecated drivers are done.

  Summary of changes for 4.3:

   - Create drivers/staging/rdma
   - Move amso1100 driver to staging/rdma and schedule for deletion
   - Move ipath driver to staging/rdma and schedule for deletion
   - Add hfi1 driver to staging/rdma and set TODO for move to regular
     tree
   - Initial support for namespaces to be used on RDMA devices
   - Add RoCE GID table handling to the RDMA core caching code
   - Infrastructure to support handling of devices with differing read
     and write scatter gather capabilities
   - Various iSER updates
   - Kill off unsafe usage of global mr registrations
   - Update SRP driver
   - Misc  mlx4 driver updates
   - Support for the mr_alloc verb
   - Support for a netlink interface between kernel and user space cache
     daemon to speed path record queries and route resolution
   - Ininitial support for safe hot removal of verbs devices"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma: (136 commits)
  IB/ipoib: Suppress warning for send only join failures
  IB/ipoib: Clean up send-only multicast joins
  IB/srp: Fix possible protection fault
  IB/core: Move SM class defines from ib_mad.h to ib_smi.h
  IB/core: Remove unnecessary defines from ib_mad.h
  IB/hfi1: Add PSM2 user space header to header_install
  IB/hfi1: Add CSRs for CONFIG_SDMA_VERBOSITY
  mlx5: Fix incorrect wc pkey_index assignment for GSI messages
  IB/mlx5: avoid destroying a NULL mr in reg_user_mr error flow
  IB/uverbs: reject invalid or unknown opcodes
  IB/cxgb4: Fix if statement in pick_local_ip6adddrs
  IB/sa: Fix rdma netlink message flags
  IB/ucma: HW Device hot-removal support
  IB/mlx4_ib: Disassociate support
  IB/uverbs: Enable device removal when there are active user space applications
  IB/uverbs: Explicitly pass ib_dev to uverbs commands
  IB/uverbs: Fix race between ib_uverbs_open and remove_one
  IB/uverbs: Fix reference counting usage of event files
  IB/core: Make ib_dealloc_pd return void
  IB/srp: Create an insecure all physical rkey only if needed
  ...

1 files changed, 580 insertions, 0 deletions

diff --git a/drivers/staging/rdma/ipath/ipath_ud.c b/drivers/staging/rdma/ipath/ipath_ud.c
new file mode 100644
index 000000000000..e8a2a915251e
--- /dev/null
+++ b/drivers/staging/rdma/ipath/ipath_ud.c
@@ -0,0 +1,580 @@
+/*
+ * Copyright (c) 2006, 2007, 2008 QLogic Corporation. All rights reserved.
+ * Copyright (c) 2005, 2006 PathScale, Inc. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <linux/sched.h>
+#include <rdma/ib_smi.h>
+
+#include "ipath_verbs.h"
+#include "ipath_kernel.h"
+
+/**
+ * ipath_ud_loopback - handle send on loopback QPs
+ * @sqp: the sending QP
+ * @swqe: the send work request
+ *
+ * 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_swqe *swqe)
+{
+	struct ipath_ibdev *dev = to_idev(sqp->ibqp.device);
+	struct ipath_qp *qp;
+	struct ib_ah_attr *ah_attr;
+	unsigned long flags;
+	struct ipath_rq *rq;
+	struct ipath_srq *srq;
+	struct ipath_sge_state rsge;
+	struct ipath_sge *sge;
+	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, swqe->wr.wr.ud.remote_qpn);
+	if (!qp || !(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_RECV_OK)) {
+		dev->n_pkt_drops++;
+		goto done;
+	}
+
+	/*
+	 * Check that the qkey matches (except for QP0, see 9.6.1.4.1).
+	 * Qkeys with the high order bit set mean use the
+	 * qkey from the QP context instead of the WR (see 10.2.5).
+	 */
+	if (unlikely(qp->ibqp.qp_num &&
+		     ((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 drop;
+	}
+
+	/*
+	 * A GRH is expected to precede the data even if not
+	 * present on the wire.
+	 */
+	length = swqe->length;
+	memset(&wc, 0, sizeof wc);
+	wc.byte_len = length + sizeof(struct ib_grh);
+
+	if (swqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
+		wc.wc_flags = IB_WC_WITH_IMM;
+		wc.ex.imm_data = swqe->wr.ex.imm_data;
+	}
+
+	/*
+	 * 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);
+		handler = srq->ibsrq.event_handler;
+		rq = &srq->rq;
+	} else {
+		srq = NULL;
+		handler = NULL;
+		rq = &qp->r_rq;
+	}
+
+	/*
+	 * 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;
+	/* 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);
+	rsge.sg_list = qp->r_ud_sg_list;
+	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) {
+		spin_unlock_irqrestore(&rq->lock, flags);
+		dev->n_pkt_drops++;
+		goto drop;
+	}
+	if (++tail >= rq->size)
+		tail = 0;
+	wq->tail = tail;
+	wc.wr_id = wqe->wr_id;
+	if (handler) {
+		u32 n;
+
+		/*
+		 * validate head pointer value and compute
+		 * the number of remaining WQEs.
+		 */
+		n = wq->head;
+		if (n >= rq->size)
+			n = 0;
+		if (n < tail)
+			n += rq->size - tail;
+		else
+			n -= tail;
+		if (n < srq->limit) {
+			struct ib_event ev;
+
+			srq->limit = 0;
+			spin_unlock_irqrestore(&rq->lock, flags);
+			ev.device = qp->ibqp.device;
+			ev.element.srq = qp->ibqp.srq;
+			ev.event = IB_EVENT_SRQ_LIMIT_REACHED;
+			handler(&ev, srq->ibsrq.srq_context);
+		} else
+			spin_unlock_irqrestore(&rq->lock, flags);
+	} else
+		spin_unlock_irqrestore(&rq->lock, flags);
+
+	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;
+	} else
+		ipath_skip_sge(&rsge, sizeof(struct ib_grh));
+	sge = swqe->sg_list;
+	while (length) {
+		u32 len = sge->length;
+
+		if (len > length)
+			len = length;
+		if (len > sge->sge_length)
+			len = sge->sge_length;
+		BUG_ON(len == 0);
+		ipath_copy_sge(&rsge, sge->vaddr, len);
+		sge->vaddr += len;
+		sge->length -= len;
+		sge->sge_length -= len;
+		if (sge->sge_length == 0) {
+			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)
+					break;
+				sge->n = 0;
+			}
+			sge->vaddr =
+				sge->mr->map[sge->m]->segs[sge->n].vaddr;
+			sge->length =
+				sge->mr->map[sge->m]->segs[sge->n].length;
+		}
+		length -= len;
+	}
+	wc.status = IB_WC_SUCCESS;
+	wc.opcode = IB_WC_RECV;
+	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 |
+		(ah_attr->src_path_bits &
+		 ((1 << dev->dd->ipath_lmc) - 1));
+	wc.sl = ah_attr->sl;
+	wc.dlid_path_bits =
+		ah_attr->dlid & ((1 << dev->dd->ipath_lmc) - 1);
+	wc.port_num = 1;
+	/* Signal completion event if the solicited bit is set. */
+	ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
+		       swqe->wr.send_flags & IB_SEND_SOLICITED);
+drop:
+	if (atomic_dec_and_test(&qp->refcount))
+		wake_up(&qp->wait);
+done:;
+}
+
+/**
+ * ipath_make_ud_req - construct a UD request packet
+ * @qp: the QP
+ *
+ * Return 1 if constructed; otherwise, return 0.
+ */
+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_swqe *wqe;
+	unsigned long flags;
+	u32 nwords;
+	u32 extra_bytes;
+	u32 bth0;
+	u16 lrh0;
+	u16 lid;
+	int ret = 0;
+	int next_cur;
+
+	spin_lock_irqsave(&qp->s_lock, flags);
+
+	if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_NEXT_SEND_OK)) {
+		if (!(ib_ipath_state_ops[qp->state] & IPATH_FLUSH_SEND))
+			goto bail;
+		/* We are in the error state, flush the work request. */
+		if (qp->s_last == qp->s_head)
+			goto bail;
+		/* If DMAs are in progress, we can't flush immediately. */
+		if (atomic_read(&qp->s_dma_busy)) {
+			qp->s_flags |= IPATH_S_WAIT_DMA;
+			goto bail;
+		}
+		wqe = get_swqe_ptr(qp, qp->s_last);
+		ipath_send_complete(qp, wqe, IB_WC_WR_FLUSH_ERR);
+		goto done;
+	}
+
+	if (qp->s_cur == qp->s_head)
+		goto bail;
+
+	wqe = get_swqe_ptr(qp, qp->s_cur);
+	next_cur = qp->s_cur + 1;
+	if (next_cur >= qp->s_size)
+		next_cur = 0;
+
+	/* Construct the header. */
+	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++;
+		else
+			dev->n_unicast_xmit++;
+	} else {
+		dev->n_unicast_xmit++;
+		lid = ah_attr->dlid & ~((1 << dev->dd->ipath_lmc) - 1);
+		if (unlikely(lid == dev->dd->ipath_lid)) {
+			/*
+			 * If DMAs are in progress, we can't generate
+			 * a completion for the loopback packet since
+			 * it would be out of order.
+			 * XXX Instead of waiting, we could queue a
+			 * zero length descriptor so we get a callback.
+			 */
+			if (atomic_read(&qp->s_dma_busy)) {
+				qp->s_flags |= IPATH_S_WAIT_DMA;
+				goto bail;
+			}
+			qp->s_cur = next_cur;
+			spin_unlock_irqrestore(&qp->s_lock, flags);
+			ipath_ud_loopback(qp, wqe);
+			spin_lock_irqsave(&qp->s_lock, flags);
+			ipath_send_complete(qp, wqe, IB_WC_SUCCESS);
+			goto done;
+		}
+	}
+
+	qp->s_cur = next_cur;
+	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;
+	qp->s_cur_size = wqe->length;
+	qp->s_cur_sge = &qp->s_sge;
+	qp->s_dmult = ah_attr->static_rate;
+	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. */
+		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;
+		/*
+		 * 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. */
+		lrh0 = IPATH_LRH_BTH;
+		ohdr = &qp->s_hdr.u.oth;
+	}
+	if (wqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
+		qp->s_hdrwords++;
+		ohdr->u.ud.imm_data = wqe->wr.ex.imm_data;
+		bth0 = IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE << 24;
+	} else
+		bth0 = IB_OPCODE_UD_SEND_ONLY << 24;
+	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(qp->s_hdrwords + nwords +
+					   SIZE_OF_CRC);
+	lid = dev->dd->ipath_lid;
+	if (lid) {
+		lid |= ah_attr->src_path_bits &
+			((1 << dev->dd->ipath_lmc) - 1);
+		qp->s_hdr.lrh[3] = cpu_to_be16(lid);
+	} else
+		qp->s_hdr.lrh[3] = IB_LID_PERMISSIVE;
+	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 :
+		ipath_get_pkey(dev->dd, qp->s_pkey_index);
+	ohdr->bth[0] = cpu_to_be32(bth0);
+	/*
+	 * Use the multicast QP if the destination LID is a multicast LID.
+	 */
+	ohdr->bth[1] = ah_attr->dlid >= IPATH_MULTICAST_LID_BASE &&
+		ah_attr->dlid != IPATH_PERMISSIVE_LID ?
+		cpu_to_be32(IPATH_MULTICAST_QPN) :
+		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)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);
+
+done:
+	ret = 1;
+	goto unlock;
+
+bail:
+	qp->s_flags &= ~IPATH_S_BUSY;
+unlock:
+	spin_unlock_irqrestore(&qp->s_lock, flags);
+	return ret;
+}
+
+/**
+ * ipath_ud_rcv - receive an incoming UD packet
+ * @dev: the device the packet came in on
+ * @hdr: the packet header
+ * @has_grh: true if the packet has a GRH
+ * @data: the packet data
+ * @tlen: the packet length
+ * @qp: the QP the packet came on
+ *
+ * This is called from ipath_qp_rcv() to process an incoming UD packet
+ * for the given QP.
+ * Called at interrupt level.
+ */
+void ipath_ud_rcv(struct ipath_ibdev *dev, struct ipath_ib_header *hdr,
+		  int has_grh, void *data, u32 tlen, struct ipath_qp *qp)
+{
+	struct ipath_other_headers *ohdr;
+	int opcode;
+	u32 hdrsize;
+	u32 pad;
+	struct ib_wc wc;
+	u32 qkey;
+	u32 src_qp;
+	u16 dlid;
+	int header_in_data;
+
+	/* Check for GRH */
+	if (!has_grh) {
+		ohdr = &hdr->u.oth;
+		hdrsize = 8 + 12 + 8;	/* LRH + BTH + DETH */
+		qkey = be32_to_cpu(ohdr->u.ud.deth[0]);
+		src_qp = be32_to_cpu(ohdr->u.ud.deth[1]);
+		header_in_data = 0;
+	} else {
+		ohdr = &hdr->u.l.oth;
+		hdrsize = 8 + 40 + 12 + 8; /* LRH + GRH + BTH + DETH */
+		/*
+		 * The header with GRH is 68 bytes and the core driver sets
+		 * the eager header buffer size to 56 bytes so the last 12
+		 * bytes of the IB header is in the data buffer.
+		 */
+		header_in_data = dev->dd->ipath_rcvhdrentsize == 16;
+		if (header_in_data) {
+			qkey = be32_to_cpu(((__be32 *) data)[1]);
+			src_qp = be32_to_cpu(((__be32 *) data)[2]);
+			data += 12;
+		} else {
+			qkey = be32_to_cpu(ohdr->u.ud.deth[0]);
+			src_qp = be32_to_cpu(ohdr->u.ud.deth[1]);
+		}
+	}
+	src_qp &= IPATH_QPN_MASK;
+
+	/*
+	 * Check that the permissive LID is only used on QP0
+	 * and the QKEY matches (see 9.6.1.4.1 and 9.6.1.5.1).
+	 */
+	if (qp->ibqp.qp_num) {
+		if (unlikely(hdr->lrh[1] == IB_LID_PERMISSIVE ||
+			     hdr->lrh[3] == IB_LID_PERMISSIVE)) {
+			dev->n_pkt_drops++;
+			goto bail;
+		}
+		if (unlikely(qkey != qp->qkey)) {
+			/* XXX OK to lose a count once in a while. */
+			dev->qkey_violations++;
+			dev->n_pkt_drops++;
+			goto bail;
+		}
+	} else if (hdr->lrh[1] == IB_LID_PERMISSIVE ||
+		   hdr->lrh[3] == IB_LID_PERMISSIVE) {
+		struct ib_smp *smp = (struct ib_smp *) data;
+
+		if (smp->mgmt_class != IB_MGMT_CLASS_SUBN_DIRECTED_ROUTE) {
+			dev->n_pkt_drops++;
+			goto bail;
+		}
+	}
+
+	/*
+	 * The opcode is in the low byte when its in network order
+	 * (top byte when in host order).
+	 */
+	opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
+	if (qp->ibqp.qp_num > 1 &&
+	    opcode == IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE) {
+		if (header_in_data) {
+			wc.ex.imm_data = *(__be32 *) data;
+			data += sizeof(__be32);
+		} else
+			wc.ex.imm_data = ohdr->u.ud.imm_data;
+		wc.wc_flags = IB_WC_WITH_IMM;
+		hdrsize += sizeof(u32);
+	} else if (opcode == IB_OPCODE_UD_SEND_ONLY) {
+		wc.ex.imm_data = 0;
+		wc.wc_flags = 0;
+	} else {
+		dev->n_pkt_drops++;
+		goto bail;
+	}
+
+	/* Get the number of bytes the message was padded by. */
+	pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
+	if (unlikely(tlen < (hdrsize + pad + 4))) {
+		/* Drop incomplete packets. */
+		dev->n_pkt_drops++;
+		goto bail;
+	}
+	tlen -= hdrsize + pad + 4;
+
+	/* Drop invalid MAD packets (see 13.5.3.1). */
+	if (unlikely((qp->ibqp.qp_num == 0 &&
+		      (tlen != 256 ||
+		       (be16_to_cpu(hdr->lrh[0]) >> 12) != 15)) ||
+		     (qp->ibqp.qp_num == 1 &&
+		      (tlen != 256 ||
+		       (be16_to_cpu(hdr->lrh[0]) >> 12) == 15)))) {
+		dev->n_pkt_drops++;
+		goto bail;
+	}
+
+	/*
+	 * A GRH is expected to precede the data even if not
+	 * present on the wire.
+	 */
+	wc.byte_len = tlen + sizeof(struct ib_grh);
+
+	/*
+	 * Get the next work request entry to find where to put the data.
+	 */
+	if (qp->r_flags & IPATH_R_REUSE_SGE)
+		qp->r_flags &= ~IPATH_R_REUSE_SGE;
+	else if (!ipath_get_rwqe(qp, 0)) {
+		/*
+		 * Count VL15 packets dropped due to no receive buffer.
+		 * Otherwise, count them as buffer overruns since usually,
+		 * the HW will be able to receive packets even if there are
+		 * no QPs with posted receive buffers.
+		 */
+		if (qp->ibqp.qp_num == 0)
+			dev->n_vl15_dropped++;
+		else
+			dev->rcv_errors++;
+		goto bail;
+	}
+	/* Silently drop packets which are too big. */
+	if (wc.byte_len > qp->r_len) {
+		qp->r_flags |= IPATH_R_REUSE_SGE;
+		dev->n_pkt_drops++;
+		goto bail;
+	}
+	if (has_grh) {
+		ipath_copy_sge(&qp->r_sge, &hdr->u.l.grh,
+			       sizeof(struct ib_grh));
+		wc.wc_flags |= IB_WC_GRH;
+	} else
+		ipath_skip_sge(&qp->r_sge, sizeof(struct ib_grh));
+	ipath_copy_sge(&qp->r_sge, data,
+		       wc.byte_len - sizeof(struct ib_grh));
+	if (!test_and_clear_bit(IPATH_R_WRID_VALID, &qp->r_aflags))
+		goto bail;
+	wc.wr_id = qp->r_wr_id;
+	wc.status = IB_WC_SUCCESS;
+	wc.opcode = IB_WC_RECV;
+	wc.vendor_err = 0;
+	wc.qp = &qp->ibqp;
+	wc.src_qp = src_qp;
+	/* XXX do we know which pkey matched? Only needed for GSI. */
+	wc.pkey_index = 0;
+	wc.slid = be16_to_cpu(hdr->lrh[3]);
+	wc.sl = (be16_to_cpu(hdr->lrh[0]) >> 4) & 0xF;
+	dlid = be16_to_cpu(hdr->lrh[1]);
+	/*
+	 * Save the LMC lower bits if the destination LID is a unicast LID.
+	 */
+	wc.dlid_path_bits = dlid >= IPATH_MULTICAST_LID_BASE ? 0 :
+		dlid & ((1 << dev->dd->ipath_lmc) - 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] &
+			cpu_to_be32(1 << 23)) != 0);
+
+bail:;
+}