drivers/infiniband/sw/rxe/rxe_req.c - kernel/msm-4.19 - Gitiles

 /*
  * Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
  * Copyright (c) 2015 System Fabric Works, 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/skbuff.h>
 #include <crypto/hash.h>

 #include "rxe.h"
 #include "rxe_loc.h"
 #include "rxe_queue.h"

 static int next_opcode(struct rxe_qp *qp, struct rxe_send_wqe *wqe,
 		       u32 opcode);

 static inline void retry_first_write_send(struct rxe_qp *qp,
 					  struct rxe_send_wqe *wqe,
 					  unsigned int mask, int npsn)
 {
 	int i;

 	for (i = 0; i < npsn; i++) {
 		int to_send = (wqe->dma.resid > qp->mtu) ?
 				qp->mtu : wqe->dma.resid;

 		qp->req.opcode = next_opcode(qp, wqe,
 					     wqe->wr.opcode);

 		if (wqe->wr.send_flags & IB_SEND_INLINE) {
 			wqe->dma.resid -= to_send;
 			wqe->dma.sge_offset += to_send;
 		} else {
 			advance_dma_data(&wqe->dma, to_send);
 		}
 		if (mask & WR_WRITE_MASK)
 			wqe->iova += qp->mtu;
 	}
 }

 static void req_retry(struct rxe_qp *qp)
 {
 	struct rxe_send_wqe *wqe;
 	unsigned int wqe_index;
 	unsigned int mask;
 	int npsn;
 	int first = 1;

 	wqe = queue_head(qp->sq.queue);
 	npsn = (qp->comp.psn - wqe->first_psn) & BTH_PSN_MASK;

 	qp->req.wqe_index	= consumer_index(qp->sq.queue);
 	qp->req.psn		= qp->comp.psn;
 	qp->req.opcode		= -1;

 	for (wqe_index = consumer_index(qp->sq.queue);
 		wqe_index != producer_index(qp->sq.queue);
 		wqe_index = next_index(qp->sq.queue, wqe_index)) {
 		wqe = addr_from_index(qp->sq.queue, wqe_index);
 		mask = wr_opcode_mask(wqe->wr.opcode, qp);

 		if (wqe->state == wqe_state_posted)
 			break;

 		if (wqe->state == wqe_state_done)
 			continue;

 		wqe->iova = (mask & WR_ATOMIC_MASK) ?
 			     wqe->wr.wr.atomic.remote_addr :
 			     (mask & WR_READ_OR_WRITE_MASK) ?
 			     wqe->wr.wr.rdma.remote_addr :
 			     0;

 		if (!first || (mask & WR_READ_MASK) == 0) {
 			wqe->dma.resid = wqe->dma.length;
 			wqe->dma.cur_sge = 0;
 			wqe->dma.sge_offset = 0;
 		}

 		if (first) {
 			first = 0;

 			if (mask & WR_WRITE_OR_SEND_MASK)
 				retry_first_write_send(qp, wqe, mask, npsn);

 			if (mask & WR_READ_MASK)
 				wqe->iova += npsn * qp->mtu;
 		}

 		wqe->state = wqe_state_posted;
 	}
 }

 void rnr_nak_timer(struct timer_list *t)
 {
 	struct rxe_qp *qp = from_timer(qp, t, rnr_nak_timer);

 	pr_debug("qp#%d rnr nak timer fired\n", qp_num(qp));
 	rxe_run_task(&qp->req.task, 1);
 }

 static struct rxe_send_wqe *req_next_wqe(struct rxe_qp *qp)
 {
 	struct rxe_send_wqe *wqe = queue_head(qp->sq.queue);
 	unsigned long flags;

 	if (unlikely(qp->req.state == QP_STATE_DRAIN)) {
 		/* check to see if we are drained;
 		 * state_lock used by requester and completer
 		 */
 		spin_lock_irqsave(&qp->state_lock, flags);
 		do {
 			if (qp->req.state != QP_STATE_DRAIN) {
 				/* comp just finished */
 				spin_unlock_irqrestore(&qp->state_lock,
 						       flags);
 				break;
 			}

 			if (wqe && ((qp->req.wqe_index !=
 				consumer_index(qp->sq.queue)) ||
 				(wqe->state != wqe_state_posted))) {
 				/* comp not done yet */
 				spin_unlock_irqrestore(&qp->state_lock,
 						       flags);
 				break;
 			}

 			qp->req.state = QP_STATE_DRAINED;
 			spin_unlock_irqrestore(&qp->state_lock, flags);

 			if (qp->ibqp.event_handler) {
 				struct ib_event ev;

 				ev.device = qp->ibqp.device;
 				ev.element.qp = &qp->ibqp;
 				ev.event = IB_EVENT_SQ_DRAINED;
 				qp->ibqp.event_handler(&ev,
 					qp->ibqp.qp_context);
 			}
 		} while (0);
 	}

 	if (qp->req.wqe_index == producer_index(qp->sq.queue))
 		return NULL;

 	wqe = addr_from_index(qp->sq.queue, qp->req.wqe_index);

 	if (unlikely((qp->req.state == QP_STATE_DRAIN ||
 		      qp->req.state == QP_STATE_DRAINED) &&
 		     (wqe->state != wqe_state_processing)))
 		return NULL;

 	if (unlikely((wqe->wr.send_flags & IB_SEND_FENCE) &&
 		     (qp->req.wqe_index != consumer_index(qp->sq.queue)))) {
 		qp->req.wait_fence = 1;
 		return NULL;
 	}

 	wqe->mask = wr_opcode_mask(wqe->wr.opcode, qp);
 	return wqe;
 }

 static int next_opcode_rc(struct rxe_qp *qp, u32 opcode, int fits)
 {
 	switch (opcode) {
 	case IB_WR_RDMA_WRITE:
 		if (qp->req.opcode == IB_OPCODE_RC_RDMA_WRITE_FIRST ||
 		    qp->req.opcode == IB_OPCODE_RC_RDMA_WRITE_MIDDLE)
 			return fits ?
 				IB_OPCODE_RC_RDMA_WRITE_LAST :
 				IB_OPCODE_RC_RDMA_WRITE_MIDDLE;
 		else
 			return fits ?
 				IB_OPCODE_RC_RDMA_WRITE_ONLY :
 				IB_OPCODE_RC_RDMA_WRITE_FIRST;

 	case IB_WR_RDMA_WRITE_WITH_IMM:
 		if (qp->req.opcode == IB_OPCODE_RC_RDMA_WRITE_FIRST ||
 		    qp->req.opcode == IB_OPCODE_RC_RDMA_WRITE_MIDDLE)
 			return fits ?
 				IB_OPCODE_RC_RDMA_WRITE_LAST_WITH_IMMEDIATE :
 				IB_OPCODE_RC_RDMA_WRITE_MIDDLE;
 		else
 			return fits ?
 				IB_OPCODE_RC_RDMA_WRITE_ONLY_WITH_IMMEDIATE :
 				IB_OPCODE_RC_RDMA_WRITE_FIRST;

 	case IB_WR_SEND:
 		if (qp->req.opcode == IB_OPCODE_RC_SEND_FIRST ||
 		    qp->req.opcode == IB_OPCODE_RC_SEND_MIDDLE)
 			return fits ?
 				IB_OPCODE_RC_SEND_LAST :
 				IB_OPCODE_RC_SEND_MIDDLE;
 		else
 			return fits ?
 				IB_OPCODE_RC_SEND_ONLY :
 				IB_OPCODE_RC_SEND_FIRST;

 	case IB_WR_SEND_WITH_IMM:
 		if (qp->req.opcode == IB_OPCODE_RC_SEND_FIRST ||
 		    qp->req.opcode == IB_OPCODE_RC_SEND_MIDDLE)
 			return fits ?
 				IB_OPCODE_RC_SEND_LAST_WITH_IMMEDIATE :
 				IB_OPCODE_RC_SEND_MIDDLE;
 		else
 			return fits ?
 				IB_OPCODE_RC_SEND_ONLY_WITH_IMMEDIATE :
 				IB_OPCODE_RC_SEND_FIRST;

 	case IB_WR_RDMA_READ:
 		return IB_OPCODE_RC_RDMA_READ_REQUEST;

 	case IB_WR_ATOMIC_CMP_AND_SWP:
 		return IB_OPCODE_RC_COMPARE_SWAP;

 	case IB_WR_ATOMIC_FETCH_AND_ADD:
 		return IB_OPCODE_RC_FETCH_ADD;

 	case IB_WR_SEND_WITH_INV:
 		if (qp->req.opcode == IB_OPCODE_RC_SEND_FIRST ||
 		    qp->req.opcode == IB_OPCODE_RC_SEND_MIDDLE)
 			return fits ? IB_OPCODE_RC_SEND_LAST_WITH_INVALIDATE :
 				IB_OPCODE_RC_SEND_MIDDLE;
 		else
 			return fits ? IB_OPCODE_RC_SEND_ONLY_WITH_INVALIDATE :
 				IB_OPCODE_RC_SEND_FIRST;
 	case IB_WR_REG_MR:
 	case IB_WR_LOCAL_INV:
 		return opcode;
 	}

 	return -EINVAL;
 }

 static int next_opcode_uc(struct rxe_qp *qp, u32 opcode, int fits)
 {
 	switch (opcode) {
 	case IB_WR_RDMA_WRITE:
 		if (qp->req.opcode == IB_OPCODE_UC_RDMA_WRITE_FIRST ||
 		    qp->req.opcode == IB_OPCODE_UC_RDMA_WRITE_MIDDLE)
 			return fits ?
 				IB_OPCODE_UC_RDMA_WRITE_LAST :
 				IB_OPCODE_UC_RDMA_WRITE_MIDDLE;
 		else
 			return fits ?
 				IB_OPCODE_UC_RDMA_WRITE_ONLY :
 				IB_OPCODE_UC_RDMA_WRITE_FIRST;

 	case IB_WR_RDMA_WRITE_WITH_IMM:
 		if (qp->req.opcode == IB_OPCODE_UC_RDMA_WRITE_FIRST ||
 		    qp->req.opcode == IB_OPCODE_UC_RDMA_WRITE_MIDDLE)
 			return fits ?
 				IB_OPCODE_UC_RDMA_WRITE_LAST_WITH_IMMEDIATE :
 				IB_OPCODE_UC_RDMA_WRITE_MIDDLE;
 		else
 			return fits ?
 				IB_OPCODE_UC_RDMA_WRITE_ONLY_WITH_IMMEDIATE :
 				IB_OPCODE_UC_RDMA_WRITE_FIRST;

 	case IB_WR_SEND:
 		if (qp->req.opcode == IB_OPCODE_UC_SEND_FIRST ||
 		    qp->req.opcode == IB_OPCODE_UC_SEND_MIDDLE)
 			return fits ?
 				IB_OPCODE_UC_SEND_LAST :
 				IB_OPCODE_UC_SEND_MIDDLE;
 		else
 			return fits ?
 				IB_OPCODE_UC_SEND_ONLY :
 				IB_OPCODE_UC_SEND_FIRST;

 	case IB_WR_SEND_WITH_IMM:
 		if (qp->req.opcode == IB_OPCODE_UC_SEND_FIRST ||
 		    qp->req.opcode == IB_OPCODE_UC_SEND_MIDDLE)
 			return fits ?
 				IB_OPCODE_UC_SEND_LAST_WITH_IMMEDIATE :
 				IB_OPCODE_UC_SEND_MIDDLE;
 		else
 			return fits ?
 				IB_OPCODE_UC_SEND_ONLY_WITH_IMMEDIATE :
 				IB_OPCODE_UC_SEND_FIRST;
 	}

 	return -EINVAL;
 }

 static int next_opcode(struct rxe_qp *qp, struct rxe_send_wqe *wqe,
 		       u32 opcode)
 {
 	int fits = (wqe->dma.resid <= qp->mtu);

 	switch (qp_type(qp)) {
 	case IB_QPT_RC:
 		return next_opcode_rc(qp, opcode, fits);

 	case IB_QPT_UC:
 		return next_opcode_uc(qp, opcode, fits);

 	case IB_QPT_SMI:
 	case IB_QPT_UD:
 	case IB_QPT_GSI:
 		switch (opcode) {
 		case IB_WR_SEND:
 			return IB_OPCODE_UD_SEND_ONLY;

 		case IB_WR_SEND_WITH_IMM:
 			return IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE;
 		}
 		break;

 	default:
 		break;
 	}

 	return -EINVAL;
 }

 static inline int check_init_depth(struct rxe_qp *qp, struct rxe_send_wqe *wqe)
 {
 	int depth;

 	if (wqe->has_rd_atomic)
 		return 0;

 	qp->req.need_rd_atomic = 1;
 	depth = atomic_dec_return(&qp->req.rd_atomic);

 	if (depth >= 0) {
 		qp->req.need_rd_atomic = 0;
 		wqe->has_rd_atomic = 1;
 		return 0;
 	}

 	atomic_inc(&qp->req.rd_atomic);
 	return -EAGAIN;
 }

 static inline int get_mtu(struct rxe_qp *qp)
 {
 	struct rxe_dev *rxe = to_rdev(qp->ibqp.device);

 	if ((qp_type(qp) == IB_QPT_RC) || (qp_type(qp) == IB_QPT_UC))
 		return qp->mtu;

 	return rxe->port.mtu_cap;
 }

 static struct sk_buff *init_req_packet(struct rxe_qp *qp,
 				       struct rxe_send_wqe *wqe,
 				       int opcode, int payload,
 				       struct rxe_pkt_info *pkt)
 {
 	struct rxe_dev		*rxe = to_rdev(qp->ibqp.device);
 	struct rxe_port		*port = &rxe->port;
 	struct sk_buff		*skb;
 	struct rxe_send_wr	*ibwr = &wqe->wr;
 	struct rxe_av		*av;
 	int			pad = (-payload) & 0x3;
 	int			paylen;
 	int			solicited;
 	u16			pkey;
 	u32			qp_num;
 	int			ack_req;

 	/* length from start of bth to end of icrc */
 	paylen = rxe_opcode[opcode].length + payload + pad + RXE_ICRC_SIZE;

 	/* pkt->hdr, rxe, port_num and mask are initialized in ifc
 	 * layer
 	 */
 	pkt->opcode	= opcode;
 	pkt->qp		= qp;
 	pkt->psn	= qp->req.psn;
 	pkt->mask	= rxe_opcode[opcode].mask;
 	pkt->paylen	= paylen;
 	pkt->offset	= 0;
 	pkt->wqe	= wqe;

 	/* init skb */
 	av = rxe_get_av(pkt);
 	skb = rxe_init_packet(rxe, av, paylen, pkt);
 	if (unlikely(!skb))
 		return NULL;

 	/* init bth */
 	solicited = (ibwr->send_flags & IB_SEND_SOLICITED) &&
 			(pkt->mask & RXE_END_MASK) &&
 			((pkt->mask & (RXE_SEND_MASK)) ||
 			(pkt->mask & (RXE_WRITE_MASK | RXE_IMMDT_MASK)) ==
 			(RXE_WRITE_MASK | RXE_IMMDT_MASK));

 	pkey = (qp_type(qp) == IB_QPT_GSI) ?
 		 port->pkey_tbl[ibwr->wr.ud.pkey_index] :
 		 port->pkey_tbl[qp->attr.pkey_index];

 	qp_num = (pkt->mask & RXE_DETH_MASK) ? ibwr->wr.ud.remote_qpn :
 					 qp->attr.dest_qp_num;

 	ack_req = ((pkt->mask & RXE_END_MASK) ||
 		(qp->req.noack_pkts++ > RXE_MAX_PKT_PER_ACK));
 	if (ack_req)
 		qp->req.noack_pkts = 0;

 	bth_init(pkt, pkt->opcode, solicited, 0, pad, pkey, qp_num,
 		 ack_req, pkt->psn);

 	/* init optional headers */
 	if (pkt->mask & RXE_RETH_MASK) {
 		reth_set_rkey(pkt, ibwr->wr.rdma.rkey);
 		reth_set_va(pkt, wqe->iova);
 		reth_set_len(pkt, wqe->dma.length);
 	}

 	if (pkt->mask & RXE_IMMDT_MASK)
 		immdt_set_imm(pkt, ibwr->ex.imm_data);

 	if (pkt->mask & RXE_IETH_MASK)
 		ieth_set_rkey(pkt, ibwr->ex.invalidate_rkey);

 	if (pkt->mask & RXE_ATMETH_MASK) {
 		atmeth_set_va(pkt, wqe->iova);
 		if (opcode == IB_OPCODE_RC_COMPARE_SWAP ||
 		    opcode == IB_OPCODE_RD_COMPARE_SWAP) {
 			atmeth_set_swap_add(pkt, ibwr->wr.atomic.swap);
 			atmeth_set_comp(pkt, ibwr->wr.atomic.compare_add);
 		} else {
 			atmeth_set_swap_add(pkt, ibwr->wr.atomic.compare_add);
 		}
 		atmeth_set_rkey(pkt, ibwr->wr.atomic.rkey);
 	}

 	if (pkt->mask & RXE_DETH_MASK) {
 		if (qp->ibqp.qp_num == 1)
 			deth_set_qkey(pkt, GSI_QKEY);
 		else
 			deth_set_qkey(pkt, ibwr->wr.ud.remote_qkey);
 		deth_set_sqp(pkt, qp->ibqp.qp_num);
 	}

 	return skb;
 }

 static int fill_packet(struct rxe_qp *qp, struct rxe_send_wqe *wqe,
 		       struct rxe_pkt_info *pkt, struct sk_buff *skb,
 		       int paylen)
 {
 	struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
 	u32 crc = 0;
 	u32 *p;
 	int err;

 	err = rxe_prepare(rxe, pkt, skb, &crc);
 	if (err)
 		return err;

 	if (pkt->mask & RXE_WRITE_OR_SEND) {
 		if (wqe->wr.send_flags & IB_SEND_INLINE) {
 			u8 *tmp = &wqe->dma.inline_data[wqe->dma.sge_offset];

 			crc = rxe_crc32(rxe, crc, tmp, paylen);
 			memcpy(payload_addr(pkt), tmp, paylen);

 			wqe->dma.resid -= paylen;
 			wqe->dma.sge_offset += paylen;
 		} else {
 			err = copy_data(rxe, qp->pd, 0, &wqe->dma,
 					payload_addr(pkt), paylen,
 					from_mem_obj,
 					&crc);
 			if (err)
 				return err;
 		}
 	}
 	p = payload_addr(pkt) + paylen + bth_pad(pkt);

 	*p = ~crc;

 	return 0;
 }

 static void update_wqe_state(struct rxe_qp *qp,
 		struct rxe_send_wqe *wqe,
 		struct rxe_pkt_info *pkt)
 {
 	if (pkt->mask & RXE_END_MASK) {
 		if (qp_type(qp) == IB_QPT_RC)
 			wqe->state = wqe_state_pending;
 	} else {
 		wqe->state = wqe_state_processing;
 	}
 }

 static void update_wqe_psn(struct rxe_qp *qp,
 			   struct rxe_send_wqe *wqe,
 			   struct rxe_pkt_info *pkt,
 			   int payload)
 {
 	/* number of packets left to send including current one */
 	int num_pkt = (wqe->dma.resid + payload + qp->mtu - 1) / qp->mtu;

 	/* handle zero length packet case */
 	if (num_pkt == 0)
 		num_pkt = 1;

 	if (pkt->mask & RXE_START_MASK) {
 		wqe->first_psn = qp->req.psn;
 		wqe->last_psn = (qp->req.psn + num_pkt - 1) & BTH_PSN_MASK;
 	}

 	if (pkt->mask & RXE_READ_MASK)
 		qp->req.psn = (wqe->first_psn + num_pkt) & BTH_PSN_MASK;
 	else
 		qp->req.psn = (qp->req.psn + 1) & BTH_PSN_MASK;
 }

 static void save_state(struct rxe_send_wqe *wqe,
 		       struct rxe_qp *qp,
 		       struct rxe_send_wqe *rollback_wqe,
 		       u32 *rollback_psn)
 {
 	rollback_wqe->state     = wqe->state;
 	rollback_wqe->first_psn = wqe->first_psn;
 	rollback_wqe->last_psn  = wqe->last_psn;
 	*rollback_psn		= qp->req.psn;
 }

 static void rollback_state(struct rxe_send_wqe *wqe,
 			   struct rxe_qp *qp,
 			   struct rxe_send_wqe *rollback_wqe,
 			   u32 rollback_psn)
 {
 	wqe->state     = rollback_wqe->state;
 	wqe->first_psn = rollback_wqe->first_psn;
 	wqe->last_psn  = rollback_wqe->last_psn;
 	qp->req.psn    = rollback_psn;
 }

 static void update_state(struct rxe_qp *qp, struct rxe_send_wqe *wqe,
 			 struct rxe_pkt_info *pkt, int payload)
 {
 	qp->req.opcode = pkt->opcode;

 	if (pkt->mask & RXE_END_MASK)
 		qp->req.wqe_index = next_index(qp->sq.queue, qp->req.wqe_index);

 	qp->need_req_skb = 0;

 	if (qp->qp_timeout_jiffies && !timer_pending(&qp->retrans_timer))
 		mod_timer(&qp->retrans_timer,
 			  jiffies + qp->qp_timeout_jiffies);
 }

 int rxe_requester(void *arg)
 {
 	struct rxe_qp *qp = (struct rxe_qp *)arg;
 	struct rxe_pkt_info pkt;
 	struct sk_buff *skb;
 	struct rxe_send_wqe *wqe;
 	enum rxe_hdr_mask mask;
 	int payload;
 	int mtu;
 	int opcode;
 	int ret;
 	struct rxe_send_wqe rollback_wqe;
 	u32 rollback_psn;

 	rxe_add_ref(qp);

 next_wqe:
 	if (unlikely(!qp->valid || qp->req.state == QP_STATE_ERROR))
 		goto exit;

 	if (unlikely(qp->req.state == QP_STATE_RESET)) {
 		qp->req.wqe_index = consumer_index(qp->sq.queue);
 		qp->req.opcode = -1;
 		qp->req.need_rd_atomic = 0;
 		qp->req.wait_psn = 0;
 		qp->req.need_retry = 0;
 		goto exit;
 	}

 	if (unlikely(qp->req.need_retry)) {
 		req_retry(qp);
 		qp->req.need_retry = 0;
 	}

 	wqe = req_next_wqe(qp);
 	if (unlikely(!wqe))
 		goto exit;

 	if (wqe->mask & WR_REG_MASK) {
 		if (wqe->wr.opcode == IB_WR_LOCAL_INV) {
 			struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
 			struct rxe_mem *rmr;

 			rmr = rxe_pool_get_index(&rxe->mr_pool,
 						 wqe->wr.ex.invalidate_rkey >> 8);
 			if (!rmr) {
 				pr_err("No mr for key %#x\n",
 				       wqe->wr.ex.invalidate_rkey);
 				wqe->state = wqe_state_error;
 				wqe->status = IB_WC_MW_BIND_ERR;
 				goto exit;
 			}
 			rmr->state = RXE_MEM_STATE_FREE;
 			rxe_drop_ref(rmr);
 			wqe->state = wqe_state_done;
 			wqe->status = IB_WC_SUCCESS;
 		} else if (wqe->wr.opcode == IB_WR_REG_MR) {
 			struct rxe_mem *rmr = to_rmr(wqe->wr.wr.reg.mr);

 			rmr->state = RXE_MEM_STATE_VALID;
 			rmr->access = wqe->wr.wr.reg.access;
 			rmr->lkey = wqe->wr.wr.reg.key;
 			rmr->rkey = wqe->wr.wr.reg.key;
 			wqe->state = wqe_state_done;
 			wqe->status = IB_WC_SUCCESS;
 		} else {
 			goto exit;
 		}
 		qp->req.wqe_index = next_index(qp->sq.queue,
 						qp->req.wqe_index);
 		goto next_wqe;
 	}

 	if (unlikely(qp_type(qp) == IB_QPT_RC &&
 		     qp->req.psn > (qp->comp.psn + RXE_MAX_UNACKED_PSNS))) {
 		qp->req.wait_psn = 1;
 		goto exit;
 	}

 	/* Limit the number of inflight SKBs per QP */
 	if (unlikely(atomic_read(&qp->skb_out) >
 		     RXE_INFLIGHT_SKBS_PER_QP_HIGH)) {
 		qp->need_req_skb = 1;
 		goto exit;
 	}

 	opcode = next_opcode(qp, wqe, wqe->wr.opcode);
 	if (unlikely(opcode < 0)) {
 		wqe->status = IB_WC_LOC_QP_OP_ERR;
 		goto exit;
 	}

 	mask = rxe_opcode[opcode].mask;
 	if (unlikely(mask & RXE_READ_OR_ATOMIC)) {
 		if (check_init_depth(qp, wqe))
 			goto exit;
 	}

 	mtu = get_mtu(qp);
 	payload = (mask & RXE_WRITE_OR_SEND) ? wqe->dma.resid : 0;
 	if (payload > mtu) {
 		if (qp_type(qp) == IB_QPT_UD) {
 			/* C10-93.1.1: If the total sum of all the buffer lengths specified for a
 			 * UD message exceeds the MTU of the port as returned by QueryHCA, the CI
 			 * shall not emit any packets for this message. Further, the CI shall not
 			 * generate an error due to this condition.
 			 */

 			/* fake a successful UD send */
 			wqe->first_psn = qp->req.psn;
 			wqe->last_psn = qp->req.psn;
 			qp->req.psn = (qp->req.psn + 1) & BTH_PSN_MASK;
 			qp->req.opcode = IB_OPCODE_UD_SEND_ONLY;
 			qp->req.wqe_index = next_index(qp->sq.queue,
 						       qp->req.wqe_index);
 			wqe->state = wqe_state_done;
 			wqe->status = IB_WC_SUCCESS;
 			__rxe_do_task(&qp->comp.task);
 			rxe_drop_ref(qp);
 			return 0;
 		}
 		payload = mtu;
 	}

 	skb = init_req_packet(qp, wqe, opcode, payload, &pkt);
 	if (unlikely(!skb)) {
 		pr_err("qp#%d Failed allocating skb\n", qp_num(qp));
 		goto err;
 	}

 	if (fill_packet(qp, wqe, &pkt, skb, payload)) {
 		pr_debug("qp#%d Error during fill packet\n", qp_num(qp));
 		goto err;
 	}

 	/*
 	 * To prevent a race on wqe access between requester and completer,
 	 * wqe members state and psn need to be set before calling
 	 * rxe_xmit_packet().
 	 * Otherwise, completer might initiate an unjustified retry flow.
 	 */
 	save_state(wqe, qp, &rollback_wqe, &rollback_psn);
 	update_wqe_state(qp, wqe, &pkt);
 	update_wqe_psn(qp, wqe, &pkt, payload);
 	ret = rxe_xmit_packet(to_rdev(qp->ibqp.device), qp, &pkt, skb);
 	if (ret) {
 		qp->need_req_skb = 1;

 		rollback_state(wqe, qp, &rollback_wqe, rollback_psn);

 		if (ret == -EAGAIN) {
 			kfree_skb(skb);
 			rxe_run_task(&qp->req.task, 1);
 			goto exit;
 		}

 		goto err;
 	}

 	update_state(qp, wqe, &pkt, payload);

 	goto next_wqe;

 err:
 	kfree_skb(skb);
 	wqe->status = IB_WC_LOC_PROT_ERR;
 	wqe->state = wqe_state_error;
 	__rxe_do_task(&qp->comp.task);

 exit:
 	rxe_drop_ref(qp);
 	return -EAGAIN;
 }
	/*
	* Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
	* Copyright (c) 2015 System Fabric Works, 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/skbuff.h>
	#include <crypto/hash.h>

	#include "rxe.h"
	#include "rxe_loc.h"
	#include "rxe_queue.h"

	static int next_opcode(struct rxe_qp qp, struct rxe_send_wqe wqe,
	u32 opcode);

	static inline void retry_first_write_send(struct rxe_qp *qp,
	struct rxe_send_wqe *wqe,
	unsigned int mask, int npsn)
	{
	int i;

	for (i = 0; i < npsn; i++) {
	int to_send = (wqe->dma.resid > qp->mtu) ?
	qp->mtu : wqe->dma.resid;

	qp->req.opcode = next_opcode(qp, wqe,
	wqe->wr.opcode);

	if (wqe->wr.send_flags & IB_SEND_INLINE) {
	wqe->dma.resid -= to_send;
	wqe->dma.sge_offset += to_send;
	} else {
	advance_dma_data(&wqe->dma, to_send);
	}
	if (mask & WR_WRITE_MASK)
	wqe->iova += qp->mtu;
	}
	}

	static void req_retry(struct rxe_qp *qp)
	{
	struct rxe_send_wqe *wqe;
	unsigned int wqe_index;
	unsigned int mask;
	int npsn;
	int first = 1;

	wqe = queue_head(qp->sq.queue);
	npsn = (qp->comp.psn - wqe->first_psn) & BTH_PSN_MASK;

	qp->req.wqe_index = consumer_index(qp->sq.queue);
	qp->req.psn = qp->comp.psn;
	qp->req.opcode = -1;

	for (wqe_index = consumer_index(qp->sq.queue);
	wqe_index != producer_index(qp->sq.queue);
	wqe_index = next_index(qp->sq.queue, wqe_index)) {
	wqe = addr_from_index(qp->sq.queue, wqe_index);
	mask = wr_opcode_mask(wqe->wr.opcode, qp);

	if (wqe->state == wqe_state_posted)
	break;

	if (wqe->state == wqe_state_done)
	continue;

	wqe->iova = (mask & WR_ATOMIC_MASK) ?
	wqe->wr.wr.atomic.remote_addr :
	(mask & WR_READ_OR_WRITE_MASK) ?
	wqe->wr.wr.rdma.remote_addr :
	0;

	if (!first \|\| (mask & WR_READ_MASK) == 0) {
	wqe->dma.resid = wqe->dma.length;
	wqe->dma.cur_sge = 0;
	wqe->dma.sge_offset = 0;
	}

	if (first) {
	first = 0;

	if (mask & WR_WRITE_OR_SEND_MASK)
	retry_first_write_send(qp, wqe, mask, npsn);

	if (mask & WR_READ_MASK)
	wqe->iova += npsn * qp->mtu;
	}

	wqe->state = wqe_state_posted;
	}
	}

	void rnr_nak_timer(struct timer_list *t)
	{
	struct rxe_qp *qp = from_timer(qp, t, rnr_nak_timer);

	pr_debug("qp#%d rnr nak timer fired\n", qp_num(qp));
	rxe_run_task(&qp->req.task, 1);
	}

	static struct rxe_send_wqe req_next_wqe(struct rxe_qp qp)
	{
	struct rxe_send_wqe *wqe = queue_head(qp->sq.queue);
	unsigned long flags;

	if (unlikely(qp->req.state == QP_STATE_DRAIN)) {
	/* check to see if we are drained;
	* state_lock used by requester and completer
	*/
	spin_lock_irqsave(&qp->state_lock, flags);
	do {
	if (qp->req.state != QP_STATE_DRAIN) {
	/* comp just finished */
	spin_unlock_irqrestore(&qp->state_lock,
	flags);
	break;
	}

	if (wqe && ((qp->req.wqe_index !=
	consumer_index(qp->sq.queue)) \|\|
	(wqe->state != wqe_state_posted))) {
	/* comp not done yet */
	spin_unlock_irqrestore(&qp->state_lock,
	flags);
	break;
	}

	qp->req.state = QP_STATE_DRAINED;
	spin_unlock_irqrestore(&qp->state_lock, flags);

	if (qp->ibqp.event_handler) {
	struct ib_event ev;

	ev.device = qp->ibqp.device;
	ev.element.qp = &qp->ibqp;
	ev.event = IB_EVENT_SQ_DRAINED;
	qp->ibqp.event_handler(&ev,
	qp->ibqp.qp_context);
	}
	} while (0);
	}

	if (qp->req.wqe_index == producer_index(qp->sq.queue))
	return NULL;

	wqe = addr_from_index(qp->sq.queue, qp->req.wqe_index);

	if (unlikely((qp->req.state == QP_STATE_DRAIN \|\|
	qp->req.state == QP_STATE_DRAINED) &&
	(wqe->state != wqe_state_processing)))
	return NULL;

	if (unlikely((wqe->wr.send_flags & IB_SEND_FENCE) &&
	(qp->req.wqe_index != consumer_index(qp->sq.queue)))) {
	qp->req.wait_fence = 1;
	return NULL;
	}

	wqe->mask = wr_opcode_mask(wqe->wr.opcode, qp);
	return wqe;
	}

	static int next_opcode_rc(struct rxe_qp *qp, u32 opcode, int fits)
	{
	switch (opcode) {
	case IB_WR_RDMA_WRITE:
	if (qp->req.opcode == IB_OPCODE_RC_RDMA_WRITE_FIRST \|\|
	qp->req.opcode == IB_OPCODE_RC_RDMA_WRITE_MIDDLE)
	return fits ?
	IB_OPCODE_RC_RDMA_WRITE_LAST :
	IB_OPCODE_RC_RDMA_WRITE_MIDDLE;
	else
	return fits ?
	IB_OPCODE_RC_RDMA_WRITE_ONLY :
	IB_OPCODE_RC_RDMA_WRITE_FIRST;

	case IB_WR_RDMA_WRITE_WITH_IMM:
	if (qp->req.opcode == IB_OPCODE_RC_RDMA_WRITE_FIRST \|\|
	qp->req.opcode == IB_OPCODE_RC_RDMA_WRITE_MIDDLE)
	return fits ?
	IB_OPCODE_RC_RDMA_WRITE_LAST_WITH_IMMEDIATE :
	IB_OPCODE_RC_RDMA_WRITE_MIDDLE;
	else
	return fits ?
	IB_OPCODE_RC_RDMA_WRITE_ONLY_WITH_IMMEDIATE :
	IB_OPCODE_RC_RDMA_WRITE_FIRST;

	case IB_WR_SEND:
	if (qp->req.opcode == IB_OPCODE_RC_SEND_FIRST \|\|
	qp->req.opcode == IB_OPCODE_RC_SEND_MIDDLE)
	return fits ?
	IB_OPCODE_RC_SEND_LAST :
	IB_OPCODE_RC_SEND_MIDDLE;
	else
	return fits ?
	IB_OPCODE_RC_SEND_ONLY :
	IB_OPCODE_RC_SEND_FIRST;

	case IB_WR_SEND_WITH_IMM:
	if (qp->req.opcode == IB_OPCODE_RC_SEND_FIRST \|\|
	qp->req.opcode == IB_OPCODE_RC_SEND_MIDDLE)
	return fits ?
	IB_OPCODE_RC_SEND_LAST_WITH_IMMEDIATE :
	IB_OPCODE_RC_SEND_MIDDLE;
	else
	return fits ?
	IB_OPCODE_RC_SEND_ONLY_WITH_IMMEDIATE :
	IB_OPCODE_RC_SEND_FIRST;

	case IB_WR_RDMA_READ:
	return IB_OPCODE_RC_RDMA_READ_REQUEST;

	case IB_WR_ATOMIC_CMP_AND_SWP:
	return IB_OPCODE_RC_COMPARE_SWAP;

	case IB_WR_ATOMIC_FETCH_AND_ADD:
	return IB_OPCODE_RC_FETCH_ADD;

	case IB_WR_SEND_WITH_INV:
	if (qp->req.opcode == IB_OPCODE_RC_SEND_FIRST \|\|
	qp->req.opcode == IB_OPCODE_RC_SEND_MIDDLE)
	return fits ? IB_OPCODE_RC_SEND_LAST_WITH_INVALIDATE :
	IB_OPCODE_RC_SEND_MIDDLE;
	else
	return fits ? IB_OPCODE_RC_SEND_ONLY_WITH_INVALIDATE :
	IB_OPCODE_RC_SEND_FIRST;
	case IB_WR_REG_MR:
	case IB_WR_LOCAL_INV:
	return opcode;
	}

	return -EINVAL;
	}

	static int next_opcode_uc(struct rxe_qp *qp, u32 opcode, int fits)
	{
	switch (opcode) {
	case IB_WR_RDMA_WRITE:
	if (qp->req.opcode == IB_OPCODE_UC_RDMA_WRITE_FIRST \|\|
	qp->req.opcode == IB_OPCODE_UC_RDMA_WRITE_MIDDLE)
	return fits ?
	IB_OPCODE_UC_RDMA_WRITE_LAST :
	IB_OPCODE_UC_RDMA_WRITE_MIDDLE;
	else
	return fits ?
	IB_OPCODE_UC_RDMA_WRITE_ONLY :
	IB_OPCODE_UC_RDMA_WRITE_FIRST;

	case IB_WR_RDMA_WRITE_WITH_IMM:
	if (qp->req.opcode == IB_OPCODE_UC_RDMA_WRITE_FIRST \|\|
	qp->req.opcode == IB_OPCODE_UC_RDMA_WRITE_MIDDLE)
	return fits ?
	IB_OPCODE_UC_RDMA_WRITE_LAST_WITH_IMMEDIATE :
	IB_OPCODE_UC_RDMA_WRITE_MIDDLE;
	else
	return fits ?
	IB_OPCODE_UC_RDMA_WRITE_ONLY_WITH_IMMEDIATE :
	IB_OPCODE_UC_RDMA_WRITE_FIRST;

	case IB_WR_SEND:
	if (qp->req.opcode == IB_OPCODE_UC_SEND_FIRST \|\|
	qp->req.opcode == IB_OPCODE_UC_SEND_MIDDLE)
	return fits ?
	IB_OPCODE_UC_SEND_LAST :
	IB_OPCODE_UC_SEND_MIDDLE;
	else
	return fits ?
	IB_OPCODE_UC_SEND_ONLY :
	IB_OPCODE_UC_SEND_FIRST;

	case IB_WR_SEND_WITH_IMM:
	if (qp->req.opcode == IB_OPCODE_UC_SEND_FIRST \|\|
	qp->req.opcode == IB_OPCODE_UC_SEND_MIDDLE)
	return fits ?
	IB_OPCODE_UC_SEND_LAST_WITH_IMMEDIATE :
	IB_OPCODE_UC_SEND_MIDDLE;
	else
	return fits ?
	IB_OPCODE_UC_SEND_ONLY_WITH_IMMEDIATE :
	IB_OPCODE_UC_SEND_FIRST;
	}

	return -EINVAL;
	}

	static int next_opcode(struct rxe_qp qp, struct rxe_send_wqe wqe,
	u32 opcode)
	{
	int fits = (wqe->dma.resid <= qp->mtu);

	switch (qp_type(qp)) {
	case IB_QPT_RC:
	return next_opcode_rc(qp, opcode, fits);

	case IB_QPT_UC:
	return next_opcode_uc(qp, opcode, fits);

	case IB_QPT_SMI:
	case IB_QPT_UD:
	case IB_QPT_GSI:
	switch (opcode) {
	case IB_WR_SEND:
	return IB_OPCODE_UD_SEND_ONLY;

	case IB_WR_SEND_WITH_IMM:
	return IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE;
	}
	break;

	default:
	break;
	}

	return -EINVAL;
	}

	static inline int check_init_depth(struct rxe_qp qp, struct rxe_send_wqe wqe)
	{
	int depth;

	if (wqe->has_rd_atomic)
	return 0;

	qp->req.need_rd_atomic = 1;
	depth = atomic_dec_return(&qp->req.rd_atomic);

	if (depth >= 0) {
	qp->req.need_rd_atomic = 0;
	wqe->has_rd_atomic = 1;
	return 0;
	}

	atomic_inc(&qp->req.rd_atomic);
	return -EAGAIN;
	}

	static inline int get_mtu(struct rxe_qp *qp)
	{
	struct rxe_dev *rxe = to_rdev(qp->ibqp.device);

	if ((qp_type(qp) == IB_QPT_RC) \|\| (qp_type(qp) == IB_QPT_UC))
	return qp->mtu;

	return rxe->port.mtu_cap;
	}

	static struct sk_buff init_req_packet(struct rxe_qp qp,
	struct rxe_send_wqe *wqe,
	int opcode, int payload,
	struct rxe_pkt_info *pkt)
	{
	struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
	struct rxe_port *port = &rxe->port;
	struct sk_buff *skb;
	struct rxe_send_wr *ibwr = &wqe->wr;
	struct rxe_av *av;
	int pad = (-payload) & 0x3;
	int paylen;
	int solicited;
	u16 pkey;
	u32 qp_num;
	int ack_req;

	/* length from start of bth to end of icrc */
	paylen = rxe_opcode[opcode].length + payload + pad + RXE_ICRC_SIZE;

	/* pkt->hdr, rxe, port_num and mask are initialized in ifc
	* layer
	*/
	pkt->opcode = opcode;
	pkt->qp = qp;
	pkt->psn = qp->req.psn;
	pkt->mask = rxe_opcode[opcode].mask;
	pkt->paylen = paylen;
	pkt->offset = 0;
	pkt->wqe = wqe;

	/* init skb */
	av = rxe_get_av(pkt);
	skb = rxe_init_packet(rxe, av, paylen, pkt);
	if (unlikely(!skb))
	return NULL;

	/* init bth */
	solicited = (ibwr->send_flags & IB_SEND_SOLICITED) &&
	(pkt->mask & RXE_END_MASK) &&
	((pkt->mask & (RXE_SEND_MASK)) \|\|
	(pkt->mask & (RXE_WRITE_MASK \| RXE_IMMDT_MASK)) ==
	(RXE_WRITE_MASK \| RXE_IMMDT_MASK));

	pkey = (qp_type(qp) == IB_QPT_GSI) ?
	port->pkey_tbl[ibwr->wr.ud.pkey_index] :
	port->pkey_tbl[qp->attr.pkey_index];

	qp_num = (pkt->mask & RXE_DETH_MASK) ? ibwr->wr.ud.remote_qpn :
	qp->attr.dest_qp_num;

	ack_req = ((pkt->mask & RXE_END_MASK) \|\|
	(qp->req.noack_pkts++ > RXE_MAX_PKT_PER_ACK));
	if (ack_req)
	qp->req.noack_pkts = 0;

	bth_init(pkt, pkt->opcode, solicited, 0, pad, pkey, qp_num,
	ack_req, pkt->psn);

	/* init optional headers */
	if (pkt->mask & RXE_RETH_MASK) {
	reth_set_rkey(pkt, ibwr->wr.rdma.rkey);
	reth_set_va(pkt, wqe->iova);
	reth_set_len(pkt, wqe->dma.length);
	}

	if (pkt->mask & RXE_IMMDT_MASK)
	immdt_set_imm(pkt, ibwr->ex.imm_data);

	if (pkt->mask & RXE_IETH_MASK)
	ieth_set_rkey(pkt, ibwr->ex.invalidate_rkey);

	if (pkt->mask & RXE_ATMETH_MASK) {
	atmeth_set_va(pkt, wqe->iova);
	if (opcode == IB_OPCODE_RC_COMPARE_SWAP \|\|
	opcode == IB_OPCODE_RD_COMPARE_SWAP) {
	atmeth_set_swap_add(pkt, ibwr->wr.atomic.swap);
	atmeth_set_comp(pkt, ibwr->wr.atomic.compare_add);
	} else {
	atmeth_set_swap_add(pkt, ibwr->wr.atomic.compare_add);
	}
	atmeth_set_rkey(pkt, ibwr->wr.atomic.rkey);
	}

	if (pkt->mask & RXE_DETH_MASK) {
	if (qp->ibqp.qp_num == 1)
	deth_set_qkey(pkt, GSI_QKEY);
	else
	deth_set_qkey(pkt, ibwr->wr.ud.remote_qkey);
	deth_set_sqp(pkt, qp->ibqp.qp_num);
	}

	return skb;
	}

	static int fill_packet(struct rxe_qp qp, struct rxe_send_wqe wqe,
	struct rxe_pkt_info pkt, struct sk_buff skb,
	int paylen)
	{
	struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
	u32 crc = 0;
	u32 *p;
	int err;

	err = rxe_prepare(rxe, pkt, skb, &crc);
	if (err)
	return err;

	if (pkt->mask & RXE_WRITE_OR_SEND) {
	if (wqe->wr.send_flags & IB_SEND_INLINE) {
	u8 *tmp = &wqe->dma.inline_data[wqe->dma.sge_offset];

	crc = rxe_crc32(rxe, crc, tmp, paylen);
	memcpy(payload_addr(pkt), tmp, paylen);

	wqe->dma.resid -= paylen;
	wqe->dma.sge_offset += paylen;
	} else {
	err = copy_data(rxe, qp->pd, 0, &wqe->dma,
	payload_addr(pkt), paylen,
	from_mem_obj,
	&crc);
	if (err)
	return err;
	}
	}
	p = payload_addr(pkt) + paylen + bth_pad(pkt);

	*p = ~crc;

	return 0;
	}

	static void update_wqe_state(struct rxe_qp *qp,
	struct rxe_send_wqe *wqe,
	struct rxe_pkt_info *pkt)
	{
	if (pkt->mask & RXE_END_MASK) {
	if (qp_type(qp) == IB_QPT_RC)
	wqe->state = wqe_state_pending;
	} else {
	wqe->state = wqe_state_processing;
	}
	}

	static void update_wqe_psn(struct rxe_qp *qp,
	struct rxe_send_wqe *wqe,
	struct rxe_pkt_info *pkt,
	int payload)
	{
	/* number of packets left to send including current one */
	int num_pkt = (wqe->dma.resid + payload + qp->mtu - 1) / qp->mtu;

	/* handle zero length packet case */
	if (num_pkt == 0)
	num_pkt = 1;

	if (pkt->mask & RXE_START_MASK) {
	wqe->first_psn = qp->req.psn;
	wqe->last_psn = (qp->req.psn + num_pkt - 1) & BTH_PSN_MASK;
	}

	if (pkt->mask & RXE_READ_MASK)
	qp->req.psn = (wqe->first_psn + num_pkt) & BTH_PSN_MASK;
	else
	qp->req.psn = (qp->req.psn + 1) & BTH_PSN_MASK;
	}

	static void save_state(struct rxe_send_wqe *wqe,
	struct rxe_qp *qp,
	struct rxe_send_wqe *rollback_wqe,
	u32 *rollback_psn)
	{
	rollback_wqe->state = wqe->state;
	rollback_wqe->first_psn = wqe->first_psn;
	rollback_wqe->last_psn = wqe->last_psn;
	*rollback_psn = qp->req.psn;
	}

	static void rollback_state(struct rxe_send_wqe *wqe,
	struct rxe_qp *qp,
	struct rxe_send_wqe *rollback_wqe,
	u32 rollback_psn)
	{
	wqe->state = rollback_wqe->state;
	wqe->first_psn = rollback_wqe->first_psn;
	wqe->last_psn = rollback_wqe->last_psn;
	qp->req.psn = rollback_psn;
	}

	static void update_state(struct rxe_qp qp, struct rxe_send_wqe wqe,
	struct rxe_pkt_info *pkt, int payload)
	{
	qp->req.opcode = pkt->opcode;

	if (pkt->mask & RXE_END_MASK)
	qp->req.wqe_index = next_index(qp->sq.queue, qp->req.wqe_index);

	qp->need_req_skb = 0;

	if (qp->qp_timeout_jiffies && !timer_pending(&qp->retrans_timer))
	mod_timer(&qp->retrans_timer,
	jiffies + qp->qp_timeout_jiffies);
	}

	int rxe_requester(void *arg)
	{
	struct rxe_qp qp = (struct rxe_qp )arg;
	struct rxe_pkt_info pkt;
	struct sk_buff *skb;
	struct rxe_send_wqe *wqe;
	enum rxe_hdr_mask mask;
	int payload;
	int mtu;
	int opcode;
	int ret;
	struct rxe_send_wqe rollback_wqe;
	u32 rollback_psn;

	rxe_add_ref(qp);

	next_wqe:
	if (unlikely(!qp->valid \|\| qp->req.state == QP_STATE_ERROR))
	goto exit;

	if (unlikely(qp->req.state == QP_STATE_RESET)) {
	qp->req.wqe_index = consumer_index(qp->sq.queue);
	qp->req.opcode = -1;
	qp->req.need_rd_atomic = 0;
	qp->req.wait_psn = 0;
	qp->req.need_retry = 0;
	goto exit;
	}

	if (unlikely(qp->req.need_retry)) {
	req_retry(qp);
	qp->req.need_retry = 0;
	}

	wqe = req_next_wqe(qp);
	if (unlikely(!wqe))
	goto exit;

	if (wqe->mask & WR_REG_MASK) {
	if (wqe->wr.opcode == IB_WR_LOCAL_INV) {
	struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
	struct rxe_mem *rmr;

	rmr = rxe_pool_get_index(&rxe->mr_pool,
	wqe->wr.ex.invalidate_rkey >> 8);
	if (!rmr) {
	pr_err("No mr for key %#x\n",
	wqe->wr.ex.invalidate_rkey);
	wqe->state = wqe_state_error;
	wqe->status = IB_WC_MW_BIND_ERR;
	goto exit;
	}
	rmr->state = RXE_MEM_STATE_FREE;
	rxe_drop_ref(rmr);
	wqe->state = wqe_state_done;
	wqe->status = IB_WC_SUCCESS;
	} else if (wqe->wr.opcode == IB_WR_REG_MR) {
	struct rxe_mem *rmr = to_rmr(wqe->wr.wr.reg.mr);

	rmr->state = RXE_MEM_STATE_VALID;
	rmr->access = wqe->wr.wr.reg.access;
	rmr->lkey = wqe->wr.wr.reg.key;
	rmr->rkey = wqe->wr.wr.reg.key;
	wqe->state = wqe_state_done;
	wqe->status = IB_WC_SUCCESS;
	} else {
	goto exit;
	}
	qp->req.wqe_index = next_index(qp->sq.queue,
	qp->req.wqe_index);
	goto next_wqe;
	}

	if (unlikely(qp_type(qp) == IB_QPT_RC &&
	qp->req.psn > (qp->comp.psn + RXE_MAX_UNACKED_PSNS))) {
	qp->req.wait_psn = 1;
	goto exit;
	}

	/* Limit the number of inflight SKBs per QP */
	if (unlikely(atomic_read(&qp->skb_out) >
	RXE_INFLIGHT_SKBS_PER_QP_HIGH)) {
	qp->need_req_skb = 1;
	goto exit;
	}

	opcode = next_opcode(qp, wqe, wqe->wr.opcode);
	if (unlikely(opcode < 0)) {
	wqe->status = IB_WC_LOC_QP_OP_ERR;
	goto exit;
	}

	mask = rxe_opcode[opcode].mask;
	if (unlikely(mask & RXE_READ_OR_ATOMIC)) {
	if (check_init_depth(qp, wqe))
	goto exit;
	}

	mtu = get_mtu(qp);
	payload = (mask & RXE_WRITE_OR_SEND) ? wqe->dma.resid : 0;
	if (payload > mtu) {
	if (qp_type(qp) == IB_QPT_UD) {
	/* C10-93.1.1: If the total sum of all the buffer lengths specified for a
	* UD message exceeds the MTU of the port as returned by QueryHCA, the CI
	* shall not emit any packets for this message. Further, the CI shall not
	* generate an error due to this condition.
	*/

	/* fake a successful UD send */
	wqe->first_psn = qp->req.psn;
	wqe->last_psn = qp->req.psn;
	qp->req.psn = (qp->req.psn + 1) & BTH_PSN_MASK;
	qp->req.opcode = IB_OPCODE_UD_SEND_ONLY;
	qp->req.wqe_index = next_index(qp->sq.queue,
	qp->req.wqe_index);
	wqe->state = wqe_state_done;
	wqe->status = IB_WC_SUCCESS;
	__rxe_do_task(&qp->comp.task);
	rxe_drop_ref(qp);
	return 0;
	}
	payload = mtu;
	}

	skb = init_req_packet(qp, wqe, opcode, payload, &pkt);
	if (unlikely(!skb)) {
	pr_err("qp#%d Failed allocating skb\n", qp_num(qp));
	goto err;
	}

	if (fill_packet(qp, wqe, &pkt, skb, payload)) {
	pr_debug("qp#%d Error during fill packet\n", qp_num(qp));
	goto err;
	}

	/*
	* To prevent a race on wqe access between requester and completer,
	* wqe members state and psn need to be set before calling
	* rxe_xmit_packet().
	* Otherwise, completer might initiate an unjustified retry flow.
	*/
	save_state(wqe, qp, &rollback_wqe, &rollback_psn);
	update_wqe_state(qp, wqe, &pkt);
	update_wqe_psn(qp, wqe, &pkt, payload);
	ret = rxe_xmit_packet(to_rdev(qp->ibqp.device), qp, &pkt, skb);
	if (ret) {
	qp->need_req_skb = 1;

	rollback_state(wqe, qp, &rollback_wqe, rollback_psn);

	if (ret == -EAGAIN) {
	kfree_skb(skb);
	rxe_run_task(&qp->req.task, 1);
	goto exit;
	}

	goto err;
	}

	update_state(qp, wqe, &pkt, payload);

	goto next_wqe;

	err:
	kfree_skb(skb);
	wqe->status = IB_WC_LOC_PROT_ERR;
	wqe->state = wqe_state_error;
	__rxe_do_task(&qp->comp.task);

	exit:
	rxe_drop_ref(qp);
	return -EAGAIN;
	}