drivers/infiniband/ulp/iser/iser_memory.c - linux - Git at Google

 /*
  * Copyright (c) 2004, 2005, 2006 Voltaire, Inc. All rights reserved.
  * Copyright (c) 2013-2014 Mellanox Technologies. 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/module.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/mm.h>
 #include <linux/highmem.h>
 #include <linux/scatterlist.h>

 #include "iscsi_iser.h"

 void iser_reg_comp(struct ib_cq *cq, struct ib_wc *wc)
 {
 	iser_err_comp(wc, "memreg");
 }

 static struct iser_fr_desc *
 iser_reg_desc_get_fr(struct ib_conn *ib_conn)
 {
 	struct iser_fr_pool *fr_pool = &ib_conn->fr_pool;
 	struct iser_fr_desc *desc;
 	unsigned long flags;

 	spin_lock_irqsave(&fr_pool->lock, flags);
 	desc = list_first_entry(&fr_pool->list,
 				struct iser_fr_desc, list);
 	list_del(&desc->list);
 	spin_unlock_irqrestore(&fr_pool->lock, flags);

 	return desc;
 }

 static void
 iser_reg_desc_put_fr(struct ib_conn *ib_conn,
 		     struct iser_fr_desc *desc)
 {
 	struct iser_fr_pool *fr_pool = &ib_conn->fr_pool;
 	unsigned long flags;

 	spin_lock_irqsave(&fr_pool->lock, flags);
 	list_add(&desc->list, &fr_pool->list);
 	spin_unlock_irqrestore(&fr_pool->lock, flags);
 }

 int iser_dma_map_task_data(struct iscsi_iser_task *iser_task,
 			    struct iser_data_buf *data,
 			    enum iser_data_dir iser_dir,
 			    enum dma_data_direction dma_dir)
 {
 	struct ib_device *dev;

 	iser_task->dir[iser_dir] = 1;
 	dev = iser_task->iser_conn->ib_conn.device->ib_device;

 	data->dma_nents = ib_dma_map_sg(dev, data->sg, data->size, dma_dir);
 	if (unlikely(data->dma_nents == 0)) {
 		iser_err("dma_map_sg failed!!!\n");
 		return -EINVAL;
 	}
 	return 0;
 }

 void iser_dma_unmap_task_data(struct iscsi_iser_task *iser_task,
 			      struct iser_data_buf *data,
 			      enum dma_data_direction dir)
 {
 	struct ib_device *dev;

 	dev = iser_task->iser_conn->ib_conn.device->ib_device;
 	ib_dma_unmap_sg(dev, data->sg, data->size, dir);
 }

 static int
 iser_reg_dma(struct iser_device *device, struct iser_data_buf *mem,
 	     struct iser_mem_reg *reg)
 {
 	struct scatterlist *sg = mem->sg;

 	reg->sge.lkey = device->pd->local_dma_lkey;
 	/*
 	 * FIXME: rework the registration code path to differentiate
 	 * rkey/lkey use cases
 	 */

 	if (device->pd->flags & IB_PD_UNSAFE_GLOBAL_RKEY)
 		reg->rkey = device->pd->unsafe_global_rkey;
 	else
 		reg->rkey = 0;
 	reg->sge.addr = sg_dma_address(&sg[0]);
 	reg->sge.length = sg_dma_len(&sg[0]);

 	iser_dbg("Single DMA entry: lkey=0x%x, rkey=0x%x, addr=0x%llx,"
 		 " length=0x%x\n", reg->sge.lkey, reg->rkey,
 		 reg->sge.addr, reg->sge.length);

 	return 0;
 }

 void iser_unreg_mem_fastreg(struct iscsi_iser_task *iser_task,
 			    enum iser_data_dir cmd_dir)
 {
 	struct iser_mem_reg *reg = &iser_task->rdma_reg[cmd_dir];
 	struct iser_fr_desc *desc;
 	struct ib_mr_status mr_status;

 	desc = reg->mem_h;
 	if (!desc)
 		return;

 	/*
 	 * The signature MR cannot be invalidated and reused without checking.
 	 * libiscsi calls the check_protection transport handler only if
 	 * SCSI-Response is received. And the signature MR is not checked if
 	 * the task is completed for some other reason like a timeout or error
 	 * handling. That's why we must check the signature MR here before
 	 * putting it to the free pool.
 	 */
 	if (unlikely(desc->sig_protected)) {
 		desc->sig_protected = false;
 		ib_check_mr_status(desc->rsc.sig_mr, IB_MR_CHECK_SIG_STATUS,
 				   &mr_status);
 	}
 	iser_reg_desc_put_fr(&iser_task->iser_conn->ib_conn, reg->mem_h);
 	reg->mem_h = NULL;
 }

 static void
 iser_set_dif_domain(struct scsi_cmnd *sc, struct ib_sig_domain *domain)
 {
 	domain->sig_type = IB_SIG_TYPE_T10_DIF;
 	domain->sig.dif.pi_interval = scsi_prot_interval(sc);
 	domain->sig.dif.ref_tag = t10_pi_ref_tag(sc->request);
 	/*
 	 * At the moment we hard code those, but in the future
 	 * we will take them from sc.
 	 */
 	domain->sig.dif.apptag_check_mask = 0xffff;
 	domain->sig.dif.app_escape = true;
 	domain->sig.dif.ref_escape = true;
 	if (sc->prot_flags & SCSI_PROT_REF_INCREMENT)
 		domain->sig.dif.ref_remap = true;
 };

 static int
 iser_set_sig_attrs(struct scsi_cmnd *sc, struct ib_sig_attrs *sig_attrs)
 {
 	switch (scsi_get_prot_op(sc)) {
 	case SCSI_PROT_WRITE_INSERT:
 	case SCSI_PROT_READ_STRIP:
 		sig_attrs->mem.sig_type = IB_SIG_TYPE_NONE;
 		iser_set_dif_domain(sc, &sig_attrs->wire);
 		sig_attrs->wire.sig.dif.bg_type = IB_T10DIF_CRC;
 		break;
 	case SCSI_PROT_READ_INSERT:
 	case SCSI_PROT_WRITE_STRIP:
 		sig_attrs->wire.sig_type = IB_SIG_TYPE_NONE;
 		iser_set_dif_domain(sc, &sig_attrs->mem);
 		sig_attrs->mem.sig.dif.bg_type = sc->prot_flags & SCSI_PROT_IP_CHECKSUM ?
 						IB_T10DIF_CSUM : IB_T10DIF_CRC;
 		break;
 	case SCSI_PROT_READ_PASS:
 	case SCSI_PROT_WRITE_PASS:
 		iser_set_dif_domain(sc, &sig_attrs->wire);
 		sig_attrs->wire.sig.dif.bg_type = IB_T10DIF_CRC;
 		iser_set_dif_domain(sc, &sig_attrs->mem);
 		sig_attrs->mem.sig.dif.bg_type = sc->prot_flags & SCSI_PROT_IP_CHECKSUM ?
 						IB_T10DIF_CSUM : IB_T10DIF_CRC;
 		break;
 	default:
 		iser_err("Unsupported PI operation %d\n",
 			 scsi_get_prot_op(sc));
 		return -EINVAL;
 	}

 	return 0;
 }

 static inline void
 iser_set_prot_checks(struct scsi_cmnd *sc, u8 *mask)
 {
 	*mask = 0;
 	if (sc->prot_flags & SCSI_PROT_REF_CHECK)
 		*mask |= IB_SIG_CHECK_REFTAG;
 	if (sc->prot_flags & SCSI_PROT_GUARD_CHECK)
 		*mask |= IB_SIG_CHECK_GUARD;
 }

 static inline void
 iser_inv_rkey(struct ib_send_wr *inv_wr,
 	      struct ib_mr *mr,
 	      struct ib_cqe *cqe,
 	      struct ib_send_wr *next_wr)
 {
 	inv_wr->opcode = IB_WR_LOCAL_INV;
 	inv_wr->wr_cqe = cqe;
 	inv_wr->ex.invalidate_rkey = mr->rkey;
 	inv_wr->send_flags = 0;
 	inv_wr->num_sge = 0;
 	inv_wr->next = next_wr;
 }

 static int
 iser_reg_sig_mr(struct iscsi_iser_task *iser_task,
 		struct iser_data_buf *mem,
 		struct iser_data_buf *sig_mem,
 		struct iser_reg_resources *rsc,
 		struct iser_mem_reg *sig_reg)
 {
 	struct iser_tx_desc *tx_desc = &iser_task->desc;
 	struct ib_cqe *cqe = &iser_task->iser_conn->ib_conn.reg_cqe;
 	struct ib_mr *mr = rsc->sig_mr;
 	struct ib_sig_attrs *sig_attrs = mr->sig_attrs;
 	struct ib_reg_wr *wr = &tx_desc->reg_wr;
 	int ret;

 	memset(sig_attrs, 0, sizeof(*sig_attrs));
 	ret = iser_set_sig_attrs(iser_task->sc, sig_attrs);
 	if (ret)
 		goto err;

 	iser_set_prot_checks(iser_task->sc, &sig_attrs->check_mask);

 	if (rsc->mr_valid)
 		iser_inv_rkey(&tx_desc->inv_wr, mr, cqe, &wr->wr);

 	ib_update_fast_reg_key(mr, ib_inc_rkey(mr->rkey));

 	ret = ib_map_mr_sg_pi(mr, mem->sg, mem->dma_nents, NULL,
 			      sig_mem->sg, sig_mem->dma_nents, NULL, SZ_4K);
 	if (unlikely(ret)) {
 		iser_err("failed to map PI sg (%d)\n",
 			 mem->dma_nents + sig_mem->dma_nents);
 		goto err;
 	}

 	memset(wr, 0, sizeof(*wr));
 	wr->wr.next = &tx_desc->send_wr;
 	wr->wr.opcode = IB_WR_REG_MR_INTEGRITY;
 	wr->wr.wr_cqe = cqe;
 	wr->wr.num_sge = 0;
 	wr->wr.send_flags = 0;
 	wr->mr = mr;
 	wr->key = mr->rkey;
 	wr->access = IB_ACCESS_LOCAL_WRITE |
 		     IB_ACCESS_REMOTE_READ |
 		     IB_ACCESS_REMOTE_WRITE;
 	rsc->mr_valid = 1;

 	sig_reg->sge.lkey = mr->lkey;
 	sig_reg->rkey = mr->rkey;
 	sig_reg->sge.addr = mr->iova;
 	sig_reg->sge.length = mr->length;

 	iser_dbg("lkey=0x%x rkey=0x%x addr=0x%llx length=%u\n",
 		 sig_reg->sge.lkey, sig_reg->rkey, sig_reg->sge.addr,
 		 sig_reg->sge.length);
 err:
 	return ret;
 }

 static int iser_fast_reg_mr(struct iscsi_iser_task *iser_task,
 			    struct iser_data_buf *mem,
 			    struct iser_reg_resources *rsc,
 			    struct iser_mem_reg *reg)
 {
 	struct iser_tx_desc *tx_desc = &iser_task->desc;
 	struct ib_cqe *cqe = &iser_task->iser_conn->ib_conn.reg_cqe;
 	struct ib_mr *mr = rsc->mr;
 	struct ib_reg_wr *wr = &tx_desc->reg_wr;
 	int n;

 	if (rsc->mr_valid)
 		iser_inv_rkey(&tx_desc->inv_wr, mr, cqe, &wr->wr);

 	ib_update_fast_reg_key(mr, ib_inc_rkey(mr->rkey));

 	n = ib_map_mr_sg(mr, mem->sg, mem->dma_nents, NULL, SZ_4K);
 	if (unlikely(n != mem->dma_nents)) {
 		iser_err("failed to map sg (%d/%d)\n",
 			 n, mem->dma_nents);
 		return n < 0 ? n : -EINVAL;
 	}

 	wr->wr.next = &tx_desc->send_wr;
 	wr->wr.opcode = IB_WR_REG_MR;
 	wr->wr.wr_cqe = cqe;
 	wr->wr.send_flags = 0;
 	wr->wr.num_sge = 0;
 	wr->mr = mr;
 	wr->key = mr->rkey;
 	wr->access = IB_ACCESS_LOCAL_WRITE  |
 		     IB_ACCESS_REMOTE_WRITE |
 		     IB_ACCESS_REMOTE_READ;

 	rsc->mr_valid = 1;

 	reg->sge.lkey = mr->lkey;
 	reg->rkey = mr->rkey;
 	reg->sge.addr = mr->iova;
 	reg->sge.length = mr->length;

 	iser_dbg("lkey=0x%x rkey=0x%x addr=0x%llx length=0x%x\n",
 		 reg->sge.lkey, reg->rkey, reg->sge.addr, reg->sge.length);

 	return 0;
 }

 static int
 iser_reg_data_sg(struct iscsi_iser_task *task,
 		 struct iser_data_buf *mem,
 		 struct iser_fr_desc *desc,
 		 bool use_dma_key,
 		 struct iser_mem_reg *reg)
 {
 	struct iser_device *device = task->iser_conn->ib_conn.device;

 	if (use_dma_key)
 		return iser_reg_dma(device, mem, reg);

 	return iser_fast_reg_mr(task, mem, &desc->rsc, reg);
 }

 int iser_reg_mem_fastreg(struct iscsi_iser_task *task,
 			 enum iser_data_dir dir,
 			 bool all_imm)
 {
 	struct ib_conn *ib_conn = &task->iser_conn->ib_conn;
 	struct iser_data_buf *mem = &task->data[dir];
 	struct iser_mem_reg *reg = &task->rdma_reg[dir];
 	struct iser_fr_desc *desc = NULL;
 	bool use_dma_key;
 	int err;

 	use_dma_key = mem->dma_nents == 1 && (all_imm || !iser_always_reg) &&
 		      scsi_get_prot_op(task->sc) == SCSI_PROT_NORMAL;

 	if (!use_dma_key) {
 		desc = iser_reg_desc_get_fr(ib_conn);
 		reg->mem_h = desc;
 	}

 	if (scsi_get_prot_op(task->sc) == SCSI_PROT_NORMAL) {
 		err = iser_reg_data_sg(task, mem, desc, use_dma_key, reg);
 		if (unlikely(err))
 			goto err_reg;
 	} else {
 		err = iser_reg_sig_mr(task, mem, &task->prot[dir],
 				      &desc->rsc, reg);
 		if (unlikely(err))
 			goto err_reg;

 		desc->sig_protected = true;
 	}

 	return 0;

 err_reg:
 	if (desc)
 		iser_reg_desc_put_fr(ib_conn, desc);

 	return err;
 }
	/*
	* Copyright (c) 2004, 2005, 2006 Voltaire, Inc. All rights reserved.
	* Copyright (c) 2013-2014 Mellanox Technologies. 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/module.h>
	#include <linux/kernel.h>
	#include <linux/slab.h>
	#include <linux/mm.h>
	#include <linux/highmem.h>
	#include <linux/scatterlist.h>

	#include "iscsi_iser.h"

	void iser_reg_comp(struct ib_cq cq, struct ib_wc wc)
	{
	iser_err_comp(wc, "memreg");
	}

	static struct iser_fr_desc *
	iser_reg_desc_get_fr(struct ib_conn *ib_conn)
	{
	struct iser_fr_pool *fr_pool = &ib_conn->fr_pool;
	struct iser_fr_desc *desc;
	unsigned long flags;

	spin_lock_irqsave(&fr_pool->lock, flags);
	desc = list_first_entry(&fr_pool->list,
	struct iser_fr_desc, list);
	list_del(&desc->list);
	spin_unlock_irqrestore(&fr_pool->lock, flags);

	return desc;
	}

	static void
	iser_reg_desc_put_fr(struct ib_conn *ib_conn,
	struct iser_fr_desc *desc)
	{
	struct iser_fr_pool *fr_pool = &ib_conn->fr_pool;
	unsigned long flags;

	spin_lock_irqsave(&fr_pool->lock, flags);
	list_add(&desc->list, &fr_pool->list);
	spin_unlock_irqrestore(&fr_pool->lock, flags);
	}

	int iser_dma_map_task_data(struct iscsi_iser_task *iser_task,
	struct iser_data_buf *data,
	enum iser_data_dir iser_dir,
	enum dma_data_direction dma_dir)
	{
	struct ib_device *dev;

	iser_task->dir[iser_dir] = 1;
	dev = iser_task->iser_conn->ib_conn.device->ib_device;

	data->dma_nents = ib_dma_map_sg(dev, data->sg, data->size, dma_dir);
	if (unlikely(data->dma_nents == 0)) {
	iser_err("dma_map_sg failed!!!\n");
	return -EINVAL;
	}
	return 0;
	}

	void iser_dma_unmap_task_data(struct iscsi_iser_task *iser_task,
	struct iser_data_buf *data,
	enum dma_data_direction dir)
	{
	struct ib_device *dev;

	dev = iser_task->iser_conn->ib_conn.device->ib_device;
	ib_dma_unmap_sg(dev, data->sg, data->size, dir);
	}

	static int
	iser_reg_dma(struct iser_device device, struct iser_data_buf mem,
	struct iser_mem_reg *reg)
	{
	struct scatterlist *sg = mem->sg;

	reg->sge.lkey = device->pd->local_dma_lkey;
	/*
	* FIXME: rework the registration code path to differentiate
	* rkey/lkey use cases
	*/

	if (device->pd->flags & IB_PD_UNSAFE_GLOBAL_RKEY)
	reg->rkey = device->pd->unsafe_global_rkey;
	else
	reg->rkey = 0;
	reg->sge.addr = sg_dma_address(&sg[0]);
	reg->sge.length = sg_dma_len(&sg[0]);

	iser_dbg("Single DMA entry: lkey=0x%x, rkey=0x%x, addr=0x%llx,"
	" length=0x%x\n", reg->sge.lkey, reg->rkey,
	reg->sge.addr, reg->sge.length);

	return 0;
	}

	void iser_unreg_mem_fastreg(struct iscsi_iser_task *iser_task,
	enum iser_data_dir cmd_dir)
	{
	struct iser_mem_reg *reg = &iser_task->rdma_reg[cmd_dir];
	struct iser_fr_desc *desc;
	struct ib_mr_status mr_status;

	desc = reg->mem_h;
	if (!desc)
	return;

	/*
	* The signature MR cannot be invalidated and reused without checking.
	* libiscsi calls the check_protection transport handler only if
	* SCSI-Response is received. And the signature MR is not checked if
	* the task is completed for some other reason like a timeout or error
	* handling. That's why we must check the signature MR here before
	* putting it to the free pool.
	*/
	if (unlikely(desc->sig_protected)) {
	desc->sig_protected = false;
	ib_check_mr_status(desc->rsc.sig_mr, IB_MR_CHECK_SIG_STATUS,
	&mr_status);
	}
	iser_reg_desc_put_fr(&iser_task->iser_conn->ib_conn, reg->mem_h);
	reg->mem_h = NULL;
	}

	static void
	iser_set_dif_domain(struct scsi_cmnd sc, struct ib_sig_domain domain)
	{
	domain->sig_type = IB_SIG_TYPE_T10_DIF;
	domain->sig.dif.pi_interval = scsi_prot_interval(sc);
	domain->sig.dif.ref_tag = t10_pi_ref_tag(sc->request);
	/*
	* At the moment we hard code those, but in the future
	* we will take them from sc.
	*/
	domain->sig.dif.apptag_check_mask = 0xffff;
	domain->sig.dif.app_escape = true;
	domain->sig.dif.ref_escape = true;
	if (sc->prot_flags & SCSI_PROT_REF_INCREMENT)
	domain->sig.dif.ref_remap = true;
	};

	static int
	iser_set_sig_attrs(struct scsi_cmnd sc, struct ib_sig_attrs sig_attrs)
	{
	switch (scsi_get_prot_op(sc)) {
	case SCSI_PROT_WRITE_INSERT:
	case SCSI_PROT_READ_STRIP:
	sig_attrs->mem.sig_type = IB_SIG_TYPE_NONE;
	iser_set_dif_domain(sc, &sig_attrs->wire);
	sig_attrs->wire.sig.dif.bg_type = IB_T10DIF_CRC;
	break;
	case SCSI_PROT_READ_INSERT:
	case SCSI_PROT_WRITE_STRIP:
	sig_attrs->wire.sig_type = IB_SIG_TYPE_NONE;
	iser_set_dif_domain(sc, &sig_attrs->mem);
	sig_attrs->mem.sig.dif.bg_type = sc->prot_flags & SCSI_PROT_IP_CHECKSUM ?
	IB_T10DIF_CSUM : IB_T10DIF_CRC;
	break;
	case SCSI_PROT_READ_PASS:
	case SCSI_PROT_WRITE_PASS:
	iser_set_dif_domain(sc, &sig_attrs->wire);
	sig_attrs->wire.sig.dif.bg_type = IB_T10DIF_CRC;
	iser_set_dif_domain(sc, &sig_attrs->mem);
	sig_attrs->mem.sig.dif.bg_type = sc->prot_flags & SCSI_PROT_IP_CHECKSUM ?
	IB_T10DIF_CSUM : IB_T10DIF_CRC;
	break;
	default:
	iser_err("Unsupported PI operation %d\n",
	scsi_get_prot_op(sc));
	return -EINVAL;
	}

	return 0;
	}

	static inline void
	iser_set_prot_checks(struct scsi_cmnd sc, u8 mask)
	{
	*mask = 0;
	if (sc->prot_flags & SCSI_PROT_REF_CHECK)
	*mask \|= IB_SIG_CHECK_REFTAG;
	if (sc->prot_flags & SCSI_PROT_GUARD_CHECK)
	*mask \|= IB_SIG_CHECK_GUARD;
	}

	static inline void
	iser_inv_rkey(struct ib_send_wr *inv_wr,
	struct ib_mr *mr,
	struct ib_cqe *cqe,
	struct ib_send_wr *next_wr)
	{
	inv_wr->opcode = IB_WR_LOCAL_INV;
	inv_wr->wr_cqe = cqe;
	inv_wr->ex.invalidate_rkey = mr->rkey;
	inv_wr->send_flags = 0;
	inv_wr->num_sge = 0;
	inv_wr->next = next_wr;
	}

	static int
	iser_reg_sig_mr(struct iscsi_iser_task *iser_task,
	struct iser_data_buf *mem,
	struct iser_data_buf *sig_mem,
	struct iser_reg_resources *rsc,
	struct iser_mem_reg *sig_reg)
	{
	struct iser_tx_desc *tx_desc = &iser_task->desc;
	struct ib_cqe *cqe = &iser_task->iser_conn->ib_conn.reg_cqe;
	struct ib_mr *mr = rsc->sig_mr;
	struct ib_sig_attrs *sig_attrs = mr->sig_attrs;
	struct ib_reg_wr *wr = &tx_desc->reg_wr;
	int ret;

	memset(sig_attrs, 0, sizeof(*sig_attrs));
	ret = iser_set_sig_attrs(iser_task->sc, sig_attrs);
	if (ret)
	goto err;

	iser_set_prot_checks(iser_task->sc, &sig_attrs->check_mask);

	if (rsc->mr_valid)
	iser_inv_rkey(&tx_desc->inv_wr, mr, cqe, &wr->wr);

	ib_update_fast_reg_key(mr, ib_inc_rkey(mr->rkey));

	ret = ib_map_mr_sg_pi(mr, mem->sg, mem->dma_nents, NULL,
	sig_mem->sg, sig_mem->dma_nents, NULL, SZ_4K);
	if (unlikely(ret)) {
	iser_err("failed to map PI sg (%d)\n",
	mem->dma_nents + sig_mem->dma_nents);
	goto err;
	}

	memset(wr, 0, sizeof(*wr));
	wr->wr.next = &tx_desc->send_wr;
	wr->wr.opcode = IB_WR_REG_MR_INTEGRITY;
	wr->wr.wr_cqe = cqe;
	wr->wr.num_sge = 0;
	wr->wr.send_flags = 0;
	wr->mr = mr;
	wr->key = mr->rkey;
	wr->access = IB_ACCESS_LOCAL_WRITE \|
	IB_ACCESS_REMOTE_READ \|
	IB_ACCESS_REMOTE_WRITE;
	rsc->mr_valid = 1;

	sig_reg->sge.lkey = mr->lkey;
	sig_reg->rkey = mr->rkey;
	sig_reg->sge.addr = mr->iova;
	sig_reg->sge.length = mr->length;

	iser_dbg("lkey=0x%x rkey=0x%x addr=0x%llx length=%u\n",
	sig_reg->sge.lkey, sig_reg->rkey, sig_reg->sge.addr,
	sig_reg->sge.length);
	err:
	return ret;
	}

	static int iser_fast_reg_mr(struct iscsi_iser_task *iser_task,
	struct iser_data_buf *mem,
	struct iser_reg_resources *rsc,
	struct iser_mem_reg *reg)
	{
	struct iser_tx_desc *tx_desc = &iser_task->desc;
	struct ib_cqe *cqe = &iser_task->iser_conn->ib_conn.reg_cqe;
	struct ib_mr *mr = rsc->mr;
	struct ib_reg_wr *wr = &tx_desc->reg_wr;
	int n;

	if (rsc->mr_valid)
	iser_inv_rkey(&tx_desc->inv_wr, mr, cqe, &wr->wr);

	ib_update_fast_reg_key(mr, ib_inc_rkey(mr->rkey));

	n = ib_map_mr_sg(mr, mem->sg, mem->dma_nents, NULL, SZ_4K);
	if (unlikely(n != mem->dma_nents)) {
	iser_err("failed to map sg (%d/%d)\n",
	n, mem->dma_nents);
	return n < 0 ? n : -EINVAL;
	}

	wr->wr.next = &tx_desc->send_wr;
	wr->wr.opcode = IB_WR_REG_MR;
	wr->wr.wr_cqe = cqe;
	wr->wr.send_flags = 0;
	wr->wr.num_sge = 0;
	wr->mr = mr;
	wr->key = mr->rkey;
	wr->access = IB_ACCESS_LOCAL_WRITE \|
	IB_ACCESS_REMOTE_WRITE \|
	IB_ACCESS_REMOTE_READ;

	rsc->mr_valid = 1;

	reg->sge.lkey = mr->lkey;
	reg->rkey = mr->rkey;
	reg->sge.addr = mr->iova;
	reg->sge.length = mr->length;

	iser_dbg("lkey=0x%x rkey=0x%x addr=0x%llx length=0x%x\n",
	reg->sge.lkey, reg->rkey, reg->sge.addr, reg->sge.length);

	return 0;
	}

	static int
	iser_reg_data_sg(struct iscsi_iser_task *task,
	struct iser_data_buf *mem,
	struct iser_fr_desc *desc,
	bool use_dma_key,
	struct iser_mem_reg *reg)
	{
	struct iser_device *device = task->iser_conn->ib_conn.device;

	if (use_dma_key)
	return iser_reg_dma(device, mem, reg);

	return iser_fast_reg_mr(task, mem, &desc->rsc, reg);
	}

	int iser_reg_mem_fastreg(struct iscsi_iser_task *task,
	enum iser_data_dir dir,
	bool all_imm)
	{
	struct ib_conn *ib_conn = &task->iser_conn->ib_conn;
	struct iser_data_buf *mem = &task->data[dir];
	struct iser_mem_reg *reg = &task->rdma_reg[dir];
	struct iser_fr_desc *desc = NULL;
	bool use_dma_key;
	int err;

	use_dma_key = mem->dma_nents == 1 && (all_imm \|\| !iser_always_reg) &&
	scsi_get_prot_op(task->sc) == SCSI_PROT_NORMAL;

	if (!use_dma_key) {
	desc = iser_reg_desc_get_fr(ib_conn);
	reg->mem_h = desc;
	}

	if (scsi_get_prot_op(task->sc) == SCSI_PROT_NORMAL) {
	err = iser_reg_data_sg(task, mem, desc, use_dma_key, reg);
	if (unlikely(err))
	goto err_reg;
	} else {
	err = iser_reg_sig_mr(task, mem, &task->prot[dir],
	&desc->rsc, reg);
	if (unlikely(err))
	goto err_reg;

	desc->sig_protected = true;
	}

	return 0;

	err_reg:
	if (desc)
	iser_reg_desc_put_fr(ib_conn, desc);

	return err;
	}