/*
 * 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"

#ifndef HAVE_VIRT_BOUNDARY
#define IS_4K_ALIGNED(addr) ((((unsigned long)addr) & ~(SZ_4K - 1)) == 0)
static void iser_free_bounce_sg(struct iser_data_buf *data)
{
	struct scatterlist *sg;
	int count;

	for_each_sg (data->sg, sg, data->size, count)
		__free_page(sg_page(sg));

	kfree(data->sg);

	data->sg = data->orig_sg;
	data->size = data->orig_size;
	data->orig_sg = NULL;
	data->orig_size = 0;
}

static int iser_alloc_bounce_sg(struct iser_data_buf *data)
{
	struct scatterlist *sg;
	struct page *page;
	unsigned long length = data->data_len;
	int i = 0, nents = DIV_ROUND_UP(length, PAGE_SIZE);

	sg = kcalloc(nents, sizeof(*sg), GFP_ATOMIC);
	if (!sg)
		goto err;

	sg_init_table(sg, nents);
	while (length) {
		u32 page_len = min_t(u32, length, PAGE_SIZE);

		page = alloc_page(GFP_ATOMIC);
		if (!page)
			goto err;

		sg_set_page(&sg[i], page, page_len, 0);
		length -= page_len;
		i++;
	}

	data->orig_sg = data->sg;
	data->orig_size = data->size;
	data->sg = sg;
	data->size = nents;

	return 0;

err:
	for (; i > 0; i--)
		__free_page(sg_page(&sg[i - 1]));
	kfree(sg);

	return -ENOMEM;
}

static void iser_copy_bounce(struct iser_data_buf *data, bool to_buffer)
{
	struct scatterlist *osg, *bsg = data->sg;
	void *oaddr, *baddr;
	unsigned int left = data->data_len;
	unsigned int bsg_off = 0;
	int i;

	for_each_sg (data->orig_sg, osg, data->orig_size, i) {
		unsigned int copy_len, osg_off = 0;

		oaddr = kmap_atomic(sg_page(osg)) + osg->offset;
		copy_len = min(left, osg->length);
		while (copy_len) {
			unsigned int len = min(copy_len, bsg->length - bsg_off);

			baddr = kmap_atomic(sg_page(bsg)) + bsg->offset;

			if (to_buffer)
				memcpy(baddr + bsg_off, oaddr + osg_off, len);
			else
				memcpy(oaddr + osg_off, baddr + bsg_off, len);

			kunmap_atomic(baddr - bsg->offset);
			osg_off += len;
			bsg_off += len;
			copy_len -= len;

			if (bsg_off >= bsg->length) {
				bsg = sg_next(bsg);
				bsg_off = 0;
			}
		}
		kunmap_atomic(oaddr - osg->offset);
		left -= osg_off;
	}
}

static inline void iser_copy_from_bounce(struct iser_data_buf *data)
{
	iser_copy_bounce(data, false);
}

static inline void iser_copy_to_bounce(struct iser_data_buf *data)
{
	iser_copy_bounce(data, true);
}

/**
 * iser_start_rdma_unaligned_sg
 */
static int iser_start_rdma_unaligned_sg(struct iscsi_iser_task *iser_task,
					struct iser_data_buf *data,
					enum iser_data_dir cmd_dir)
{
	struct ib_device *dev = iser_task->iser_conn->ib_conn.device->ib_device;
	int rc;

	rc = iser_alloc_bounce_sg(data);
	if (rc) {
		iser_err("Failed to allocate bounce for data len %lu\n",
			 data->data_len);
		return rc;
	}

	if (cmd_dir == ISER_DIR_OUT)
		iser_copy_to_bounce(data);

	data->dma_nents = ib_dma_map_sg(
		dev, data->sg, data->size,
		(cmd_dir == ISER_DIR_OUT) ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
	if (!data->dma_nents) {
		iser_err("Got dma_nents %d, something went wrong...\n",
			 data->dma_nents);
		rc = -ENOMEM;
		goto err;
	}

	return 0;
err:
	iser_free_bounce_sg(data);
	return rc;
}

/**
 * iser_finalize_rdma_unaligned_sg
 */
void iser_finalize_rdma_unaligned_sg(struct iscsi_iser_task *iser_task,
				     struct iser_data_buf *data,
				     enum iser_data_dir cmd_dir)
{
	struct ib_device *dev = iser_task->iser_conn->ib_conn.device->ib_device;

	ib_dma_unmap_sg(dev, data->sg, data->size,
			(cmd_dir == ISER_DIR_OUT) ? DMA_TO_DEVICE :
						    DMA_FROM_DEVICE);

	if (cmd_dir == ISER_DIR_IN)
		iser_copy_from_bounce(data);

	iser_free_bounce_sg(data);
}

/**
 * iser_data_buf_aligned_len - Tries to determine the maximal correctly aligned
 * for RDMA sub-list of a scatter-gather list of memory buffers, and  returns
 * the number of entries which are aligned correctly. Supports the case where
 * consecutive SG elements are actually fragments of the same physical page.
 */
static int iser_data_buf_aligned_len(struct iser_data_buf *data,
				     struct ib_device *ibdev,
				     unsigned sg_tablesize)
{
	struct scatterlist *sg, *sgl, *next_sg = NULL;
	u64 start_addr, end_addr;
	int i, ret_len, start_check = 0;

	if (data->dma_nents == 1)
		return 1;

	sgl = data->sg;
	start_addr = sg_dma_address(sgl);

	for_each_sg (sgl, sg, data->dma_nents, i) {
		if (start_check && !IS_4K_ALIGNED(start_addr))
			break;

		next_sg = sg_next(sg);
		if (!next_sg)
			break;

		end_addr = start_addr + sg_dma_len(sg);
		start_addr = sg_dma_address(next_sg);

		if (end_addr == start_addr) {
			start_check = 0;
			continue;
		} else
			start_check = 1;

		if (!IS_4K_ALIGNED(end_addr))
			break;
	}
	ret_len = (next_sg) ? i : i + 1;

	if (unlikely(ret_len != data->dma_nents))
		iser_warn("rdma alignment violation (%d/%d aligned)\n", ret_len,
			  data->dma_nents);

	return ret_len;
}
#endif

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);
}

#ifndef HAVE_VIRT_BOUNDARY
static void iser_data_buf_dump(struct iser_data_buf *data,
			       struct ib_device *ibdev)
{
	struct scatterlist *sg;
	int i;

	for_each_sg(data->sg, sg, data->dma_nents, i)
		iser_dbg("sg[%d] dma_addr:0x%lX page:0x%p "
			 "off:0x%x sz:0x%x dma_len:0x%x\n",
			 i, (unsigned long)sg_dma_address(sg),
			 sg_page(sg), sg->offset, sg->length, sg_dma_len(sg));
}

static int fall_to_bounce_buf(struct iscsi_iser_task *iser_task,
			      struct iser_data_buf *mem,
			      enum iser_data_dir cmd_dir)
{
	struct iscsi_conn *iscsi_conn = iser_task->iser_conn->iscsi_conn;
	struct iser_device *device = iser_task->iser_conn->ib_conn.device;

	iscsi_conn->fmr_unalign_cnt++;

	if (iser_debug_level > 0)
		iser_data_buf_dump(mem, device->ib_device);

	/* unmap the command data before accessing it */
	iser_dma_unmap_task_data(iser_task, mem,
				 (cmd_dir == ISER_DIR_OUT) ? DMA_TO_DEVICE :
							     DMA_FROM_DEVICE);

	/* allocate copy buf, if we are writing, copy the */
	/* unaligned scatterlist, dma map the copy        */
	if (iser_start_rdma_unaligned_sg(iser_task, mem, cmd_dir) != 0)
		return -ENOMEM;

	return 0;
}

static int iser_handle_unaligned_buf(struct iscsi_iser_task *task,
				     struct iser_data_buf *mem,
				     enum iser_data_dir dir)
{
	struct iser_conn *iser_conn = task->iser_conn;
	struct iser_device *device = iser_conn->ib_conn.device;
	int err, aligned_len;

	aligned_len = iser_data_buf_aligned_len(mem, device->ib_device,
						iser_conn->scsi_sg_tablesize);
	if (aligned_len != mem->dma_nents) {
		err = fall_to_bounce_buf(task, mem, dir);
		if (err)
			return err;
	}

	return 0;
}
#endif

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;
#ifdef HAVE_SCSI_CMND_PROT_FLAGS
	domain->sig.dif.pi_interval = scsi_prot_interval(sc);
#ifdef HAVE_T10_PI_REF_TAG
	domain->sig.dif.ref_tag = t10_pi_ref_tag(sc->request);
#else
	domain->sig.dif.ref_tag = scsi_prot_ref_tag(sc);
#endif
#else
	domain->sig.dif.pi_interval = sc->device->sector_size;
	domain->sig.dif.ref_tag = scsi_get_lba(sc) & 0xffffffff;
#endif
	/*
	 * 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;
#ifdef HAVE_SCSI_CMND_PROT_FLAGS
	if (sc->prot_flags & SCSI_PROT_REF_INCREMENT)
		domain->sig.dif.ref_remap = true;
#else
	if (scsi_get_prot_type(sc) == SCSI_PROT_DIF_TYPE1 ||
	    scsi_get_prot_type(sc) == SCSI_PROT_DIF_TYPE2)
		domain->sig.dif.ref_remap = true;
#endif
};

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);
#ifdef HAVE_SCSI_CMND_PROT_FLAGS
		/* WA for #963642: DIX always use SCSI_PROT_IP_CHECKSUM */
		sc->prot_flags |= SCSI_PROT_IP_CHECKSUM;
		sig_attrs->mem.sig.dif.bg_type = sc->prot_flags & SCSI_PROT_IP_CHECKSUM ?
						IB_T10DIF_CSUM : IB_T10DIF_CRC;
#else
		sig_attrs->mem.sig.dif.bg_type =
			iser_pi_guard ? IB_T10DIF_CSUM : IB_T10DIF_CRC;
#endif
		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);
#ifdef HAVE_SCSI_CMND_PROT_FLAGS
		/* WA for #963642: DIX always use SCSI_PROT_IP_CHECKSUM */
		sc->prot_flags |= SCSI_PROT_IP_CHECKSUM;
		sig_attrs->mem.sig.dif.bg_type = sc->prot_flags & SCSI_PROT_IP_CHECKSUM ?
						IB_T10DIF_CSUM : IB_T10DIF_CRC;
#else
		sig_attrs->mem.sig.dif.bg_type =
			iser_pi_guard ? IB_T10DIF_CSUM : IB_T10DIF_CRC;
#endif
		break;
	default:
		iser_err("Unsupported PI operation %d\n",
			 scsi_get_prot_op(sc));
		return -EINVAL;
	}

	return 0;
}

#ifdef HAVE_SCSI_CMND_PROT_FLAGS
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;
}
#else
static int
iser_set_prot_checks(struct scsi_cmnd *sc, u8 *mask)
{
	switch (scsi_get_prot_type(sc)) {
	case SCSI_PROT_DIF_TYPE0:
		*mask = 0x0;
		break;
	case SCSI_PROT_DIF_TYPE1:
	case SCSI_PROT_DIF_TYPE2:
		*mask = IB_SIG_CHECK_GUARD | IB_SIG_CHECK_REFTAG;
		break;
	case SCSI_PROT_DIF_TYPE3:
		*mask = IB_SIG_CHECK_GUARD;
		break;
	default:
		iser_err("Unsupported protection type %d\n",
			 scsi_get_prot_type(sc));
		return -EINVAL;
	}

	return 0;
}
#endif

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;
#ifdef HAVE_SCSI_CMND_PROT_FLAGS
	iser_set_prot_checks(iser_task->sc, &sig_attrs->check_mask);
#else
	ret = iser_set_prot_checks(iser_task->sc, &sig_attrs->check_mask);
	if (ret)
		goto err;
#endif

	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;
#ifndef HAVE_VIRT_BOUNDARY
	struct ib_device *ib_dev = ib_conn->device->ib_device;
#endif
	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;

#ifndef HAVE_VIRT_BOUNDARY
	if (!(ib_dev->attrs.device_cap_flags & IB_DEVICE_SG_GAPS_REG)) {
		err = iser_handle_unaligned_buf(task, mem, dir);
		if (unlikely(err))
			return err;
	}
#endif
	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);
#ifndef HAVE_VIRT_BOUNDARY
	if (mem->orig_sg)
		iser_free_bounce_sg(mem);
#endif

	return err;
}

