drivers/scsi/libsrp.c - maze/linux - Git at Google

 /*
  * SCSI RDMA Protocol lib functions
  *
  * Copyright (C) 2006 FUJITA Tomonori <tomof@acm.org>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
  * published by the Free Software Foundation; either version 2 of the
  * License, or (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful, but
  * WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  * 02110-1301 USA
  */
 #include <linux/err.h>
 #include <linux/kfifo.h>
 #include <linux/scatterlist.h>
 #include <linux/dma-mapping.h>
 #include <scsi/scsi.h>
 #include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_tcq.h>
 #include <scsi/scsi_tgt.h>
 #include <scsi/srp.h>
 #include <scsi/libsrp.h>

 enum srp_task_attributes {
 	SRP_SIMPLE_TASK = 0,
 	SRP_HEAD_TASK = 1,
 	SRP_ORDERED_TASK = 2,
 	SRP_ACA_TASK = 4
 };

 /* tmp - will replace with SCSI logging stuff */
 #define eprintk(fmt, args...)					\
 do {								\
 	printk("%s(%d) " fmt, __func__, __LINE__, ##args);	\
 } while (0)
 /* #define dprintk eprintk */
 #define dprintk(fmt, args...)

 static int srp_iu_pool_alloc(struct srp_queue *q, size_t max,
 			     struct srp_buf **ring)
 {
 	int i;
 	struct iu_entry *iue;

 	q->pool = kcalloc(max, sizeof(struct iu_entry *), GFP_KERNEL);
 	if (!q->pool)
 		return -ENOMEM;
 	q->items = kcalloc(max, sizeof(struct iu_entry), GFP_KERNEL);
 	if (!q->items)
 		goto free_pool;

 	spin_lock_init(&q->lock);
 	kfifo_init(&q->queue, (void *) q->pool, max * sizeof(void *));

 	for (i = 0, iue = q->items; i < max; i++) {
 		kfifo_in(&q->queue, (void *) &iue, sizeof(void *));
 		iue->sbuf = ring[i];
 		iue++;
 	}
 	return 0;

 	kfree(q->items);
 free_pool:
 	kfree(q->pool);
 	return -ENOMEM;
 }

 static void srp_iu_pool_free(struct srp_queue *q)
 {
 	kfree(q->items);
 	kfree(q->pool);
 }

 static struct srp_buf **srp_ring_alloc(struct device *dev,
 				       size_t max, size_t size)
 {
 	int i;
 	struct srp_buf **ring;

 	ring = kcalloc(max, sizeof(struct srp_buf *), GFP_KERNEL);
 	if (!ring)
 		return NULL;

 	for (i = 0; i < max; i++) {
 		ring[i] = kzalloc(sizeof(struct srp_buf), GFP_KERNEL);
 		if (!ring[i])
 			goto out;
 		ring[i]->buf = dma_alloc_coherent(dev, size, &ring[i]->dma,
 						  GFP_KERNEL);
 		if (!ring[i]->buf)
 			goto out;
 	}
 	return ring;

 out:
 	for (i = 0; i < max && ring[i]; i++) {
 		if (ring[i]->buf)
 			dma_free_coherent(dev, size, ring[i]->buf, ring[i]->dma);
 		kfree(ring[i]);
 	}
 	kfree(ring);

 	return NULL;
 }

 static void srp_ring_free(struct device *dev, struct srp_buf **ring, size_t max,
 			  size_t size)
 {
 	int i;

 	for (i = 0; i < max; i++) {
 		dma_free_coherent(dev, size, ring[i]->buf, ring[i]->dma);
 		kfree(ring[i]);
 	}
 	kfree(ring);
 }

 int srp_target_alloc(struct srp_target *target, struct device *dev,
 		     size_t nr, size_t iu_size)
 {
 	int err;

 	spin_lock_init(&target->lock);
 	INIT_LIST_HEAD(&target->cmd_queue);

 	target->dev = dev;
 	dev_set_drvdata(target->dev, target);

 	target->srp_iu_size = iu_size;
 	target->rx_ring_size = nr;
 	target->rx_ring = srp_ring_alloc(target->dev, nr, iu_size);
 	if (!target->rx_ring)
 		return -ENOMEM;
 	err = srp_iu_pool_alloc(&target->iu_queue, nr, target->rx_ring);
 	if (err)
 		goto free_ring;

 	return 0;

 free_ring:
 	srp_ring_free(target->dev, target->rx_ring, nr, iu_size);
 	return -ENOMEM;
 }
 EXPORT_SYMBOL_GPL(srp_target_alloc);

 void srp_target_free(struct srp_target *target)
 {
 	srp_ring_free(target->dev, target->rx_ring, target->rx_ring_size,
 		      target->srp_iu_size);
 	srp_iu_pool_free(&target->iu_queue);
 }
 EXPORT_SYMBOL_GPL(srp_target_free);

 struct iu_entry *srp_iu_get(struct srp_target *target)
 {
 	struct iu_entry *iue = NULL;

 	if (kfifo_out_locked(&target->iu_queue.queue, (void *) &iue,
 		sizeof(void *), &target->iu_queue.lock) != sizeof(void *)) {
 			WARN_ONCE(1, "unexpected fifo state");
 			return NULL;
 	}
 	if (!iue)
 		return iue;
 	iue->target = target;
 	INIT_LIST_HEAD(&iue->ilist);
 	iue->flags = 0;
 	return iue;
 }
 EXPORT_SYMBOL_GPL(srp_iu_get);

 void srp_iu_put(struct iu_entry *iue)
 {
 	kfifo_in_locked(&iue->target->iu_queue.queue, (void *) &iue,
 			sizeof(void *), &iue->target->iu_queue.lock);
 }
 EXPORT_SYMBOL_GPL(srp_iu_put);

 static int srp_direct_data(struct scsi_cmnd *sc, struct srp_direct_buf *md,
 			   enum dma_data_direction dir, srp_rdma_t rdma_io,
 			   int dma_map, int ext_desc)
 {
 	struct iu_entry *iue = NULL;
 	struct scatterlist *sg = NULL;
 	int err, nsg = 0, len;

 	if (dma_map) {
 		iue = (struct iu_entry *) sc->SCp.ptr;
 		sg = scsi_sglist(sc);

 		dprintk("%p %u %u %d\n", iue, scsi_bufflen(sc),
 			md->len, scsi_sg_count(sc));

 		nsg = dma_map_sg(iue->target->dev, sg, scsi_sg_count(sc),
 				 DMA_BIDIRECTIONAL);
 		if (!nsg) {
 			printk("fail to map %p %d\n", iue, scsi_sg_count(sc));
 			return 0;
 		}
 		len = min(scsi_bufflen(sc), md->len);
 	} else
 		len = md->len;

 	err = rdma_io(sc, sg, nsg, md, 1, dir, len);

 	if (dma_map)
 		dma_unmap_sg(iue->target->dev, sg, nsg, DMA_BIDIRECTIONAL);

 	return err;
 }

 static int srp_indirect_data(struct scsi_cmnd *sc, struct srp_cmd *cmd,
 			     struct srp_indirect_buf *id,
 			     enum dma_data_direction dir, srp_rdma_t rdma_io,
 			     int dma_map, int ext_desc)
 {
 	struct iu_entry *iue = NULL;
 	struct srp_direct_buf *md = NULL;
 	struct scatterlist dummy, *sg = NULL;
 	dma_addr_t token = 0;
 	int err = 0;
 	int nmd, nsg = 0, len;

 	if (dma_map || ext_desc) {
 		iue = (struct iu_entry *) sc->SCp.ptr;
 		sg = scsi_sglist(sc);

 		dprintk("%p %u %u %d %d\n",
 			iue, scsi_bufflen(sc), id->len,
 			cmd->data_in_desc_cnt, cmd->data_out_desc_cnt);
 	}

 	nmd = id->table_desc.len / sizeof(struct srp_direct_buf);

 	if ((dir == DMA_FROM_DEVICE && nmd == cmd->data_in_desc_cnt) ||
 	    (dir == DMA_TO_DEVICE && nmd == cmd->data_out_desc_cnt)) {
 		md = &id->desc_list[0];
 		goto rdma;
 	}

 	if (ext_desc && dma_map) {
 		md = dma_alloc_coherent(iue->target->dev, id->table_desc.len,
 				&token, GFP_KERNEL);
 		if (!md) {
 			eprintk("Can't get dma memory %u\n", id->table_desc.len);
 			return -ENOMEM;
 		}

 		sg_init_one(&dummy, md, id->table_desc.len);
 		sg_dma_address(&dummy) = token;
 		sg_dma_len(&dummy) = id->table_desc.len;
 		err = rdma_io(sc, &dummy, 1, &id->table_desc, 1, DMA_TO_DEVICE,
 			      id->table_desc.len);
 		if (err) {
 			eprintk("Error copying indirect table %d\n", err);
 			goto free_mem;
 		}
 	} else {
 		eprintk("This command uses external indirect buffer\n");
 		return -EINVAL;
 	}

 rdma:
 	if (dma_map) {
 		nsg = dma_map_sg(iue->target->dev, sg, scsi_sg_count(sc),
 				 DMA_BIDIRECTIONAL);
 		if (!nsg) {
 			eprintk("fail to map %p %d\n", iue, scsi_sg_count(sc));
 			err = -EIO;
 			goto free_mem;
 		}
 		len = min(scsi_bufflen(sc), id->len);
 	} else
 		len = id->len;

 	err = rdma_io(sc, sg, nsg, md, nmd, dir, len);

 	if (dma_map)
 		dma_unmap_sg(iue->target->dev, sg, nsg, DMA_BIDIRECTIONAL);

 free_mem:
 	if (token && dma_map)
 		dma_free_coherent(iue->target->dev, id->table_desc.len, md, token);

 	return err;
 }

 static int data_out_desc_size(struct srp_cmd *cmd)
 {
 	int size = 0;
 	u8 fmt = cmd->buf_fmt >> 4;

 	switch (fmt) {
 	case SRP_NO_DATA_DESC:
 		break;
 	case SRP_DATA_DESC_DIRECT:
 		size = sizeof(struct srp_direct_buf);
 		break;
 	case SRP_DATA_DESC_INDIRECT:
 		size = sizeof(struct srp_indirect_buf) +
 			sizeof(struct srp_direct_buf) * cmd->data_out_desc_cnt;
 		break;
 	default:
 		eprintk("client error. Invalid data_out_format %x\n", fmt);
 		break;
 	}
 	return size;
 }

 /*
  * TODO: this can be called multiple times for a single command if it
  * has very long data.
  */
 int srp_transfer_data(struct scsi_cmnd *sc, struct srp_cmd *cmd,
 		      srp_rdma_t rdma_io, int dma_map, int ext_desc)
 {
 	struct srp_direct_buf *md;
 	struct srp_indirect_buf *id;
 	enum dma_data_direction dir;
 	int offset, err = 0;
 	u8 format;

 	offset = cmd->add_cdb_len * 4;

 	dir = srp_cmd_direction(cmd);
 	if (dir == DMA_FROM_DEVICE)
 		offset += data_out_desc_size(cmd);

 	if (dir == DMA_TO_DEVICE)
 		format = cmd->buf_fmt >> 4;
 	else
 		format = cmd->buf_fmt & ((1U << 4) - 1);

 	switch (format) {
 	case SRP_NO_DATA_DESC:
 		break;
 	case SRP_DATA_DESC_DIRECT:
 		md = (struct srp_direct_buf *)
 			(cmd->add_data + offset);
 		err = srp_direct_data(sc, md, dir, rdma_io, dma_map, ext_desc);
 		break;
 	case SRP_DATA_DESC_INDIRECT:
 		id = (struct srp_indirect_buf *)
 			(cmd->add_data + offset);
 		err = srp_indirect_data(sc, cmd, id, dir, rdma_io, dma_map,
 					ext_desc);
 		break;
 	default:
 		eprintk("Unknown format %d %x\n", dir, format);
 		err = -EINVAL;
 	}

 	return err;
 }
 EXPORT_SYMBOL_GPL(srp_transfer_data);

 static int vscsis_data_length(struct srp_cmd *cmd, enum dma_data_direction dir)
 {
 	struct srp_direct_buf *md;
 	struct srp_indirect_buf *id;
 	int len = 0, offset = cmd->add_cdb_len * 4;
 	u8 fmt;

 	if (dir == DMA_TO_DEVICE)
 		fmt = cmd->buf_fmt >> 4;
 	else {
 		fmt = cmd->buf_fmt & ((1U << 4) - 1);
 		offset += data_out_desc_size(cmd);
 	}

 	switch (fmt) {
 	case SRP_NO_DATA_DESC:
 		break;
 	case SRP_DATA_DESC_DIRECT:
 		md = (struct srp_direct_buf *) (cmd->add_data + offset);
 		len = md->len;
 		break;
 	case SRP_DATA_DESC_INDIRECT:
 		id = (struct srp_indirect_buf *) (cmd->add_data + offset);
 		len = id->len;
 		break;
 	default:
 		eprintk("invalid data format %x\n", fmt);
 		break;
 	}
 	return len;
 }

 int srp_cmd_queue(struct Scsi_Host *shost, struct srp_cmd *cmd, void *info,
 		  u64 itn_id, u64 addr)
 {
 	enum dma_data_direction dir;
 	struct scsi_cmnd *sc;
 	int tag, len, err;

 	switch (cmd->task_attr) {
 	case SRP_SIMPLE_TASK:
 		tag = MSG_SIMPLE_TAG;
 		break;
 	case SRP_ORDERED_TASK:
 		tag = MSG_ORDERED_TAG;
 		break;
 	case SRP_HEAD_TASK:
 		tag = MSG_HEAD_TAG;
 		break;
 	default:
 		eprintk("Task attribute %d not supported\n", cmd->task_attr);
 		tag = MSG_ORDERED_TAG;
 	}

 	dir = srp_cmd_direction(cmd);
 	len = vscsis_data_length(cmd, dir);

 	dprintk("%p %x %lx %d %d %d %llx\n", info, cmd->cdb[0],
 		cmd->lun, dir, len, tag, (unsigned long long) cmd->tag);

 	sc = scsi_host_get_command(shost, dir, GFP_KERNEL);
 	if (!sc)
 		return -ENOMEM;

 	sc->SCp.ptr = info;
 	memcpy(sc->cmnd, cmd->cdb, MAX_COMMAND_SIZE);
 	sc->sdb.length = len;
 	sc->sdb.table.sgl = (void *) (unsigned long) addr;
 	sc->tag = tag;
 	err = scsi_tgt_queue_command(sc, itn_id, (struct scsi_lun *)&cmd->lun,
 				     cmd->tag);
 	if (err)
 		scsi_host_put_command(shost, sc);

 	return err;
 }
 EXPORT_SYMBOL_GPL(srp_cmd_queue);

 MODULE_DESCRIPTION("SCSI RDMA Protocol lib functions");
 MODULE_AUTHOR("FUJITA Tomonori");
 MODULE_LICENSE("GPL");
	/*
	* SCSI RDMA Protocol lib functions
	*
	* Copyright (C) 2006 FUJITA Tomonori <tomof@acm.org>
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License as
	* published by the Free Software Foundation; either version 2 of the
	* License, or (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful, but
	* WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
	* 02110-1301 USA
	*/
	#include <linux/err.h>
	#include <linux/kfifo.h>
	#include <linux/scatterlist.h>
	#include <linux/dma-mapping.h>
	#include <scsi/scsi.h>
	#include <scsi/scsi_cmnd.h>
	#include <scsi/scsi_tcq.h>
	#include <scsi/scsi_tgt.h>
	#include <scsi/srp.h>
	#include <scsi/libsrp.h>

	enum srp_task_attributes {
	SRP_SIMPLE_TASK = 0,
	SRP_HEAD_TASK = 1,
	SRP_ORDERED_TASK = 2,
	SRP_ACA_TASK = 4
	};

	/* tmp - will replace with SCSI logging stuff */
	#define eprintk(fmt, args...) \
	do { \
	printk("%s(%d) " fmt, __func__, __LINE__, ##args); \
	} while (0)
	/* #define dprintk eprintk */
	#define dprintk(fmt, args...)

	static int srp_iu_pool_alloc(struct srp_queue *q, size_t max,
	struct srp_buf **ring)
	{
	int i;
	struct iu_entry *iue;

	q->pool = kcalloc(max, sizeof(struct iu_entry *), GFP_KERNEL);
	if (!q->pool)
	return -ENOMEM;
	q->items = kcalloc(max, sizeof(struct iu_entry), GFP_KERNEL);
	if (!q->items)
	goto free_pool;

	spin_lock_init(&q->lock);
	kfifo_init(&q->queue, (void ) q->pool, max sizeof(void *));

	for (i = 0, iue = q->items; i < max; i++) {
	kfifo_in(&q->queue, (void ) &iue, sizeof(void ));
	iue->sbuf = ring[i];
	iue++;
	}
	return 0;

	kfree(q->items);
	free_pool:
	kfree(q->pool);
	return -ENOMEM;
	}

	static void srp_iu_pool_free(struct srp_queue *q)
	{
	kfree(q->items);
	kfree(q->pool);
	}

	static struct srp_buf *srp_ring_alloc(struct device dev,
	size_t max, size_t size)
	{
	int i;
	struct srp_buf **ring;

	ring = kcalloc(max, sizeof(struct srp_buf *), GFP_KERNEL);
	if (!ring)
	return NULL;

	for (i = 0; i < max; i++) {
	ring[i] = kzalloc(sizeof(struct srp_buf), GFP_KERNEL);
	if (!ring[i])
	goto out;
	ring[i]->buf = dma_alloc_coherent(dev, size, &ring[i]->dma,
	GFP_KERNEL);
	if (!ring[i]->buf)
	goto out;
	}
	return ring;

	out:
	for (i = 0; i < max && ring[i]; i++) {
	if (ring[i]->buf)
	dma_free_coherent(dev, size, ring[i]->buf, ring[i]->dma);
	kfree(ring[i]);
	}
	kfree(ring);

	return NULL;
	}

	static void srp_ring_free(struct device dev, struct srp_buf *ring, size_t max,
	size_t size)
	{
	int i;

	for (i = 0; i < max; i++) {
	dma_free_coherent(dev, size, ring[i]->buf, ring[i]->dma);
	kfree(ring[i]);
	}
	kfree(ring);
	}

	int srp_target_alloc(struct srp_target target, struct device dev,
	size_t nr, size_t iu_size)
	{
	int err;

	spin_lock_init(&target->lock);
	INIT_LIST_HEAD(&target->cmd_queue);

	target->dev = dev;
	dev_set_drvdata(target->dev, target);

	target->srp_iu_size = iu_size;
	target->rx_ring_size = nr;
	target->rx_ring = srp_ring_alloc(target->dev, nr, iu_size);
	if (!target->rx_ring)
	return -ENOMEM;
	err = srp_iu_pool_alloc(&target->iu_queue, nr, target->rx_ring);
	if (err)
	goto free_ring;

	return 0;

	free_ring:
	srp_ring_free(target->dev, target->rx_ring, nr, iu_size);
	return -ENOMEM;
	}
	EXPORT_SYMBOL_GPL(srp_target_alloc);

	void srp_target_free(struct srp_target *target)
	{
	srp_ring_free(target->dev, target->rx_ring, target->rx_ring_size,
	target->srp_iu_size);
	srp_iu_pool_free(&target->iu_queue);
	}
	EXPORT_SYMBOL_GPL(srp_target_free);

	struct iu_entry srp_iu_get(struct srp_target target)
	{
	struct iu_entry *iue = NULL;

	if (kfifo_out_locked(&target->iu_queue.queue, (void *) &iue,
	sizeof(void ), &target->iu_queue.lock) != sizeof(void )) {
	WARN_ONCE(1, "unexpected fifo state");
	return NULL;
	}
	if (!iue)
	return iue;
	iue->target = target;
	INIT_LIST_HEAD(&iue->ilist);
	iue->flags = 0;
	return iue;
	}
	EXPORT_SYMBOL_GPL(srp_iu_get);

	void srp_iu_put(struct iu_entry *iue)
	{
	kfifo_in_locked(&iue->target->iu_queue.queue, (void *) &iue,
	sizeof(void *), &iue->target->iu_queue.lock);
	}
	EXPORT_SYMBOL_GPL(srp_iu_put);

	static int srp_direct_data(struct scsi_cmnd sc, struct srp_direct_buf md,
	enum dma_data_direction dir, srp_rdma_t rdma_io,
	int dma_map, int ext_desc)
	{
	struct iu_entry *iue = NULL;
	struct scatterlist *sg = NULL;
	int err, nsg = 0, len;

	if (dma_map) {
	iue = (struct iu_entry *) sc->SCp.ptr;
	sg = scsi_sglist(sc);

	dprintk("%p %u %u %d\n", iue, scsi_bufflen(sc),
	md->len, scsi_sg_count(sc));

	nsg = dma_map_sg(iue->target->dev, sg, scsi_sg_count(sc),
	DMA_BIDIRECTIONAL);
	if (!nsg) {
	printk("fail to map %p %d\n", iue, scsi_sg_count(sc));
	return 0;
	}
	len = min(scsi_bufflen(sc), md->len);
	} else
	len = md->len;

	err = rdma_io(sc, sg, nsg, md, 1, dir, len);

	if (dma_map)
	dma_unmap_sg(iue->target->dev, sg, nsg, DMA_BIDIRECTIONAL);

	return err;
	}

	static int srp_indirect_data(struct scsi_cmnd sc, struct srp_cmd cmd,
	struct srp_indirect_buf *id,
	enum dma_data_direction dir, srp_rdma_t rdma_io,
	int dma_map, int ext_desc)
	{
	struct iu_entry *iue = NULL;
	struct srp_direct_buf *md = NULL;
	struct scatterlist dummy, *sg = NULL;
	dma_addr_t token = 0;
	int err = 0;
	int nmd, nsg = 0, len;

	if (dma_map \|\| ext_desc) {
	iue = (struct iu_entry *) sc->SCp.ptr;
	sg = scsi_sglist(sc);

	dprintk("%p %u %u %d %d\n",
	iue, scsi_bufflen(sc), id->len,
	cmd->data_in_desc_cnt, cmd->data_out_desc_cnt);
	}

	nmd = id->table_desc.len / sizeof(struct srp_direct_buf);

	if ((dir == DMA_FROM_DEVICE && nmd == cmd->data_in_desc_cnt) \|\|
	(dir == DMA_TO_DEVICE && nmd == cmd->data_out_desc_cnt)) {
	md = &id->desc_list[0];
	goto rdma;
	}

	if (ext_desc && dma_map) {
	md = dma_alloc_coherent(iue->target->dev, id->table_desc.len,
	&token, GFP_KERNEL);
	if (!md) {
	eprintk("Can't get dma memory %u\n", id->table_desc.len);
	return -ENOMEM;
	}

	sg_init_one(&dummy, md, id->table_desc.len);
	sg_dma_address(&dummy) = token;
	sg_dma_len(&dummy) = id->table_desc.len;
	err = rdma_io(sc, &dummy, 1, &id->table_desc, 1, DMA_TO_DEVICE,
	id->table_desc.len);
	if (err) {
	eprintk("Error copying indirect table %d\n", err);
	goto free_mem;
	}
	} else {
	eprintk("This command uses external indirect buffer\n");
	return -EINVAL;
	}

	rdma:
	if (dma_map) {
	nsg = dma_map_sg(iue->target->dev, sg, scsi_sg_count(sc),
	DMA_BIDIRECTIONAL);
	if (!nsg) {
	eprintk("fail to map %p %d\n", iue, scsi_sg_count(sc));
	err = -EIO;
	goto free_mem;
	}
	len = min(scsi_bufflen(sc), id->len);
	} else
	len = id->len;

	err = rdma_io(sc, sg, nsg, md, nmd, dir, len);

	if (dma_map)
	dma_unmap_sg(iue->target->dev, sg, nsg, DMA_BIDIRECTIONAL);

	free_mem:
	if (token && dma_map)
	dma_free_coherent(iue->target->dev, id->table_desc.len, md, token);

	return err;
	}

	static int data_out_desc_size(struct srp_cmd *cmd)
	{
	int size = 0;
	u8 fmt = cmd->buf_fmt >> 4;

	switch (fmt) {
	case SRP_NO_DATA_DESC:
	break;
	case SRP_DATA_DESC_DIRECT:
	size = sizeof(struct srp_direct_buf);
	break;
	case SRP_DATA_DESC_INDIRECT:
	size = sizeof(struct srp_indirect_buf) +
	sizeof(struct srp_direct_buf) * cmd->data_out_desc_cnt;
	break;
	default:
	eprintk("client error. Invalid data_out_format %x\n", fmt);
	break;
	}
	return size;
	}

	/*
	* TODO: this can be called multiple times for a single command if it
	* has very long data.
	*/
	int srp_transfer_data(struct scsi_cmnd sc, struct srp_cmd cmd,
	srp_rdma_t rdma_io, int dma_map, int ext_desc)
	{
	struct srp_direct_buf *md;
	struct srp_indirect_buf *id;
	enum dma_data_direction dir;
	int offset, err = 0;
	u8 format;

	offset = cmd->add_cdb_len * 4;

	dir = srp_cmd_direction(cmd);
	if (dir == DMA_FROM_DEVICE)
	offset += data_out_desc_size(cmd);

	if (dir == DMA_TO_DEVICE)
	format = cmd->buf_fmt >> 4;
	else
	format = cmd->buf_fmt & ((1U << 4) - 1);

	switch (format) {
	case SRP_NO_DATA_DESC:
	break;
	case SRP_DATA_DESC_DIRECT:
	md = (struct srp_direct_buf *)
	(cmd->add_data + offset);
	err = srp_direct_data(sc, md, dir, rdma_io, dma_map, ext_desc);
	break;
	case SRP_DATA_DESC_INDIRECT:
	id = (struct srp_indirect_buf *)
	(cmd->add_data + offset);
	err = srp_indirect_data(sc, cmd, id, dir, rdma_io, dma_map,
	ext_desc);
	break;
	default:
	eprintk("Unknown format %d %x\n", dir, format);
	err = -EINVAL;
	}

	return err;
	}
	EXPORT_SYMBOL_GPL(srp_transfer_data);

	static int vscsis_data_length(struct srp_cmd *cmd, enum dma_data_direction dir)
	{
	struct srp_direct_buf *md;
	struct srp_indirect_buf *id;
	int len = 0, offset = cmd->add_cdb_len * 4;
	u8 fmt;

	if (dir == DMA_TO_DEVICE)
	fmt = cmd->buf_fmt >> 4;
	else {
	fmt = cmd->buf_fmt & ((1U << 4) - 1);
	offset += data_out_desc_size(cmd);
	}

	switch (fmt) {
	case SRP_NO_DATA_DESC:
	break;
	case SRP_DATA_DESC_DIRECT:
	md = (struct srp_direct_buf *) (cmd->add_data + offset);
	len = md->len;
	break;
	case SRP_DATA_DESC_INDIRECT:
	id = (struct srp_indirect_buf *) (cmd->add_data + offset);
	len = id->len;
	break;
	default:
	eprintk("invalid data format %x\n", fmt);
	break;
	}
	return len;
	}

	int srp_cmd_queue(struct Scsi_Host shost, struct srp_cmd cmd, void *info,
	u64 itn_id, u64 addr)
	{
	enum dma_data_direction dir;
	struct scsi_cmnd *sc;
	int tag, len, err;

	switch (cmd->task_attr) {
	case SRP_SIMPLE_TASK:
	tag = MSG_SIMPLE_TAG;
	break;
	case SRP_ORDERED_TASK:
	tag = MSG_ORDERED_TAG;
	break;
	case SRP_HEAD_TASK:
	tag = MSG_HEAD_TAG;
	break;
	default:
	eprintk("Task attribute %d not supported\n", cmd->task_attr);
	tag = MSG_ORDERED_TAG;
	}

	dir = srp_cmd_direction(cmd);
	len = vscsis_data_length(cmd, dir);

	dprintk("%p %x %lx %d %d %d %llx\n", info, cmd->cdb[0],
	cmd->lun, dir, len, tag, (unsigned long long) cmd->tag);

	sc = scsi_host_get_command(shost, dir, GFP_KERNEL);
	if (!sc)
	return -ENOMEM;

	sc->SCp.ptr = info;
	memcpy(sc->cmnd, cmd->cdb, MAX_COMMAND_SIZE);
	sc->sdb.length = len;
	sc->sdb.table.sgl = (void *) (unsigned long) addr;
	sc->tag = tag;
	err = scsi_tgt_queue_command(sc, itn_id, (struct scsi_lun *)&cmd->lun,
	cmd->tag);
	if (err)
	scsi_host_put_command(shost, sc);

	return err;
	}
	EXPORT_SYMBOL_GPL(srp_cmd_queue);

	MODULE_DESCRIPTION("SCSI RDMA Protocol lib functions");
	MODULE_AUTHOR("FUJITA Tomonori");
	MODULE_LICENSE("GPL");