ibmvscsis: Initial commit of IBM VSCSI Tgt Driver

This driver is a pick up of the old IBM VIO scsi Target Driver
that was started by Nick and Fujita 2-4 years ago.
http://comments.gmane.org/gmane.linux.scsi/90119

The driver provides a virtual SCSI device on IBM Power Servers.

This patch contains the fifth version for an initial merge of the
tcm ibmvscsis driver. More information on this driver and config
can be found:

https://github.com/powervm/ibmvscsis/wiki/Configuration
http://www.linux-iscsi.org/wiki/IBM_vSCSI

(Drop extra libsrp review breakage + Fix kconfig typo - nab)

Signed-off-by: Steven Royer <seroyer@linux.vnet.ibm.com>
Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Signed-off-by: Michael Cyr <mikecyr@linux.vnet.ibm.com>
Signed-off-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Cc: FUJITA Tomonori <tomof@acm.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 427 insertions, 0 deletions

diff --git a/drivers/scsi/ibmvscsi_tgt/libsrp.c b/drivers/scsi/ibmvscsi_tgt/libsrp.c
new file mode 100644
index 000000000000..5a4cc28ca5ff
--- /dev/null
+++ b/drivers/scsi/ibmvscsi_tgt/libsrp.c
@@ -0,0 +1,427 @@
+/*******************************************************************************
+ * SCSI RDMA Protocol lib functions
+ *
+ * Copyright (C) 2006 FUJITA Tomonori <tomof@acm.org>
+ * Copyright (C) 2016 Bryant G. Ly <bryantly@linux.vnet.ibm.com> IBM Corp.
+ *
+ * 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.
+ *
+ ***********************************************************************/
+
+#define pr_fmt(fmt)	"libsrp: " fmt
+
+#include <linux/printk.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/kfifo.h>
+#include <linux/scatterlist.h>
+#include <linux/dma-mapping.h>
+#include <linux/module.h>
+#include <scsi/srp.h>
+#include <target/target_core_base.h>
+#include "libsrp.h"
+#include "ibmvscsi_tgt.h"
+
+static int srp_iu_pool_alloc(struct srp_queue *q, size_t max,
+			     struct srp_buf **ring)
+{
+	struct iu_entry *iue;
+	int i;
+
+	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;
+
+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)
+{
+	struct srp_buf **ring;
+	int i;
+
+	ring = kcalloc(max, sizeof(struct srp_buf *), GFP_KERNEL);
+	if (!ring)
+		return NULL;
+
+	for (i = 0; i < max; i++) {
+		ring[i] = kzalloc(sizeof(*ring[i]), 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);
+
+	target->dev = dev;
+
+	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;
+
+	dev_set_drvdata(target->dev, target);
+	return 0;
+
+free_ring:
+	srp_ring_free(target->dev, target->rx_ring, nr, iu_size);
+	return -ENOMEM;
+}
+
+void srp_target_free(struct srp_target *target)
+{
+	dev_set_drvdata(target->dev, NULL);
+	srp_ring_free(target->dev, target->rx_ring, target->rx_ring_size,
+		      target->srp_iu_size);
+	srp_iu_pool_free(&target->iu_queue);
+}
+
+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;
+	iue->flags = 0;
+	return iue;
+}
+
+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);
+}
+
+static int srp_direct_data(struct ibmvscsis_cmd *cmd, 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 = cmd->iue;
+		sg = cmd->se_cmd.t_data_sg;
+		nsg = dma_map_sg(iue->target->dev, sg, cmd->se_cmd.t_data_nents,
+				 DMA_BIDIRECTIONAL);
+		if (!nsg) {
+			pr_err("fail to map %p %d\n", iue,
+			       cmd->se_cmd.t_data_nents);
+			return 0;
+		}
+		len = min(cmd->se_cmd.data_length, be32_to_cpu(md->len));
+	} else {
+		len = be32_to_cpu(md->len);
+	}
+
+	err = rdma_io(cmd, 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 ibmvscsis_cmd *cmd, struct srp_cmd *srp_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 = cmd->iue;
+		sg = cmd->se_cmd.t_data_sg;
+	}
+
+	nmd = be32_to_cpu(id->table_desc.len) / sizeof(struct srp_direct_buf);
+
+	if ((dir == DMA_FROM_DEVICE && nmd == srp_cmd->data_in_desc_cnt) ||
+	    (dir == DMA_TO_DEVICE && nmd == srp_cmd->data_out_desc_cnt)) {
+		md = &id->desc_list[0];
+		goto rdma;
+	}
+
+	if (ext_desc && dma_map) {
+		md = dma_alloc_coherent(iue->target->dev,
+					be32_to_cpu(id->table_desc.len),
+					&token, GFP_KERNEL);
+		if (!md) {
+			pr_err("Can't get dma memory %u\n",
+			       be32_to_cpu(id->table_desc.len));
+			return -ENOMEM;
+		}
+
+		sg_init_one(&dummy, md, be32_to_cpu(id->table_desc.len));
+		sg_dma_address(&dummy) = token;
+		sg_dma_len(&dummy) = be32_to_cpu(id->table_desc.len);
+		err = rdma_io(cmd, &dummy, 1, &id->table_desc, 1, DMA_TO_DEVICE,
+			      be32_to_cpu(id->table_desc.len));
+		if (err) {
+			pr_err("Error copying indirect table %d\n", err);
+			goto free_mem;
+		}
+	} else {
+		pr_err("This command uses external indirect buffer\n");
+		return -EINVAL;
+	}
+
+rdma:
+	if (dma_map) {
+		nsg = dma_map_sg(iue->target->dev, sg, cmd->se_cmd.t_data_nents,
+				 DMA_BIDIRECTIONAL);
+		if (!nsg) {
+			pr_err("fail to map %p %d\n", iue,
+			       cmd->se_cmd.t_data_nents);
+			err = -EIO;
+			goto free_mem;
+		}
+		len = min(cmd->se_cmd.data_length, be32_to_cpu(id->len));
+	} else {
+		len = be32_to_cpu(id->len);
+	}
+
+	err = rdma_io(cmd, 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,
+				  be32_to_cpu(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:
+		pr_err("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 ibmvscsis_cmd *cmd, struct srp_cmd *srp_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;
+
+	if (!cmd->se_cmd.t_data_nents)
+		return 0;
+
+	offset = srp_cmd->add_cdb_len & ~3;
+
+	dir = srp_cmd_direction(srp_cmd);
+	if (dir == DMA_FROM_DEVICE)
+		offset += data_out_desc_size(srp_cmd);
+
+	if (dir == DMA_TO_DEVICE)
+		format = srp_cmd->buf_fmt >> 4;
+	else
+		format = srp_cmd->buf_fmt & ((1U << 4) - 1);
+
+	switch (format) {
+	case SRP_NO_DATA_DESC:
+		break;
+	case SRP_DATA_DESC_DIRECT:
+		md = (struct srp_direct_buf *)(srp_cmd->add_data + offset);
+		err = srp_direct_data(cmd, md, dir, rdma_io, dma_map, ext_desc);
+		break;
+	case SRP_DATA_DESC_INDIRECT:
+		id = (struct srp_indirect_buf *)(srp_cmd->add_data + offset);
+		err = srp_indirect_data(cmd, srp_cmd, id, dir, rdma_io, dma_map,
+					ext_desc);
+		break;
+	default:
+		pr_err("Unknown format %d %x\n", dir, format);
+		err = -EINVAL;
+	}
+
+	return err;
+}
+
+u64 srp_data_length(struct srp_cmd *cmd, enum dma_data_direction dir)
+{
+	struct srp_direct_buf *md;
+	struct srp_indirect_buf *id;
+	u64 len = 0;
+	uint offset = cmd->add_cdb_len & ~3;
+	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 = be32_to_cpu(md->len);
+		break;
+	case SRP_DATA_DESC_INDIRECT:
+		id = (struct srp_indirect_buf *)(cmd->add_data + offset);
+		len = be32_to_cpu(id->len);
+		break;
+	default:
+		pr_err("invalid data format %x\n", fmt);
+		break;
+	}
+	return len;
+}
+
+int srp_get_desc_table(struct srp_cmd *srp_cmd, enum dma_data_direction *dir,
+		       u64 *data_len)
+{
+	struct srp_indirect_buf *idb;
+	struct srp_direct_buf *db;
+	uint add_cdb_offset;
+	int rc;
+
+	/*
+	 * The pointer computations below will only be compiled correctly
+	 * if srp_cmd::add_data is declared as s8*, u8*, s8[] or u8[], so check
+	 * whether srp_cmd::add_data has been declared as a byte pointer.
+	 */
+	BUILD_BUG_ON(!__same_type(srp_cmd->add_data[0], (s8)0)
+		     && !__same_type(srp_cmd->add_data[0], (u8)0));
+
+	BUG_ON(!dir);
+	BUG_ON(!data_len);
+
+	rc = 0;
+	*data_len = 0;
+
+	*dir = DMA_NONE;
+
+	if (srp_cmd->buf_fmt & 0xf)
+		*dir = DMA_FROM_DEVICE;
+	else if (srp_cmd->buf_fmt >> 4)
+		*dir = DMA_TO_DEVICE;
+
+	add_cdb_offset = srp_cmd->add_cdb_len & ~3;
+	if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_DIRECT) ||
+	    ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_DIRECT)) {
+		db = (struct srp_direct_buf *)(srp_cmd->add_data
+					       + add_cdb_offset);
+		*data_len = be32_to_cpu(db->len);
+	} else if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_INDIRECT) ||
+		   ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_INDIRECT)) {
+		idb = (struct srp_indirect_buf *)(srp_cmd->add_data
+						  + add_cdb_offset);
+
+		*data_len = be32_to_cpu(idb->len);
+	}
+	return rc;
+}
+
+MODULE_DESCRIPTION("SCSI RDMA Protocol lib functions");
+MODULE_AUTHOR("FUJITA Tomonori");
+MODULE_LICENSE("GPL");