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");