linux/drivers/scsi/ibmvscsi_tgt/libsrp.c

428 lines
10 KiB
C

/*******************************************************************************
* 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");