libsrp.c

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/*
 * SCSI RDMA Protocol lib functions
 *
 * Copyright (C) 2006 FUJITA Tomonori <[email protected]>
 *
 * 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/slab.h>
#include <linux/kfifo.h>
#include <linux/scatterlist.h>
#include <linux/dma-mapping.h>
#include <linux/module.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 & ~3;

    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 & ~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 = 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");