scsi_transport_srp.c

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/*
 * SCSI RDMA (SRP) transport class
 *
 * Copyright (C) 2007 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, version 2 of the
 * License.
 *
 * 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/init.h>
#include <linux/module.h>
#include <linux/jiffies.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/string.h>

#include <scsi/scsi.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_transport.h>
#include <scsi/scsi_transport_srp.h>
#include "scsi_transport_srp_internal.h"

struct srp_host_attrs {
    atomic_t next_port_id;
};
#define to_srp_host_attrs(host) ((struct srp_host_attrs *)(host)->shost_data)

#define SRP_HOST_ATTRS 0
#define SRP_RPORT_ATTRS 2

struct srp_internal {
    struct scsi_transport_template t;
    struct srp_function_template *f;

    struct device_attribute *host_attrs[SRP_HOST_ATTRS + 1];

    struct device_attribute *rport_attrs[SRP_RPORT_ATTRS + 1];
    struct device_attribute private_rport_attrs[SRP_RPORT_ATTRS];
    struct transport_container rport_attr_cont;
};

#define to_srp_internal(tmpl) container_of(tmpl, struct srp_internal, t)

#define dev_to_rport(d) container_of(d, struct srp_rport, dev)
#define transport_class_to_srp_rport(dev) dev_to_rport((dev)->parent)

static int srp_host_setup(struct transport_container *tc, struct device *dev,
              struct device *cdev)
{
    struct Scsi_Host *shost = dev_to_shost(dev);
    struct srp_host_attrs *srp_host = to_srp_host_attrs(shost);

    atomic_set(&srp_host->next_port_id, 0);
    return 0;
}

static DECLARE_TRANSPORT_CLASS(srp_host_class, "srp_host", srp_host_setup,
                   NULL, NULL);

static DECLARE_TRANSPORT_CLASS(srp_rport_class, "srp_remote_ports",
                   NULL, NULL, NULL);

#define SETUP_TEMPLATE(attrb, field, perm, test, ro_test, ro_perm)  \
    i->private_##attrb[count] = dev_attr_##field;       \
    i->private_##attrb[count].attr.mode = perm;         \
    if (ro_test) {                          \
        i->private_##attrb[count].attr.mode = ro_perm;      \
        i->private_##attrb[count].store = NULL;         \
    }                               \
    i->attrb[count] = &i->private_##attrb[count];           \
    if (test)                           \
        count++

#define SETUP_RPORT_ATTRIBUTE_RD(field)                 \
    SETUP_TEMPLATE(rport_attrs, field, S_IRUGO, 1, 0, 0)

#define SETUP_RPORT_ATTRIBUTE_RW(field)                 \
    SETUP_TEMPLATE(rport_attrs, field, S_IRUGO | S_IWUSR,       \
               1, 1, S_IRUGO)

#define SRP_PID(p) \
    (p)->port_id[0], (p)->port_id[1], (p)->port_id[2], (p)->port_id[3], \
    (p)->port_id[4], (p)->port_id[5], (p)->port_id[6], (p)->port_id[7], \
    (p)->port_id[8], (p)->port_id[9], (p)->port_id[10], (p)->port_id[11], \
    (p)->port_id[12], (p)->port_id[13], (p)->port_id[14], (p)->port_id[15]

#define SRP_PID_FMT "%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:" \
    "%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x"

static ssize_t
show_srp_rport_id(struct device *dev, struct device_attribute *attr,
          char *buf)
{
    struct srp_rport *rport = transport_class_to_srp_rport(dev);
    return sprintf(buf, SRP_PID_FMT "\n", SRP_PID(rport));
}

static DEVICE_ATTR(port_id, S_IRUGO, show_srp_rport_id, NULL);

static const struct {
    u32 value;
    char *name;
} srp_rport_role_names[] = {
    {SRP_RPORT_ROLE_INITIATOR, "SRP Initiator"},
    {SRP_RPORT_ROLE_TARGET, "SRP Target"},
};

static ssize_t
show_srp_rport_roles(struct device *dev, struct device_attribute *attr,
             char *buf)
{
    struct srp_rport *rport = transport_class_to_srp_rport(dev);
    int i;
    char *name = NULL;

    for (i = 0; i < ARRAY_SIZE(srp_rport_role_names); i++)
        if (srp_rport_role_names[i].value == rport->roles) {
            name = srp_rport_role_names[i].name;
            break;
        }
    return sprintf(buf, "%s\n", name ? : "unknown");
}

static DEVICE_ATTR(roles, S_IRUGO, show_srp_rport_roles, NULL);

static void srp_rport_release(struct device *dev)
{
    struct srp_rport *rport = dev_to_rport(dev);

    put_device(dev->parent);
    kfree(rport);
}

static int scsi_is_srp_rport(const struct device *dev)
{
    return dev->release == srp_rport_release;
}

static int srp_rport_match(struct attribute_container *cont,
               struct device *dev)
{
    struct Scsi_Host *shost;
    struct srp_internal *i;

    if (!scsi_is_srp_rport(dev))
        return 0;

    shost = dev_to_shost(dev->parent);
    if (!shost->transportt)
        return 0;
    if (shost->transportt->host_attrs.ac.class != &srp_host_class.class)
        return 0;

    i = to_srp_internal(shost->transportt);
    return &i->rport_attr_cont.ac == cont;
}

static int srp_host_match(struct attribute_container *cont, struct device *dev)
{
    struct Scsi_Host *shost;
    struct srp_internal *i;

    if (!scsi_is_host_device(dev))
        return 0;

    shost = dev_to_shost(dev);
    if (!shost->transportt)
        return 0;
    if (shost->transportt->host_attrs.ac.class != &srp_host_class.class)
        return 0;

    i = to_srp_internal(shost->transportt);
    return &i->t.host_attrs.ac == cont;
}

struct srp_rport *srp_rport_add(struct Scsi_Host *shost,
                struct srp_rport_identifiers *ids)
{
    struct srp_rport *rport;
    struct device *parent = &shost->shost_gendev;
    int id, ret;

    rport = kzalloc(sizeof(*rport), GFP_KERNEL);
    if (!rport)
        return ERR_PTR(-ENOMEM);

    device_initialize(&rport->dev);

    rport->dev.parent = get_device(parent);
    rport->dev.release = srp_rport_release;

    memcpy(rport->port_id, ids->port_id, sizeof(rport->port_id));
    rport->roles = ids->roles;

    id = atomic_inc_return(&to_srp_host_attrs(shost)->next_port_id);
    dev_set_name(&rport->dev, "port-%d:%d", shost->host_no, id);

    transport_setup_device(&rport->dev);

    ret = device_add(&rport->dev);
    if (ret) {
        transport_destroy_device(&rport->dev);
        put_device(&rport->dev);
        return ERR_PTR(ret);
    }

    if (shost->active_mode & MODE_TARGET &&
        ids->roles == SRP_RPORT_ROLE_INITIATOR) {
        ret = srp_tgt_it_nexus_create(shost, (unsigned long)rport,
                          rport->port_id);
        if (ret) {
            device_del(&rport->dev);
            transport_destroy_device(&rport->dev);
            put_device(&rport->dev);
            return ERR_PTR(ret);
        }
    }

    transport_add_device(&rport->dev);
    transport_configure_device(&rport->dev);

    return rport;
}
EXPORT_SYMBOL_GPL(srp_rport_add);

void srp_rport_del(struct srp_rport *rport)
{
    struct device *dev = &rport->dev;
    struct Scsi_Host *shost = dev_to_shost(dev->parent);

    if (shost->active_mode & MODE_TARGET &&
        rport->roles == SRP_RPORT_ROLE_INITIATOR)
        srp_tgt_it_nexus_destroy(shost, (unsigned long)rport);

    transport_remove_device(dev);
    device_del(dev);
    transport_destroy_device(dev);
    put_device(dev);
}
EXPORT_SYMBOL_GPL(srp_rport_del);

static int do_srp_rport_del(struct device *dev, void *data)
{
    if (scsi_is_srp_rport(dev))
        srp_rport_del(dev_to_rport(dev));
    return 0;
}

void srp_remove_host(struct Scsi_Host *shost)
{
    device_for_each_child(&shost->shost_gendev, NULL, do_srp_rport_del);
}
EXPORT_SYMBOL_GPL(srp_remove_host);

static int srp_tsk_mgmt_response(struct Scsi_Host *shost, u64 nexus, u64 tm_id,
                 int result)
{
    struct srp_internal *i = to_srp_internal(shost->transportt);
    return i->f->tsk_mgmt_response(shost, nexus, tm_id, result);
}

static int srp_it_nexus_response(struct Scsi_Host *shost, u64 nexus, int result)
{
    struct srp_internal *i = to_srp_internal(shost->transportt);
    return i->f->it_nexus_response(shost, nexus, result);
}

struct scsi_transport_template *
srp_attach_transport(struct srp_function_template *ft)
{
    int count;
    struct srp_internal *i;

    i = kzalloc(sizeof(*i), GFP_KERNEL);
    if (!i)
        return NULL;

    i->t.tsk_mgmt_response = srp_tsk_mgmt_response;
    i->t.it_nexus_response = srp_it_nexus_response;

    i->t.host_size = sizeof(struct srp_host_attrs);
    i->t.host_attrs.ac.attrs = &i->host_attrs[0];
    i->t.host_attrs.ac.class = &srp_host_class.class;
    i->t.host_attrs.ac.match = srp_host_match;
    i->host_attrs[0] = NULL;
    transport_container_register(&i->t.host_attrs);

    i->rport_attr_cont.ac.attrs = &i->rport_attrs[0];
    i->rport_attr_cont.ac.class = &srp_rport_class.class;
    i->rport_attr_cont.ac.match = srp_rport_match;
    transport_container_register(&i->rport_attr_cont);

    count = 0;
    SETUP_RPORT_ATTRIBUTE_RD(port_id);
    SETUP_RPORT_ATTRIBUTE_RD(roles);
    i->rport_attrs[count] = NULL;

    i->f = ft;

    return &i->t;
}
EXPORT_SYMBOL_GPL(srp_attach_transport);

void srp_release_transport(struct scsi_transport_template *t)
{
    struct srp_internal *i = to_srp_internal(t);

    transport_container_unregister(&i->t.host_attrs);
    transport_container_unregister(&i->rport_attr_cont);

    kfree(i);
}
EXPORT_SYMBOL_GPL(srp_release_transport);

static __init int srp_transport_init(void)
{
    int ret;

    ret = transport_class_register(&srp_host_class);
    if (ret)
        return ret;
    ret = transport_class_register(&srp_rport_class);
    if (ret)
        goto unregister_host_class;

    return 0;
unregister_host_class:
    transport_class_unregister(&srp_host_class);
    return ret;
}

static void __exit srp_transport_exit(void)
{
    transport_class_unregister(&srp_host_class);
    transport_class_unregister(&srp_rport_class);
}

MODULE_AUTHOR("FUJITA Tomonori");
MODULE_DESCRIPTION("SRP Transport Attributes");
MODULE_LICENSE("GPL");

module_init(srp_transport_init);
module_exit(srp_transport_exit);