fc_libfc.c

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/*
 * Copyright(c) 2009 Intel Corporation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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.
 *
 * Maintained at www.Open-FCoE.org
 */

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/scatterlist.h>
#include <linux/crc32.h>
#include <linux/module.h>

#include <scsi/libfc.h>
#include <scsi/fc_encode.h>

#include "fc_libfc.h"

MODULE_AUTHOR("Open-FCoE.org");
MODULE_DESCRIPTION("libfc");
MODULE_LICENSE("GPL v2");

unsigned int fc_debug_logging;
module_param_named(debug_logging, fc_debug_logging, int, S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(debug_logging, "a bit mask of logging levels");

DEFINE_MUTEX(fc_prov_mutex);
static LIST_HEAD(fc_local_ports);
struct blocking_notifier_head fc_lport_notifier_head =
        BLOCKING_NOTIFIER_INIT(fc_lport_notifier_head);
EXPORT_SYMBOL(fc_lport_notifier_head);

/*
 * Providers which primarily send requests and PRLIs.
 */
struct fc4_prov *fc_active_prov[FC_FC4_PROV_SIZE] = {
    [0] = &fc_rport_t0_prov,
    [FC_TYPE_FCP] = &fc_rport_fcp_init,
};

/*
 * Providers which receive requests.
 */
struct fc4_prov *fc_passive_prov[FC_FC4_PROV_SIZE] = {
    [FC_TYPE_ELS] = &fc_lport_els_prov,
};

static int __init libfc_init(void)
{
    int rc = 0;

    rc = fc_setup_fcp();
    if (rc)
        return rc;

    rc = fc_setup_exch_mgr();
    if (rc)
        goto destroy_pkt_cache;

    rc = fc_setup_rport();
    if (rc)
        goto destroy_em;

    return rc;
destroy_em:
    fc_destroy_exch_mgr();
destroy_pkt_cache:
    fc_destroy_fcp();
    return rc;
}
module_init(libfc_init);

static void __exit libfc_exit(void)
{
    fc_destroy_fcp();
    fc_destroy_exch_mgr();
    fc_destroy_rport();
}
module_exit(libfc_exit);

u32 fc_copy_buffer_to_sglist(void *buf, size_t len,
                 struct scatterlist *sg,
                 u32 *nents, size_t *offset,
                 u32 *crc)
{
    size_t remaining = len;
    u32 copy_len = 0;

    while (remaining > 0 && sg) {
        size_t off, sg_bytes;
        void *page_addr;

        if (*offset >= sg->length) {
            /*
             * Check for end and drop resources
             * from the last iteration.
             */
            if (!(*nents))
                break;
            --(*nents);
            *offset -= sg->length;
            sg = sg_next(sg);
            continue;
        }
        sg_bytes = min(remaining, sg->length - *offset);

        /*
         * The scatterlist item may be bigger than PAGE_SIZE,
         * but we are limited to mapping PAGE_SIZE at a time.
         */
        off = *offset + sg->offset;
        sg_bytes = min(sg_bytes,
                   (size_t)(PAGE_SIZE - (off & ~PAGE_MASK)));
        page_addr = kmap_atomic(sg_page(sg) + (off >> PAGE_SHIFT));
        if (crc)
            *crc = crc32(*crc, buf, sg_bytes);
        memcpy((char *)page_addr + (off & ~PAGE_MASK), buf, sg_bytes);
        kunmap_atomic(page_addr);
        buf += sg_bytes;
        *offset += sg_bytes;
        remaining -= sg_bytes;
        copy_len += sg_bytes;
    }
    return copy_len;
}

void fc_fill_hdr(struct fc_frame *fp, const struct fc_frame *in_fp,
         enum fc_rctl r_ctl, u32 f_ctl, u16 seq_cnt, u32 parm_offset)
{
    struct fc_frame_header *fh;
    struct fc_frame_header *in_fh;
    struct fc_seq *sp;
    u32 fill;

    fh = __fc_frame_header_get(fp);
    in_fh = __fc_frame_header_get(in_fp);

    if (f_ctl & FC_FC_END_SEQ) {
        fill = -fr_len(fp) & 3;
        if (fill) {
            /* TODO, this may be a problem with fragmented skb */
            memset(skb_put(fp_skb(fp), fill), 0, fill);
            f_ctl |= fill;
        }
        fr_eof(fp) = FC_EOF_T;
    } else {
        WARN_ON(fr_len(fp) % 4 != 0);   /* no pad to non last frame */
        fr_eof(fp) = FC_EOF_N;
    }

    fh->fh_r_ctl = r_ctl;
    memcpy(fh->fh_d_id, in_fh->fh_s_id, sizeof(fh->fh_d_id));
    memcpy(fh->fh_s_id, in_fh->fh_d_id, sizeof(fh->fh_s_id));
    fh->fh_type = in_fh->fh_type;
    hton24(fh->fh_f_ctl, f_ctl);
    fh->fh_ox_id = in_fh->fh_ox_id;
    fh->fh_rx_id = in_fh->fh_rx_id;
    fh->fh_cs_ctl = 0;
    fh->fh_df_ctl = 0;
    fh->fh_parm_offset = htonl(parm_offset);

    sp = fr_seq(in_fp);
    if (sp) {
        fr_seq(fp) = sp;
        fh->fh_seq_id = sp->id;
        seq_cnt = sp->cnt;
    } else {
        fh->fh_seq_id = 0;
    }
    fh->fh_seq_cnt = ntohs(seq_cnt);
    fr_sof(fp) = seq_cnt ? FC_SOF_N3 : FC_SOF_I3;
    fr_encaps(fp) = fr_encaps(in_fp);
}
EXPORT_SYMBOL(fc_fill_hdr);

void fc_fill_reply_hdr(struct fc_frame *fp, const struct fc_frame *in_fp,
               enum fc_rctl r_ctl, u32 parm_offset)
{
    struct fc_seq *sp;

    sp = fr_seq(in_fp);
    if (sp)
        fr_seq(fp) = fr_dev(in_fp)->tt.seq_start_next(sp);
    fc_fill_hdr(fp, in_fp, r_ctl, FC_FCTL_RESP, 0, parm_offset);
}
EXPORT_SYMBOL(fc_fill_reply_hdr);

void fc_fc4_conf_lport_params(struct fc_lport *lport, enum fc_fh_type type)
{
    struct fc4_prov *prov_entry;
    BUG_ON(type >= FC_FC4_PROV_SIZE);
    BUG_ON(!lport);
    prov_entry = fc_passive_prov[type];
    if (type == FC_TYPE_FCP) {
        if (prov_entry && prov_entry->recv)
            lport->service_params |= FCP_SPPF_TARG_FCN;
    }
}

void fc_lport_iterate(void (*notify)(struct fc_lport *, void *), void *arg)
{
    struct fc_lport *lport;

    mutex_lock(&fc_prov_mutex);
    list_for_each_entry(lport, &fc_local_ports, lport_list)
        notify(lport, arg);
    mutex_unlock(&fc_prov_mutex);
}
EXPORT_SYMBOL(fc_lport_iterate);

int fc_fc4_register_provider(enum fc_fh_type type, struct fc4_prov *prov)
{
    struct fc4_prov **prov_entry;
    int ret = 0;

    if (type >= FC_FC4_PROV_SIZE)
        return -EINVAL;
    mutex_lock(&fc_prov_mutex);
    prov_entry = (prov->recv ? fc_passive_prov : fc_active_prov) + type;
    if (*prov_entry)
        ret = -EBUSY;
    else
        *prov_entry = prov;
    mutex_unlock(&fc_prov_mutex);
    return ret;
}
EXPORT_SYMBOL(fc_fc4_register_provider);

void fc_fc4_deregister_provider(enum fc_fh_type type, struct fc4_prov *prov)
{
    BUG_ON(type >= FC_FC4_PROV_SIZE);
    mutex_lock(&fc_prov_mutex);
    if (prov->recv)
        rcu_assign_pointer(fc_passive_prov[type], NULL);
    else
        rcu_assign_pointer(fc_active_prov[type], NULL);
    mutex_unlock(&fc_prov_mutex);
    synchronize_rcu();
}
EXPORT_SYMBOL(fc_fc4_deregister_provider);

void fc_fc4_add_lport(struct fc_lport *lport)
{
    mutex_lock(&fc_prov_mutex);
    list_add_tail(&lport->lport_list, &fc_local_ports);
    blocking_notifier_call_chain(&fc_lport_notifier_head,
                     FC_LPORT_EV_ADD, lport);
    mutex_unlock(&fc_prov_mutex);
}

void fc_fc4_del_lport(struct fc_lport *lport)
{
    mutex_lock(&fc_prov_mutex);
    list_del(&lport->lport_list);
    blocking_notifier_call_chain(&fc_lport_notifier_head,
                     FC_LPORT_EV_DEL, lport);
    mutex_unlock(&fc_prov_mutex);
}