linux/drivers/scsi/libfc/fc_libfc.c
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   1/*
   2 * Copyright(c) 2009 Intel Corporation. All rights reserved.
   3 *
   4 * This program is free software; you can redistribute it and/or modify it
   5 * under the terms and conditions of the GNU General Public License,
   6 * version 2, as published by the Free Software Foundation.
   7 *
   8 * This program is distributed in the hope it will be useful, but WITHOUT
   9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11 * more details.
  12 *
  13 * You should have received a copy of the GNU General Public License along with
  14 * this program; if not, write to the Free Software Foundation, Inc.,
  15 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  16 *
  17 * Maintained at www.Open-FCoE.org
  18 */
  19
  20#include <linux/kernel.h>
  21#include <linux/types.h>
  22#include <linux/scatterlist.h>
  23#include <linux/crc32.h>
  24#include <linux/module.h>
  25
  26#include <scsi/libfc.h>
  27#include <scsi/fc_encode.h>
  28
  29#include "fc_libfc.h"
  30
  31MODULE_AUTHOR("Open-FCoE.org");
  32MODULE_DESCRIPTION("libfc");
  33MODULE_LICENSE("GPL v2");
  34
  35unsigned int fc_debug_logging;
  36module_param_named(debug_logging, fc_debug_logging, int, S_IRUGO|S_IWUSR);
  37MODULE_PARM_DESC(debug_logging, "a bit mask of logging levels");
  38
  39DEFINE_MUTEX(fc_prov_mutex);
  40static LIST_HEAD(fc_local_ports);
  41struct blocking_notifier_head fc_lport_notifier_head =
  42                BLOCKING_NOTIFIER_INIT(fc_lport_notifier_head);
  43EXPORT_SYMBOL(fc_lport_notifier_head);
  44
  45/*
  46 * Providers which primarily send requests and PRLIs.
  47 */
  48struct fc4_prov *fc_active_prov[FC_FC4_PROV_SIZE] = {
  49        [0] = &fc_rport_t0_prov,
  50        [FC_TYPE_FCP] = &fc_rport_fcp_init,
  51};
  52
  53/*
  54 * Providers which receive requests.
  55 */
  56struct fc4_prov *fc_passive_prov[FC_FC4_PROV_SIZE] = {
  57        [FC_TYPE_ELS] = &fc_lport_els_prov,
  58};
  59
  60/**
  61 * libfc_init() - Initialize libfc.ko
  62 */
  63static int __init libfc_init(void)
  64{
  65        int rc = 0;
  66
  67        rc = fc_setup_fcp();
  68        if (rc)
  69                return rc;
  70
  71        rc = fc_setup_exch_mgr();
  72        if (rc)
  73                goto destroy_pkt_cache;
  74
  75        rc = fc_setup_rport();
  76        if (rc)
  77                goto destroy_em;
  78
  79        return rc;
  80destroy_em:
  81        fc_destroy_exch_mgr();
  82destroy_pkt_cache:
  83        fc_destroy_fcp();
  84        return rc;
  85}
  86module_init(libfc_init);
  87
  88/**
  89 * libfc_exit() - Tear down libfc.ko
  90 */
  91static void __exit libfc_exit(void)
  92{
  93        fc_destroy_fcp();
  94        fc_destroy_exch_mgr();
  95        fc_destroy_rport();
  96}
  97module_exit(libfc_exit);
  98
  99/**
 100 * fc_copy_buffer_to_sglist() - This routine copies the data of a buffer
 101 *                              into a scatter-gather list (SG list).
 102 *
 103 * @buf: pointer to the data buffer.
 104 * @len: the byte-length of the data buffer.
 105 * @sg: pointer to the pointer of the SG list.
 106 * @nents: pointer to the remaining number of entries in the SG list.
 107 * @offset: pointer to the current offset in the SG list.
 108 * @crc: pointer to the 32-bit crc value.
 109 *       If crc is NULL, CRC is not calculated.
 110 */
 111u32 fc_copy_buffer_to_sglist(void *buf, size_t len,
 112                             struct scatterlist *sg,
 113                             u32 *nents, size_t *offset,
 114                             u32 *crc)
 115{
 116        size_t remaining = len;
 117        u32 copy_len = 0;
 118
 119        while (remaining > 0 && sg) {
 120                size_t off, sg_bytes;
 121                void *page_addr;
 122
 123                if (*offset >= sg->length) {
 124                        /*
 125                         * Check for end and drop resources
 126                         * from the last iteration.
 127                         */
 128                        if (!(*nents))
 129                                break;
 130                        --(*nents);
 131                        *offset -= sg->length;
 132                        sg = sg_next(sg);
 133                        continue;
 134                }
 135                sg_bytes = min(remaining, sg->length - *offset);
 136
 137                /*
 138                 * The scatterlist item may be bigger than PAGE_SIZE,
 139                 * but we are limited to mapping PAGE_SIZE at a time.
 140                 */
 141                off = *offset + sg->offset;
 142                sg_bytes = min(sg_bytes,
 143                               (size_t)(PAGE_SIZE - (off & ~PAGE_MASK)));
 144                page_addr = kmap_atomic(sg_page(sg) + (off >> PAGE_SHIFT));
 145                if (crc)
 146                        *crc = crc32(*crc, buf, sg_bytes);
 147                memcpy((char *)page_addr + (off & ~PAGE_MASK), buf, sg_bytes);
 148                kunmap_atomic(page_addr);
 149                buf += sg_bytes;
 150                *offset += sg_bytes;
 151                remaining -= sg_bytes;
 152                copy_len += sg_bytes;
 153        }
 154        return copy_len;
 155}
 156
 157/**
 158 * fc_fill_hdr() -  fill FC header fields based on request
 159 * @fp: reply frame containing header to be filled in
 160 * @in_fp: request frame containing header to use in filling in reply
 161 * @r_ctl: R_CTL value for header
 162 * @f_ctl: F_CTL value for header, with 0 pad
 163 * @seq_cnt: sequence count for the header, ignored if frame has a sequence
 164 * @parm_offset: parameter / offset value
 165 */
 166void fc_fill_hdr(struct fc_frame *fp, const struct fc_frame *in_fp,
 167                 enum fc_rctl r_ctl, u32 f_ctl, u16 seq_cnt, u32 parm_offset)
 168{
 169        struct fc_frame_header *fh;
 170        struct fc_frame_header *in_fh;
 171        struct fc_seq *sp;
 172        u32 fill;
 173
 174        fh = __fc_frame_header_get(fp);
 175        in_fh = __fc_frame_header_get(in_fp);
 176
 177        if (f_ctl & FC_FC_END_SEQ) {
 178                fill = -fr_len(fp) & 3;
 179                if (fill) {
 180                        /* TODO, this may be a problem with fragmented skb */
 181                        skb_put_zero(fp_skb(fp), fill);
 182                        f_ctl |= fill;
 183                }
 184                fr_eof(fp) = FC_EOF_T;
 185        } else {
 186                WARN_ON(fr_len(fp) % 4 != 0);   /* no pad to non last frame */
 187                fr_eof(fp) = FC_EOF_N;
 188        }
 189
 190        fh->fh_r_ctl = r_ctl;
 191        memcpy(fh->fh_d_id, in_fh->fh_s_id, sizeof(fh->fh_d_id));
 192        memcpy(fh->fh_s_id, in_fh->fh_d_id, sizeof(fh->fh_s_id));
 193        fh->fh_type = in_fh->fh_type;
 194        hton24(fh->fh_f_ctl, f_ctl);
 195        fh->fh_ox_id = in_fh->fh_ox_id;
 196        fh->fh_rx_id = in_fh->fh_rx_id;
 197        fh->fh_cs_ctl = 0;
 198        fh->fh_df_ctl = 0;
 199        fh->fh_parm_offset = htonl(parm_offset);
 200
 201        sp = fr_seq(in_fp);
 202        if (sp) {
 203                fr_seq(fp) = sp;
 204                fh->fh_seq_id = sp->id;
 205                seq_cnt = sp->cnt;
 206        } else {
 207                fh->fh_seq_id = 0;
 208        }
 209        fh->fh_seq_cnt = ntohs(seq_cnt);
 210        fr_sof(fp) = seq_cnt ? FC_SOF_N3 : FC_SOF_I3;
 211        fr_encaps(fp) = fr_encaps(in_fp);
 212}
 213EXPORT_SYMBOL(fc_fill_hdr);
 214
 215/**
 216 * fc_fill_reply_hdr() -  fill FC reply header fields based on request
 217 * @fp: reply frame containing header to be filled in
 218 * @in_fp: request frame containing header to use in filling in reply
 219 * @r_ctl: R_CTL value for reply
 220 * @parm_offset: parameter / offset value
 221 */
 222void fc_fill_reply_hdr(struct fc_frame *fp, const struct fc_frame *in_fp,
 223                       enum fc_rctl r_ctl, u32 parm_offset)
 224{
 225        struct fc_seq *sp;
 226
 227        sp = fr_seq(in_fp);
 228        if (sp)
 229                fr_seq(fp) = fc_seq_start_next(sp);
 230        fc_fill_hdr(fp, in_fp, r_ctl, FC_FCTL_RESP, 0, parm_offset);
 231}
 232EXPORT_SYMBOL(fc_fill_reply_hdr);
 233
 234/**
 235 * fc_fc4_conf_lport_params() - Modify "service_params" of specified lport
 236 * if there is service provider (target provider) registered with libfc
 237 * for specified "fc_ft_type"
 238 * @lport: Local port which service_params needs to be modified
 239 * @type: FC-4 type, such as FC_TYPE_FCP
 240 */
 241void fc_fc4_conf_lport_params(struct fc_lport *lport, enum fc_fh_type type)
 242{
 243        struct fc4_prov *prov_entry;
 244        BUG_ON(type >= FC_FC4_PROV_SIZE);
 245        BUG_ON(!lport);
 246        prov_entry = fc_passive_prov[type];
 247        if (type == FC_TYPE_FCP) {
 248                if (prov_entry && prov_entry->recv)
 249                        lport->service_params |= FCP_SPPF_TARG_FCN;
 250        }
 251}
 252
 253void fc_lport_iterate(void (*notify)(struct fc_lport *, void *), void *arg)
 254{
 255        struct fc_lport *lport;
 256
 257        mutex_lock(&fc_prov_mutex);
 258        list_for_each_entry(lport, &fc_local_ports, lport_list)
 259                notify(lport, arg);
 260        mutex_unlock(&fc_prov_mutex);
 261}
 262EXPORT_SYMBOL(fc_lport_iterate);
 263
 264/**
 265 * fc_fc4_register_provider() - register FC-4 upper-level provider.
 266 * @type: FC-4 type, such as FC_TYPE_FCP
 267 * @prov: structure describing provider including ops vector.
 268 *
 269 * Returns 0 on success, negative error otherwise.
 270 */
 271int fc_fc4_register_provider(enum fc_fh_type type, struct fc4_prov *prov)
 272{
 273        struct fc4_prov **prov_entry;
 274        int ret = 0;
 275
 276        if (type >= FC_FC4_PROV_SIZE)
 277                return -EINVAL;
 278        mutex_lock(&fc_prov_mutex);
 279        prov_entry = (prov->recv ? fc_passive_prov : fc_active_prov) + type;
 280        if (*prov_entry)
 281                ret = -EBUSY;
 282        else
 283                *prov_entry = prov;
 284        mutex_unlock(&fc_prov_mutex);
 285        return ret;
 286}
 287EXPORT_SYMBOL(fc_fc4_register_provider);
 288
 289/**
 290 * fc_fc4_deregister_provider() - deregister FC-4 upper-level provider.
 291 * @type: FC-4 type, such as FC_TYPE_FCP
 292 * @prov: structure describing provider including ops vector.
 293 */
 294void fc_fc4_deregister_provider(enum fc_fh_type type, struct fc4_prov *prov)
 295{
 296        BUG_ON(type >= FC_FC4_PROV_SIZE);
 297        mutex_lock(&fc_prov_mutex);
 298        if (prov->recv)
 299                RCU_INIT_POINTER(fc_passive_prov[type], NULL);
 300        else
 301                RCU_INIT_POINTER(fc_active_prov[type], NULL);
 302        mutex_unlock(&fc_prov_mutex);
 303        synchronize_rcu();
 304}
 305EXPORT_SYMBOL(fc_fc4_deregister_provider);
 306
 307/**
 308 * fc_fc4_add_lport() - add new local port to list and run notifiers.
 309 * @lport:  The new local port.
 310 */
 311void fc_fc4_add_lport(struct fc_lport *lport)
 312{
 313        mutex_lock(&fc_prov_mutex);
 314        list_add_tail(&lport->lport_list, &fc_local_ports);
 315        blocking_notifier_call_chain(&fc_lport_notifier_head,
 316                                     FC_LPORT_EV_ADD, lport);
 317        mutex_unlock(&fc_prov_mutex);
 318}
 319
 320/**
 321 * fc_fc4_del_lport() - remove local port from list and run notifiers.
 322 * @lport:  The new local port.
 323 */
 324void fc_fc4_del_lport(struct fc_lport *lport)
 325{
 326        mutex_lock(&fc_prov_mutex);
 327        list_del(&lport->lport_list);
 328        blocking_notifier_call_chain(&fc_lport_notifier_head,
 329                                     FC_LPORT_EV_DEL, lport);
 330        mutex_unlock(&fc_prov_mutex);
 331}
 332