drivers/scsi/libfc/fc_libfc.c

   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
  31 MODULE_AUTHOR("Open-FCoE.org");
  32 MODULE_DESCRIPTION("libfc");
  33 MODULE_LICENSE("GPL v2");
  34
  35 unsigned int fc_debug_logging;
  36 module_param_named(debug_logging, fc_debug_logging, int, S_IRUGO|S_IWUSR);
  37 MODULE_PARM_DESC(debug_logging, "a bit mask of logging levels");
  38
  39 DEFINE_MUTEX(fc_prov_mutex);
  40 static LIST_HEAD(fc_local_ports);
  41 struct blocking_notifier_head fc_lport_notifier_head =
  42                 BLOCKING_NOTIFIER_INIT(fc_lport_notifier_head);
  43 EXPORT_SYMBOL(fc_lport_notifier_head);
  44
  45 /*
  46  * Providers which primarily send requests and PRLIs.
  47  */
  48 struct 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  */
  56 struct 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  */
  63 static 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;
  80 destroy_em:
  81         fc_destroy_exch_mgr();
  82 destroy_pkt_cache:
  83         fc_destroy_fcp();
  84         return rc;
  85 }
  86 module_init(libfc_init);
  87
  88 /**
  89  * libfc_exit() - Tear down libfc.ko
  90  */
  91 static void __exit libfc_exit(void)
  92 {
  93         fc_destroy_fcp();
  94         fc_destroy_exch_mgr();
  95         fc_destroy_rport();
  96 }
  97 module_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  */
 111 u32 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  */
 166 void 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                         memset(skb_put(fp_skb(fp), fill), 0, 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 }
 213 EXPORT_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  */
 222 void 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 }
 232 EXPORT_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  */
 241 void 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
 253 void 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 }
 262 EXPORT_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  */
 271 int 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 }
 287 EXPORT_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  */
 294 void 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 }
 305 EXPORT_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  */
 311 void 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  */
 324 void 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 }