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  * @km_type: dedicated page table slot type for kmap_atomic.
 109  * @crc: pointer to the 32-bit crc value.
 110  *       If crc is NULL, CRC is not calculated.
 111  */
 112 u32 fc_copy_buffer_to_sglist(void *buf, size_t len,
 113                              struct scatterlist *sg,
 114                              u32 *nents, size_t *offset,
 115                              enum km_type km_type, u32 *crc)
 116 {
 117         size_t remaining = len;
 118         u32 copy_len = 0;
 119
 120         while (remaining > 0 && sg) {
 121                 size_t off, sg_bytes;
 122                 void *page_addr;
 123
 124                 if (*offset >= sg->length) {
 125                         /*
 126                          * Check for end and drop resources
 127                          * from the last iteration.
 128                          */
 129                         if (!(*nents))
 130                                 break;
 131                         --(*nents);
 132                         *offset -= sg->length;
 133                         sg = sg_next(sg);
 134                         continue;
 135                 }
 136                 sg_bytes = min(remaining, sg->length - *offset);
 137
 138                 /*
 139                  * The scatterlist item may be bigger than PAGE_SIZE,
 140                  * but we are limited to mapping PAGE_SIZE at a time.
 141                  */
 142                 off = *offset + sg->offset;
 143                 sg_bytes = min(sg_bytes,
 144                                (size_t)(PAGE_SIZE - (off & ~PAGE_MASK)));
 145                 page_addr = kmap_atomic(sg_page(sg) + (off >> PAGE_SHIFT),
 146                                         km_type);
 147                 if (crc)
 148                         *crc = crc32(*crc, buf, sg_bytes);
 149                 memcpy((char *)page_addr + (off & ~PAGE_MASK), buf, sg_bytes);
 150                 kunmap_atomic(page_addr, km_type);
 151                 buf += sg_bytes;
 152                 *offset += sg_bytes;
 153                 remaining -= sg_bytes;
 154                 copy_len += sg_bytes;
 155         }
 156         return copy_len;
 157 }
 158
 159 /**
 160  * fc_fill_hdr() -  fill FC header fields based on request
 161  * @fp: reply frame containing header to be filled in
 162  * @in_fp: request frame containing header to use in filling in reply
 163  * @r_ctl: R_CTL value for header
 164  * @f_ctl: F_CTL value for header, with 0 pad
 165  * @seq_cnt: sequence count for the header, ignored if frame has a sequence
 166  * @parm_offset: parameter / offset value
 167  */
 168 void fc_fill_hdr(struct fc_frame *fp, const struct fc_frame *in_fp,
 169                  enum fc_rctl r_ctl, u32 f_ctl, u16 seq_cnt, u32 parm_offset)
 170 {
 171         struct fc_frame_header *fh;
 172         struct fc_frame_header *in_fh;
 173         struct fc_seq *sp;
 174         u32 fill;
 175
 176         fh = __fc_frame_header_get(fp);
 177         in_fh = __fc_frame_header_get(in_fp);
 178
 179         if (f_ctl & FC_FC_END_SEQ) {
 180                 fill = -fr_len(fp) & 3;
 181                 if (fill) {
 182                         /* TODO, this may be a problem with fragmented skb */
 183                         memset(skb_put(fp_skb(fp), fill), 0, fill);
 184                         f_ctl |= fill;
 185                 }
 186                 fr_eof(fp) = FC_EOF_T;
 187         } else {
 188                 WARN_ON(fr_len(fp) % 4 != 0);   /* no pad to non last frame */
 189                 fr_eof(fp) = FC_EOF_N;
 190         }
 191
 192         fh->fh_r_ctl = r_ctl;
 193         memcpy(fh->fh_d_id, in_fh->fh_s_id, sizeof(fh->fh_d_id));
 194         memcpy(fh->fh_s_id, in_fh->fh_d_id, sizeof(fh->fh_s_id));
 195         fh->fh_type = in_fh->fh_type;
 196         hton24(fh->fh_f_ctl, f_ctl);
 197         fh->fh_ox_id = in_fh->fh_ox_id;
 198         fh->fh_rx_id = in_fh->fh_rx_id;
 199         fh->fh_cs_ctl = 0;
 200         fh->fh_df_ctl = 0;
 201         fh->fh_parm_offset = htonl(parm_offset);
 202
 203         sp = fr_seq(in_fp);
 204         if (sp) {
 205                 fr_seq(fp) = sp;
 206                 fh->fh_seq_id = sp->id;
 207                 seq_cnt = sp->cnt;
 208         } else {
 209                 fh->fh_seq_id = 0;
 210         }
 211         fh->fh_seq_cnt = ntohs(seq_cnt);
 212         fr_sof(fp) = seq_cnt ? FC_SOF_N3 : FC_SOF_I3;
 213         fr_encaps(fp) = fr_encaps(in_fp);
 214 }
 215 EXPORT_SYMBOL(fc_fill_hdr);
 216
 217 /**
 218  * fc_fill_reply_hdr() -  fill FC reply header fields based on request
 219  * @fp: reply frame containing header to be filled in
 220  * @in_fp: request frame containing header to use in filling in reply
 221  * @r_ctl: R_CTL value for reply
 222  * @parm_offset: parameter / offset value
 223  */
 224 void fc_fill_reply_hdr(struct fc_frame *fp, const struct fc_frame *in_fp,
 225                        enum fc_rctl r_ctl, u32 parm_offset)
 226 {
 227         struct fc_seq *sp;
 228
 229         sp = fr_seq(in_fp);
 230         if (sp)
 231                 fr_seq(fp) = fr_dev(in_fp)->tt.seq_start_next(sp);
 232         fc_fill_hdr(fp, in_fp, r_ctl, FC_FCTL_RESP, 0, parm_offset);
 233 }
 234 EXPORT_SYMBOL(fc_fill_reply_hdr);
 235
 236 /**
 237  * fc_fc4_conf_lport_params() - Modify "service_params" of specified lport
 238  * if there is service provider (target provider) registered with libfc
 239  * for specified "fc_ft_type"
 240  * @lport: Local port which service_params needs to be modified
 241  * @type: FC-4 type, such as FC_TYPE_FCP
 242  */
 243 void fc_fc4_conf_lport_params(struct fc_lport *lport, enum fc_fh_type type)
 244 {
 245         struct fc4_prov *prov_entry;
 246         BUG_ON(type >= FC_FC4_PROV_SIZE);
 247         BUG_ON(!lport);
 248         prov_entry = fc_passive_prov[type];
 249         if (type == FC_TYPE_FCP) {
 250                 if (prov_entry && prov_entry->recv)
 251                         lport->service_params |= FCP_SPPF_TARG_FCN;
 252         }
 253 }
 254
 255 void fc_lport_iterate(void (*notify)(struct fc_lport *, void *), void *arg)
 256 {
 257         struct fc_lport *lport;
 258
 259         mutex_lock(&fc_prov_mutex);
 260         list_for_each_entry(lport, &fc_local_ports, lport_list)
 261                 notify(lport, arg);
 262         mutex_unlock(&fc_prov_mutex);
 263 }
 264 EXPORT_SYMBOL(fc_lport_iterate);
 265
 266 /**
 267  * fc_fc4_register_provider() - register FC-4 upper-level provider.
 268  * @type: FC-4 type, such as FC_TYPE_FCP
 269  * @prov: structure describing provider including ops vector.
 270  *
 271  * Returns 0 on success, negative error otherwise.
 272  */
 273 int fc_fc4_register_provider(enum fc_fh_type type, struct fc4_prov *prov)
 274 {
 275         struct fc4_prov **prov_entry;
 276         int ret = 0;
 277
 278         if (type >= FC_FC4_PROV_SIZE)
 279                 return -EINVAL;
 280         mutex_lock(&fc_prov_mutex);
 281         prov_entry = (prov->recv ? fc_passive_prov : fc_active_prov) + type;
 282         if (*prov_entry)
 283                 ret = -EBUSY;
 284         else
 285                 *prov_entry = prov;
 286         mutex_unlock(&fc_prov_mutex);
 287         return ret;
 288 }
 289 EXPORT_SYMBOL(fc_fc4_register_provider);
 290
 291 /**
 292  * fc_fc4_deregister_provider() - deregister FC-4 upper-level provider.
 293  * @type: FC-4 type, such as FC_TYPE_FCP
 294  * @prov: structure describing provider including ops vector.
 295  */
 296 void fc_fc4_deregister_provider(enum fc_fh_type type, struct fc4_prov *prov)
 297 {
 298         BUG_ON(type >= FC_FC4_PROV_SIZE);
 299         mutex_lock(&fc_prov_mutex);
 300         if (prov->recv)
 301                 rcu_assign_pointer(fc_passive_prov[type], NULL);
 302         else
 303                 rcu_assign_pointer(fc_active_prov[type], NULL);
 304         mutex_unlock(&fc_prov_mutex);
 305         synchronize_rcu();
 306 }
 307 EXPORT_SYMBOL(fc_fc4_deregister_provider);
 308
 309 /**
 310  * fc_fc4_add_lport() - add new local port to list and run notifiers.
 311  * @lport:  The new local port.
 312  */
 313 void fc_fc4_add_lport(struct fc_lport *lport)
 314 {
 315         mutex_lock(&fc_prov_mutex);
 316         list_add_tail(&lport->lport_list, &fc_local_ports);
 317         blocking_notifier_call_chain(&fc_lport_notifier_head,
 318                                      FC_LPORT_EV_ADD, lport);
 319         mutex_unlock(&fc_prov_mutex);
 320 }
 321
 322 /**
 323  * fc_fc4_del_lport() - remove local port from list and run notifiers.
 324  * @lport:  The new local port.
 325  */
 326 void fc_fc4_del_lport(struct fc_lport *lport)
 327 {
 328         mutex_lock(&fc_prov_mutex);
 329         list_del(&lport->lport_list);
 330         blocking_notifier_call_chain(&fc_lport_notifier_head,
 331                                      FC_LPORT_EV_DEL, lport);
 332         mutex_unlock(&fc_prov_mutex);
 333 }