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
  25 #include <scsi/libfc.h>
  26 #include <scsi/fc_encode.h>
  27
  28 #include "fc_libfc.h"
  29
  30 MODULE_AUTHOR("Open-FCoE.org");
  31 MODULE_DESCRIPTION("libfc");
  32 MODULE_LICENSE("GPL v2");
  33
  34 unsigned int fc_debug_logging;
  35 module_param_named(debug_logging, fc_debug_logging, int, S_IRUGO|S_IWUSR);
  36 MODULE_PARM_DESC(debug_logging, "a bit mask of logging levels");
  37
  38 DEFINE_MUTEX(fc_prov_mutex);
  39 static LIST_HEAD(fc_local_ports);
  40 struct blocking_notifier_head fc_lport_notifier_head =
  41                 BLOCKING_NOTIFIER_INIT(fc_lport_notifier_head);
  42 EXPORT_SYMBOL(fc_lport_notifier_head);
  43
  44 /*
  45  * Providers which primarily send requests and PRLIs.
  46  */
  47 struct fc4_prov *fc_active_prov[FC_FC4_PROV_SIZE] = {
  48         [0] = &fc_rport_t0_prov,
  49         [FC_TYPE_FCP] = &fc_rport_fcp_init,
  50 };
  51
  52 /*
  53  * Providers which receive requests.
  54  */
  55 struct fc4_prov *fc_passive_prov[FC_FC4_PROV_SIZE] = {
  56         [FC_TYPE_ELS] = &fc_lport_els_prov,
  57 };
  58
  59 /**
  60  * libfc_init() - Initialize libfc.ko
  61  */
  62 static int __init libfc_init(void)
  63 {
  64         int rc = 0;
  65
  66         rc = fc_setup_fcp();
  67         if (rc)
  68                 return rc;
  69
  70         rc = fc_setup_exch_mgr();
  71         if (rc)
  72                 goto destroy_pkt_cache;
  73
  74         rc = fc_setup_rport();
  75         if (rc)
  76                 goto destroy_em;
  77
  78         return rc;
  79 destroy_em:
  80         fc_destroy_exch_mgr();
  81 destroy_pkt_cache:
  82         fc_destroy_fcp();
  83         return rc;
  84 }
  85 module_init(libfc_init);
  86
  87 /**
  88  * libfc_exit() - Tear down libfc.ko
  89  */
  90 static void __exit libfc_exit(void)
  91 {
  92         fc_destroy_fcp();
  93         fc_destroy_exch_mgr();
  94         fc_destroy_rport();
  95 }
  96 module_exit(libfc_exit);
  97
  98 /**
  99  * fc_copy_buffer_to_sglist() - This routine copies the data of a buffer
 100  *                              into a scatter-gather list (SG list).
 101  *
 102  * @buf: pointer to the data buffer.
 103  * @len: the byte-length of the data buffer.
 104  * @sg: pointer to the pointer of the SG list.
 105  * @nents: pointer to the remaining number of entries in the SG list.
 106  * @offset: pointer to the current offset in the SG list.
 107  * @km_type: dedicated page table slot type for kmap_atomic.
 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                              enum km_type km_type, 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                                         km_type);
 146                 if (crc)
 147                         *crc = crc32(*crc, buf, sg_bytes);
 148                 memcpy((char *)page_addr + (off & ~PAGE_MASK), buf, sg_bytes);
 149                 kunmap_atomic(page_addr, km_type);
 150                 buf += sg_bytes;
 151                 *offset += sg_bytes;
 152                 remaining -= sg_bytes;
 153                 copy_len += sg_bytes;
 154         }
 155         return copy_len;
 156 }
 157
 158 /**
 159  * fc_fill_hdr() -  fill FC header fields based on request
 160  * @fp: reply frame containing header to be filled in
 161  * @in_fp: request frame containing header to use in filling in reply
 162  * @r_ctl: R_CTL value for header
 163  * @f_ctl: F_CTL value for header, with 0 pad
 164  * @seq_cnt: sequence count for the header, ignored if frame has a sequence
 165  * @parm_offset: parameter / offset value
 166  */
 167 void fc_fill_hdr(struct fc_frame *fp, const struct fc_frame *in_fp,
 168                  enum fc_rctl r_ctl, u32 f_ctl, u16 seq_cnt, u32 parm_offset)
 169 {
 170         struct fc_frame_header *fh;
 171         struct fc_frame_header *in_fh;
 172         struct fc_seq *sp;
 173         u32 fill;
 174
 175         fh = __fc_frame_header_get(fp);
 176         in_fh = __fc_frame_header_get(in_fp);
 177
 178         if (f_ctl & FC_FC_END_SEQ) {
 179                 fill = -fr_len(fp) & 3;
 180                 if (fill) {
 181                         /* TODO, this may be a problem with fragmented skb */
 182                         memset(skb_put(fp_skb(fp), fill), 0, fill);
 183                         f_ctl |= fill;
 184                 }
 185                 fr_eof(fp) = FC_EOF_T;
 186         } else {
 187                 WARN_ON(fr_len(fp) % 4 != 0);   /* no pad to non last frame */
 188                 fr_eof(fp) = FC_EOF_N;
 189         }
 190
 191         fh->fh_r_ctl = r_ctl;
 192         memcpy(fh->fh_d_id, in_fh->fh_s_id, sizeof(fh->fh_d_id));
 193         memcpy(fh->fh_s_id, in_fh->fh_d_id, sizeof(fh->fh_s_id));
 194         fh->fh_type = in_fh->fh_type;
 195         hton24(fh->fh_f_ctl, f_ctl);
 196         fh->fh_ox_id = in_fh->fh_ox_id;
 197         fh->fh_rx_id = in_fh->fh_rx_id;
 198         fh->fh_cs_ctl = 0;
 199         fh->fh_df_ctl = 0;
 200         fh->fh_parm_offset = htonl(parm_offset);
 201
 202         sp = fr_seq(in_fp);
 203         if (sp) {
 204                 fr_seq(fp) = sp;
 205                 fh->fh_seq_id = sp->id;
 206                 seq_cnt = sp->cnt;
 207         } else {
 208                 fh->fh_seq_id = 0;
 209         }
 210         fh->fh_seq_cnt = ntohs(seq_cnt);
 211         fr_sof(fp) = seq_cnt ? FC_SOF_N3 : FC_SOF_I3;
 212         fr_encaps(fp) = fr_encaps(in_fp);
 213 }
 214 EXPORT_SYMBOL(fc_fill_hdr);
 215
 216 /**
 217  * fc_fill_reply_hdr() -  fill FC reply header fields based on request
 218  * @fp: reply frame containing header to be filled in
 219  * @in_fp: request frame containing header to use in filling in reply
 220  * @r_ctl: R_CTL value for reply
 221  * @parm_offset: parameter / offset value
 222  */
 223 void fc_fill_reply_hdr(struct fc_frame *fp, const struct fc_frame *in_fp,
 224                        enum fc_rctl r_ctl, u32 parm_offset)
 225 {
 226         struct fc_seq *sp;
 227
 228         sp = fr_seq(in_fp);
 229         if (sp)
 230                 fr_seq(fp) = fr_dev(in_fp)->tt.seq_start_next(sp);
 231         fc_fill_hdr(fp, in_fp, r_ctl, FC_FCTL_RESP, 0, parm_offset);
 232 }
 233 EXPORT_SYMBOL(fc_fill_reply_hdr);
 234
 235 /**
 236  * fc_fc4_conf_lport_params() - Modify "service_params" of specified lport
 237  * if there is service provider (target provider) registered with libfc
 238  * for specified "fc_ft_type"
 239  * @lport: Local port which service_params needs to be modified
 240  * @type: FC-4 type, such as FC_TYPE_FCP
 241  */
 242 void fc_fc4_conf_lport_params(struct fc_lport *lport, enum fc_fh_type type)
 243 {
 244         struct fc4_prov *prov_entry;
 245         BUG_ON(type >= FC_FC4_PROV_SIZE);
 246         BUG_ON(!lport);
 247         prov_entry = fc_passive_prov[type];
 248         if (type == FC_TYPE_FCP) {
 249                 if (prov_entry && prov_entry->recv)
 250                         lport->service_params |= FCP_SPPF_TARG_FCN;
 251         }
 252 }
 253
 254 void fc_lport_iterate(void (*notify)(struct fc_lport *, void *), void *arg)
 255 {
 256         struct fc_lport *lport;
 257
 258         mutex_lock(&fc_prov_mutex);
 259         list_for_each_entry(lport, &fc_local_ports, lport_list)
 260                 notify(lport, arg);
 261         mutex_unlock(&fc_prov_mutex);
 262 }
 263 EXPORT_SYMBOL(fc_lport_iterate);
 264
 265 /**
 266  * fc_fc4_register_provider() - register FC-4 upper-level provider.
 267  * @type: FC-4 type, such as FC_TYPE_FCP
 268  * @prov: structure describing provider including ops vector.
 269  *
 270  * Returns 0 on success, negative error otherwise.
 271  */
 272 int fc_fc4_register_provider(enum fc_fh_type type, struct fc4_prov *prov)
 273 {
 274         struct fc4_prov **prov_entry;
 275         int ret = 0;
 276
 277         if (type >= FC_FC4_PROV_SIZE)
 278                 return -EINVAL;
 279         mutex_lock(&fc_prov_mutex);
 280         prov_entry = (prov->recv ? fc_passive_prov : fc_active_prov) + type;
 281         if (*prov_entry)
 282                 ret = -EBUSY;
 283         else
 284                 *prov_entry = prov;
 285         mutex_unlock(&fc_prov_mutex);
 286         return ret;
 287 }
 288 EXPORT_SYMBOL(fc_fc4_register_provider);
 289
 290 /**
 291  * fc_fc4_deregister_provider() - deregister FC-4 upper-level provider.
 292  * @type: FC-4 type, such as FC_TYPE_FCP
 293  * @prov: structure describing provider including ops vector.
 294  */
 295 void fc_fc4_deregister_provider(enum fc_fh_type type, struct fc4_prov *prov)
 296 {
 297         BUG_ON(type >= FC_FC4_PROV_SIZE);
 298         mutex_lock(&fc_prov_mutex);
 299         if (prov->recv)
 300                 rcu_assign_pointer(fc_passive_prov[type], NULL);
 301         else
 302                 rcu_assign_pointer(fc_active_prov[type], NULL);
 303         mutex_unlock(&fc_prov_mutex);
 304         synchronize_rcu();
 305 }
 306 EXPORT_SYMBOL(fc_fc4_deregister_provider);
 307
 308 /**
 309  * fc_fc4_add_lport() - add new local port to list and run notifiers.
 310  * @lport:  The new local port.
 311  */
 312 void fc_fc4_add_lport(struct fc_lport *lport)
 313 {
 314         mutex_lock(&fc_prov_mutex);
 315         list_add_tail(&lport->lport_list, &fc_local_ports);
 316         blocking_notifier_call_chain(&fc_lport_notifier_head,
 317                                      FC_LPORT_EV_ADD, lport);
 318         mutex_unlock(&fc_prov_mutex);
 319 }
 320
 321 /**
 322  * fc_fc4_del_lport() - remove local port from list and run notifiers.
 323  * @lport:  The new local port.
 324  */
 325 void fc_fc4_del_lport(struct fc_lport *lport)
 326 {
 327         mutex_lock(&fc_prov_mutex);
 328         list_del(&lport->lport_list);
 329         blocking_notifier_call_chain(&fc_lport_notifier_head,
 330                                      FC_LPORT_EV_DEL, lport);
 331         mutex_unlock(&fc_prov_mutex);
 332 }