drivers/target/tcm_fc/tfc_io.c

   1 /*
   2  * Copyright (c) 2010 Cisco Systems, Inc.
   3  *
   4  * Portions based on tcm_loop_fabric_scsi.c and libfc/fc_fcp.c
   5  *
   6  * Copyright (c) 2007 Intel Corporation. All rights reserved.
   7  * Copyright (c) 2008 Red Hat, Inc.  All rights reserved.
   8  * Copyright (c) 2008 Mike Christie
   9  * Copyright (c) 2009 Rising Tide, Inc.
  10  * Copyright (c) 2009 Linux-iSCSI.org
  11  * Copyright (c) 2009 Nicholas A. Bellinger <nab@linux-iscsi.org>
  12  *
  13  * This program is free software; you can redistribute it and/or modify it
  14  * under the terms and conditions of the GNU General Public License,
  15  * version 2, as published by the Free Software Foundation.
  16  *
  17  * This program is distributed in the hope it will be useful, but WITHOUT
  18  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  19  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  20  * more details.
  21  *
  22  * You should have received a copy of the GNU General Public License along with
  23  * this program; if not, write to the Free Software Foundation, Inc.,
  24  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  25  */
  26
  27 /* XXX TBD some includes may be extraneous */
  28
  29 #include <linux/module.h>
  30 #include <linux/moduleparam.h>
  31 #include <linux/version.h>
  32 #include <generated/utsrelease.h>
  33 #include <linux/utsname.h>
  34 #include <linux/init.h>
  35 #include <linux/slab.h>
  36 #include <linux/kthread.h>
  37 #include <linux/types.h>
  38 #include <linux/string.h>
  39 #include <linux/configfs.h>
  40 #include <linux/ctype.h>
  41 #include <linux/hash.h>
  42 #include <asm/unaligned.h>
  43 #include <scsi/scsi.h>
  44 #include <scsi/scsi_host.h>
  45 #include <scsi/scsi_device.h>
  46 #include <scsi/scsi_cmnd.h>
  47 #include <scsi/libfc.h>
  48 #include <scsi/fc_encode.h>
  49
  50 #include <target/target_core_base.h>
  51 #include <target/target_core_transport.h>
  52 #include <target/target_core_fabric_ops.h>
  53 #include <target/target_core_device.h>
  54 #include <target/target_core_tpg.h>
  55 #include <target/target_core_configfs.h>
  56 #include <target/target_core_base.h>
  57 #include <target/configfs_macros.h>
  58
  59 #include "tcm_fc.h"
  60
  61 /*
  62  * Deliver read data back to initiator.
  63  * XXX TBD handle resource problems later.
  64  */
  65 int ft_queue_data_in(struct se_cmd *se_cmd)
  66 {
  67         struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
  68         struct se_transport_task *task;
  69         struct fc_frame *fp = NULL;
  70         struct fc_exch *ep;
  71         struct fc_lport *lport;
  72         struct se_mem *mem;
  73         size_t remaining;
  74         u32 f_ctl = FC_FC_EX_CTX | FC_FC_REL_OFF;
  75         u32 mem_off;
  76         u32 fh_off = 0;
  77         u32 frame_off = 0;
  78         size_t frame_len = 0;
  79         size_t mem_len;
  80         size_t tlen;
  81         size_t off_in_page;
  82         struct page *page;
  83         int use_sg;
  84         int error;
  85         void *page_addr;
  86         void *from;
  87         void *to = NULL;
  88
  89         ep = fc_seq_exch(cmd->seq);
  90         lport = ep->lp;
  91         cmd->seq = lport->tt.seq_start_next(cmd->seq);
  92
  93         task = &se_cmd->t_task;
  94         remaining = se_cmd->data_length;
  95
  96         /*
  97          * Setup to use first mem list entry if any.
  98          */
  99         if (task->t_tasks_se_num) {
 100                 mem = list_first_entry(&task->t_mem_list,
 101                          struct se_mem, se_list);
 102                 mem_len = mem->se_len;
 103                 mem_off = mem->se_off;
 104                 page = mem->se_page;
 105         } else {
 106                 mem = NULL;
 107                 mem_len = remaining;
 108                 mem_off = 0;
 109                 page = NULL;
 110         }
 111
 112         /* no scatter/gather in skb for odd word length due to fc_seq_send() */
 113         use_sg = !(remaining % 4);
 114
 115         while (remaining) {
 116                 if (!mem_len) {
 117                         BUG_ON(!mem);
 118                         mem = list_entry(mem->se_list.next,
 119                                 struct se_mem, se_list);
 120                         mem_len = min((size_t)mem->se_len, remaining);
 121                         mem_off = mem->se_off;
 122                         page = mem->se_page;
 123                 }
 124                 if (!frame_len) {
 125                         /*
 126                          * If lport's has capability of Large Send Offload LSO)
 127                          * , then allow 'frame_len' to be as big as 'lso_max'
 128                          * if indicated transfer length is >= lport->lso_max
 129                          */
 130                         frame_len = (lport->seq_offload) ? lport->lso_max :
 131                                                           cmd->sess->max_frame;
 132                         frame_len = min(frame_len, remaining);
 133                         fp = fc_frame_alloc(lport, use_sg ? 0 : frame_len);
 134                         if (!fp)
 135                                 return -ENOMEM;
 136                         to = fc_frame_payload_get(fp, 0);
 137                         fh_off = frame_off;
 138                         frame_off += frame_len;
 139                         /*
 140                          * Setup the frame's max payload which is used by base
 141                          * driver to indicate HW about max frame size, so that
 142                          * HW can do fragmentation appropriately based on
 143                          * "gso_max_size" of underline netdev.
 144                          */
 145                         fr_max_payload(fp) = cmd->sess->max_frame;
 146                 }
 147                 tlen = min(mem_len, frame_len);
 148
 149                 if (use_sg) {
 150                         if (!mem) {
 151                                 BUG_ON(!task->t_task_buf);
 152                                 page_addr = task->t_task_buf + mem_off;
 153                                 /*
 154                                  * In this case, offset is 'offset_in_page' of
 155                                  * (t_task_buf + mem_off) instead of 'mem_off'.
 156                                  */
 157                                 off_in_page = offset_in_page(page_addr);
 158                                 page = virt_to_page(page_addr);
 159                                 tlen = min(tlen, PAGE_SIZE - off_in_page);
 160                         } else
 161                                 off_in_page = mem_off;
 162                         BUG_ON(!page);
 163                         get_page(page);
 164                         skb_fill_page_desc(fp_skb(fp),
 165                                            skb_shinfo(fp_skb(fp))->nr_frags,
 166                                            page, off_in_page, tlen);
 167                         fr_len(fp) += tlen;
 168                         fp_skb(fp)->data_len += tlen;
 169                         fp_skb(fp)->truesize +=
 170                                         PAGE_SIZE << compound_order(page);
 171                 } else if (mem) {
 172                         BUG_ON(!page);
 173                         from = kmap_atomic(page + (mem_off >> PAGE_SHIFT),
 174                                            KM_SOFTIRQ0);
 175                         page_addr = from;
 176                         from += mem_off & ~PAGE_MASK;
 177                         tlen = min(tlen, (size_t)(PAGE_SIZE -
 178                                                 (mem_off & ~PAGE_MASK)));
 179                         memcpy(to, from, tlen);
 180                         kunmap_atomic(page_addr, KM_SOFTIRQ0);
 181                         to += tlen;
 182                 } else {
 183                         from = task->t_task_buf + mem_off;
 184                         memcpy(to, from, tlen);
 185                         to += tlen;
 186                 }
 187
 188                 mem_off += tlen;
 189                 mem_len -= tlen;
 190                 frame_len -= tlen;
 191                 remaining -= tlen;
 192
 193                 if (frame_len &&
 194                     (skb_shinfo(fp_skb(fp))->nr_frags < FC_FRAME_SG_LEN))
 195                         continue;
 196                 if (!remaining)
 197                         f_ctl |= FC_FC_END_SEQ;
 198                 fc_fill_fc_hdr(fp, FC_RCTL_DD_SOL_DATA, ep->did, ep->sid,
 199                                FC_TYPE_FCP, f_ctl, fh_off);
 200                 error = lport->tt.seq_send(lport, cmd->seq, fp);
 201                 if (error) {
 202                         /* XXX For now, initiator will retry */
 203                         if (printk_ratelimit())
 204                                 printk(KERN_ERR "%s: Failed to send frame %p, "
 205                                                 "xid <0x%x>, remaining %zu, "
 206                                                 "lso_max <0x%x>\n",
 207                                                 __func__, fp, ep->xid,
 208                                                 remaining, lport->lso_max);
 209                 }
 210         }
 211         return ft_queue_status(se_cmd);
 212 }
 213
 214 /*
 215  * Receive write data frame.
 216  */
 217 void ft_recv_write_data(struct ft_cmd *cmd, struct fc_frame *fp)
 218 {
 219         struct se_cmd *se_cmd = &cmd->se_cmd;
 220         struct fc_seq *seq = cmd->seq;
 221         struct fc_exch *ep;
 222         struct fc_lport *lport;
 223         struct se_transport_task *task;
 224         struct fc_frame_header *fh;
 225         struct se_mem *mem;
 226         u32 mem_off;
 227         u32 rel_off;
 228         size_t frame_len;
 229         size_t mem_len;
 230         size_t tlen;
 231         struct page *page;
 232         void *page_addr;
 233         void *from;
 234         void *to;
 235         u32 f_ctl;
 236         void *buf;
 237
 238         task = &se_cmd->t_task;
 239
 240         fh = fc_frame_header_get(fp);
 241         if (!(ntoh24(fh->fh_f_ctl) & FC_FC_REL_OFF))
 242                 goto drop;
 243
 244         /*
 245          * Doesn't expect even single byte of payload. Payload
 246          * is expected to be copied directly to user buffers
 247          * due to DDP (Large Rx offload) feature, hence
 248          * BUG_ON if BUF is non-NULL
 249          */
 250         buf = fc_frame_payload_get(fp, 1);
 251         if (cmd->was_ddp_setup && buf) {
 252                 printk(KERN_INFO "%s: When DDP was setup, not expected to"
 253                                  "receive frame with payload, Payload shall be"
 254                                  "copied directly to buffer instead of coming "
 255                                  "via. legacy receive queues\n", __func__);
 256                 BUG_ON(buf);
 257         }
 258
 259         /*
 260          * If ft_cmd indicated 'ddp_setup', in that case only the last frame
 261          * should come with 'TSI bit being set'. If 'TSI bit is not set and if
 262          * data frame appears here, means error condition. In both the cases
 263          * release the DDP context (ddp_put) and in error case, as well
 264          * initiate error recovery mechanism.
 265          */
 266         ep = fc_seq_exch(seq);
 267         if (cmd->was_ddp_setup) {
 268                 BUG_ON(!ep);
 269                 lport = ep->lp;
 270                 BUG_ON(!lport);
 271         }
 272         if (cmd->was_ddp_setup && ep->xid != FC_XID_UNKNOWN) {
 273                 f_ctl = ntoh24(fh->fh_f_ctl);
 274                 /*
 275                  * If TSI bit set in f_ctl, means last write data frame is
 276                  * received successfully where payload is posted directly
 277                  * to user buffer and only the last frame's header is posted
 278                  * in legacy receive queue
 279                  */
 280                 if (f_ctl & FC_FC_SEQ_INIT) { /* TSI bit set in FC frame */
 281                         cmd->write_data_len = lport->tt.ddp_done(lport,
 282                                                                 ep->xid);
 283                         goto last_frame;
 284                 } else {
 285                         /*
 286                          * Updating the write_data_len may be meaningless at
 287                          * this point, but just in case if required in future
 288                          * for debugging or any other purpose
 289                          */
 290                         printk(KERN_ERR "%s: Received frame with TSI bit not"
 291                                         " being SET, dropping the frame, "
 292                                         "cmd->sg <%p>, cmd->sg_cnt <0x%x>\n",
 293                                         __func__, cmd->sg, cmd->sg_cnt);
 294                         cmd->write_data_len = lport->tt.ddp_done(lport,
 295                                                               ep->xid);
 296                         lport->tt.seq_exch_abort(cmd->seq, 0);
 297                         goto drop;
 298                 }
 299         }
 300
 301         rel_off = ntohl(fh->fh_parm_offset);
 302         frame_len = fr_len(fp);
 303         if (frame_len <= sizeof(*fh))
 304                 goto drop;
 305         frame_len -= sizeof(*fh);
 306         from = fc_frame_payload_get(fp, 0);
 307         if (rel_off >= se_cmd->data_length)
 308                 goto drop;
 309         if (frame_len + rel_off > se_cmd->data_length)
 310                 frame_len = se_cmd->data_length - rel_off;
 311
 312         /*
 313          * Setup to use first mem list entry if any.
 314          */
 315         if (task->t_tasks_se_num) {
 316                 mem = list_first_entry(&task->t_mem_list,
 317                                        struct se_mem, se_list);
 318                 mem_len = mem->se_len;
 319                 mem_off = mem->se_off;
 320                 page = mem->se_page;
 321         } else {
 322                 mem = NULL;
 323                 page = NULL;
 324                 mem_off = 0;
 325                 mem_len = frame_len;
 326         }
 327
 328         while (frame_len) {
 329                 if (!mem_len) {
 330                         BUG_ON(!mem);
 331                         mem = list_entry(mem->se_list.next,
 332                                          struct se_mem, se_list);
 333                         mem_len = mem->se_len;
 334                         mem_off = mem->se_off;
 335                         page = mem->se_page;
 336                 }
 337                 if (rel_off >= mem_len) {
 338                         rel_off -= mem_len;
 339                         mem_len = 0;
 340                         continue;
 341                 }
 342                 mem_off += rel_off;
 343                 mem_len -= rel_off;
 344                 rel_off = 0;
 345
 346                 tlen = min(mem_len, frame_len);
 347
 348                 if (mem) {
 349                         to = kmap_atomic(page + (mem_off >> PAGE_SHIFT),
 350                                          KM_SOFTIRQ0);
 351                         page_addr = to;
 352                         to += mem_off & ~PAGE_MASK;
 353                         tlen = min(tlen, (size_t)(PAGE_SIZE -
 354                                                 (mem_off & ~PAGE_MASK)));
 355                         memcpy(to, from, tlen);
 356                         kunmap_atomic(page_addr, KM_SOFTIRQ0);
 357                 } else {
 358                         to = task->t_task_buf + mem_off;
 359                         memcpy(to, from, tlen);
 360                 }
 361                 from += tlen;
 362                 frame_len -= tlen;
 363                 mem_off += tlen;
 364                 mem_len -= tlen;
 365                 cmd->write_data_len += tlen;
 366         }
 367 last_frame:
 368         if (cmd->write_data_len == se_cmd->data_length)
 369                 transport_generic_handle_data(se_cmd);
 370 drop:
 371         fc_frame_free(fp);
 372 }