linux/drivers/target/tcm_fc/tfc_io.c
<<
>>
Prefs
   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/utsname.h>
  32#include <linux/init.h>
  33#include <linux/slab.h>
  34#include <linux/kthread.h>
  35#include <linux/types.h>
  36#include <linux/string.h>
  37#include <linux/configfs.h>
  38#include <linux/ctype.h>
  39#include <linux/hash.h>
  40#include <linux/ratelimit.h>
  41#include <asm/unaligned.h>
  42#include <scsi/libfc.h>
  43#include <scsi/fc_encode.h>
  44
  45#include <target/target_core_base.h>
  46#include <target/target_core_fabric.h>
  47
  48#include "tcm_fc.h"
  49
  50/*
  51 * Deliver read data back to initiator.
  52 * XXX TBD handle resource problems later.
  53 */
  54int ft_queue_data_in(struct se_cmd *se_cmd)
  55{
  56        struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
  57        struct fc_frame *fp = NULL;
  58        struct fc_exch *ep;
  59        struct fc_lport *lport;
  60        struct scatterlist *sg = NULL;
  61        size_t remaining;
  62        u32 f_ctl = FC_FC_EX_CTX | FC_FC_REL_OFF;
  63        u32 mem_off = 0;
  64        u32 fh_off = 0;
  65        u32 frame_off = 0;
  66        size_t frame_len = 0;
  67        size_t mem_len = 0;
  68        size_t tlen;
  69        size_t off_in_page;
  70        struct page *page = NULL;
  71        int use_sg;
  72        int error;
  73        void *page_addr;
  74        void *from;
  75        void *to = NULL;
  76
  77        if (cmd->aborted)
  78                return 0;
  79
  80        if (se_cmd->scsi_status == SAM_STAT_TASK_SET_FULL)
  81                goto queue_status;
  82
  83        ep = fc_seq_exch(cmd->seq);
  84        lport = ep->lp;
  85        cmd->seq = fc_seq_start_next(cmd->seq);
  86
  87        remaining = se_cmd->data_length;
  88
  89        /*
  90         * Setup to use first mem list entry, unless no data.
  91         */
  92        BUG_ON(remaining && !se_cmd->t_data_sg);
  93        if (remaining) {
  94                sg = se_cmd->t_data_sg;
  95                mem_len = sg->length;
  96                mem_off = sg->offset;
  97                page = sg_page(sg);
  98        }
  99
 100        /* no scatter/gather in skb for odd word length due to fc_seq_send() */
 101        use_sg = !(remaining % 4);
 102
 103        while (remaining) {
 104                struct fc_seq *seq = cmd->seq;
 105
 106                if (!seq) {
 107                        pr_debug("%s: Command aborted, xid 0x%x\n",
 108                                 __func__, ep->xid);
 109                        break;
 110                }
 111                if (!mem_len) {
 112                        sg = sg_next(sg);
 113                        mem_len = min((size_t)sg->length, remaining);
 114                        mem_off = sg->offset;
 115                        page = sg_page(sg);
 116                }
 117                if (!frame_len) {
 118                        /*
 119                         * If lport's has capability of Large Send Offload LSO)
 120                         * , then allow 'frame_len' to be as big as 'lso_max'
 121                         * if indicated transfer length is >= lport->lso_max
 122                         */
 123                        frame_len = (lport->seq_offload) ? lport->lso_max :
 124                                                          cmd->sess->max_frame;
 125                        frame_len = min(frame_len, remaining);
 126                        fp = fc_frame_alloc(lport, use_sg ? 0 : frame_len);
 127                        if (!fp)
 128                                return -ENOMEM;
 129                        to = fc_frame_payload_get(fp, 0);
 130                        fh_off = frame_off;
 131                        frame_off += frame_len;
 132                        /*
 133                         * Setup the frame's max payload which is used by base
 134                         * driver to indicate HW about max frame size, so that
 135                         * HW can do fragmentation appropriately based on
 136                         * "gso_max_size" of underline netdev.
 137                         */
 138                        fr_max_payload(fp) = cmd->sess->max_frame;
 139                }
 140                tlen = min(mem_len, frame_len);
 141
 142                if (use_sg) {
 143                        off_in_page = mem_off;
 144                        BUG_ON(!page);
 145                        get_page(page);
 146                        skb_fill_page_desc(fp_skb(fp),
 147                                           skb_shinfo(fp_skb(fp))->nr_frags,
 148                                           page, off_in_page, tlen);
 149                        fr_len(fp) += tlen;
 150                        fp_skb(fp)->data_len += tlen;
 151                        fp_skb(fp)->truesize +=
 152                                        PAGE_SIZE << compound_order(page);
 153                } else {
 154                        BUG_ON(!page);
 155                        from = kmap_atomic(page + (mem_off >> PAGE_SHIFT));
 156                        page_addr = from;
 157                        from += offset_in_page(mem_off);
 158                        tlen = min(tlen, (size_t)(PAGE_SIZE -
 159                                                offset_in_page(mem_off)));
 160                        memcpy(to, from, tlen);
 161                        kunmap_atomic(page_addr);
 162                        to += tlen;
 163                }
 164
 165                mem_off += tlen;
 166                mem_len -= tlen;
 167                frame_len -= tlen;
 168                remaining -= tlen;
 169
 170                if (frame_len &&
 171                    (skb_shinfo(fp_skb(fp))->nr_frags < FC_FRAME_SG_LEN))
 172                        continue;
 173                if (!remaining)
 174                        f_ctl |= FC_FC_END_SEQ;
 175                fc_fill_fc_hdr(fp, FC_RCTL_DD_SOL_DATA, ep->did, ep->sid,
 176                               FC_TYPE_FCP, f_ctl, fh_off);
 177                error = fc_seq_send(lport, seq, fp);
 178                if (error) {
 179                        pr_info_ratelimited("%s: Failed to send frame %p, "
 180                                                "xid <0x%x>, remaining %zu, "
 181                                                "lso_max <0x%x>\n",
 182                                                __func__, fp, ep->xid,
 183                                                remaining, lport->lso_max);
 184                        /*
 185                         * Go ahead and set TASK_SET_FULL status ignoring the
 186                         * rest of the DataIN, and immediately attempt to
 187                         * send the response via ft_queue_status() in order
 188                         * to notify the initiator that it should reduce it's
 189                         * per LUN queue_depth.
 190                         */
 191                        se_cmd->scsi_status = SAM_STAT_TASK_SET_FULL;
 192                        break;
 193                }
 194        }
 195queue_status:
 196        return ft_queue_status(se_cmd);
 197}
 198
 199static void ft_execute_work(struct work_struct *work)
 200{
 201        struct ft_cmd *cmd = container_of(work, struct ft_cmd, work);
 202
 203        target_execute_cmd(&cmd->se_cmd);
 204}
 205
 206/*
 207 * Receive write data frame.
 208 */
 209void ft_recv_write_data(struct ft_cmd *cmd, struct fc_frame *fp)
 210{
 211        struct se_cmd *se_cmd = &cmd->se_cmd;
 212        struct fc_seq *seq = cmd->seq;
 213        struct fc_exch *ep;
 214        struct fc_lport *lport;
 215        struct fc_frame_header *fh;
 216        struct scatterlist *sg = NULL;
 217        u32 mem_off = 0;
 218        u32 rel_off;
 219        size_t frame_len;
 220        size_t mem_len = 0;
 221        size_t tlen;
 222        struct page *page = NULL;
 223        void *page_addr;
 224        void *from;
 225        void *to;
 226        u32 f_ctl;
 227        void *buf;
 228
 229        fh = fc_frame_header_get(fp);
 230        if (!(ntoh24(fh->fh_f_ctl) & FC_FC_REL_OFF))
 231                goto drop;
 232
 233        f_ctl = ntoh24(fh->fh_f_ctl);
 234        ep = fc_seq_exch(seq);
 235        lport = ep->lp;
 236        if (cmd->was_ddp_setup) {
 237                BUG_ON(!ep);
 238                BUG_ON(!lport);
 239                /*
 240                 * Since DDP (Large Rx offload) was setup for this request,
 241                 * payload is expected to be copied directly to user buffers.
 242                 */
 243                buf = fc_frame_payload_get(fp, 1);
 244                if (buf)
 245                        pr_err("%s: xid 0x%x, f_ctl 0x%x, cmd->sg %p, "
 246                                "cmd->sg_cnt 0x%x. DDP was setup"
 247                                " hence not expected to receive frame with "
 248                                "payload, Frame will be dropped if"
 249                                "'Sequence Initiative' bit in f_ctl is"
 250                                "not set\n", __func__, ep->xid, f_ctl,
 251                                se_cmd->t_data_sg, se_cmd->t_data_nents);
 252                /*
 253                 * Invalidate HW DDP context if it was setup for respective
 254                 * command. Invalidation of HW DDP context is requited in both
 255                 * situation (success and error).
 256                 */
 257                ft_invl_hw_context(cmd);
 258
 259                /*
 260                 * If "Sequence Initiative (TSI)" bit set in f_ctl, means last
 261                 * write data frame is received successfully where payload is
 262                 * posted directly to user buffer and only the last frame's
 263                 * header is posted in receive queue.
 264                 *
 265                 * If "Sequence Initiative (TSI)" bit is not set, means error
 266                 * condition w.r.t. DDP, hence drop the packet and let explict
 267                 * ABORTS from other end of exchange timer trigger the recovery.
 268                 */
 269                if (f_ctl & FC_FC_SEQ_INIT)
 270                        goto last_frame;
 271                else
 272                        goto drop;
 273        }
 274
 275        rel_off = ntohl(fh->fh_parm_offset);
 276        frame_len = fr_len(fp);
 277        if (frame_len <= sizeof(*fh))
 278                goto drop;
 279        frame_len -= sizeof(*fh);
 280        from = fc_frame_payload_get(fp, 0);
 281        if (rel_off >= se_cmd->data_length)
 282                goto drop;
 283        if (frame_len + rel_off > se_cmd->data_length)
 284                frame_len = se_cmd->data_length - rel_off;
 285
 286        /*
 287         * Setup to use first mem list entry, unless no data.
 288         */
 289        BUG_ON(frame_len && !se_cmd->t_data_sg);
 290        if (frame_len) {
 291                sg = se_cmd->t_data_sg;
 292                mem_len = sg->length;
 293                mem_off = sg->offset;
 294                page = sg_page(sg);
 295        }
 296
 297        while (frame_len) {
 298                if (!mem_len) {
 299                        sg = sg_next(sg);
 300                        mem_len = sg->length;
 301                        mem_off = sg->offset;
 302                        page = sg_page(sg);
 303                }
 304                if (rel_off >= mem_len) {
 305                        rel_off -= mem_len;
 306                        mem_len = 0;
 307                        continue;
 308                }
 309                mem_off += rel_off;
 310                mem_len -= rel_off;
 311                rel_off = 0;
 312
 313                tlen = min(mem_len, frame_len);
 314
 315                to = kmap_atomic(page + (mem_off >> PAGE_SHIFT));
 316                page_addr = to;
 317                to += offset_in_page(mem_off);
 318                tlen = min(tlen, (size_t)(PAGE_SIZE -
 319                                          offset_in_page(mem_off)));
 320                memcpy(to, from, tlen);
 321                kunmap_atomic(page_addr);
 322
 323                from += tlen;
 324                frame_len -= tlen;
 325                mem_off += tlen;
 326                mem_len -= tlen;
 327                cmd->write_data_len += tlen;
 328        }
 329last_frame:
 330        if (cmd->write_data_len == se_cmd->data_length) {
 331                INIT_WORK(&cmd->work, ft_execute_work);
 332                queue_work(cmd->sess->tport->tpg->workqueue, &cmd->work);
 333        }
 334drop:
 335        fc_frame_free(fp);
 336}
 337
 338/*
 339 * Handle and cleanup any HW specific resources if
 340 * received ABORTS, errors, timeouts.
 341 */
 342void ft_invl_hw_context(struct ft_cmd *cmd)
 343{
 344        struct fc_seq *seq;
 345        struct fc_exch *ep = NULL;
 346        struct fc_lport *lport = NULL;
 347
 348        BUG_ON(!cmd);
 349        seq = cmd->seq;
 350
 351        /* Cleanup the DDP context in HW if DDP was setup */
 352        if (cmd->was_ddp_setup && seq) {
 353                ep = fc_seq_exch(seq);
 354                if (ep) {
 355                        lport = ep->lp;
 356                        if (lport && (ep->xid <= lport->lro_xid)) {
 357                                /*
 358                                 * "ddp_done" trigger invalidation of HW
 359                                 * specific DDP context
 360                                 */
 361                                cmd->write_data_len = lport->tt.ddp_done(lport,
 362                                                                      ep->xid);
 363
 364                                /*
 365                                 * Resetting same variable to indicate HW's
 366                                 * DDP context has been invalidated to avoid
 367                                 * re_invalidation of same context (context is
 368                                 * identified using ep->xid)
 369                                 */
 370                                cmd->was_ddp_setup = 0;
 371                        }
 372                }
 373        }
 374}
 375