drivers/scsi/libsrp.c

   1 /*
   2  * SCSI RDMA Protocol lib functions
   3  *
   4  * Copyright (C) 2006 FUJITA Tomonori <tomof@acm.org>
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as
   8  * published by the Free Software Foundation; either version 2 of the
   9  * License, or (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  19  * 02110-1301 USA
  20  */
  21 #include <linux/err.h>
  22 #include <linux/kfifo.h>
  23 #include <linux/scatterlist.h>
  24 #include <linux/dma-mapping.h>
  25 #include <scsi/scsi.h>
  26 #include <scsi/scsi_cmnd.h>
  27 #include <scsi/scsi_tcq.h>
  28 #include <scsi/scsi_tgt.h>
  29 #include <scsi/srp.h>
  30 #include <scsi/libsrp.h>
  31
  32 enum srp_task_attributes {
  33         SRP_SIMPLE_TASK = 0,
  34         SRP_HEAD_TASK = 1,
  35         SRP_ORDERED_TASK = 2,
  36         SRP_ACA_TASK = 4
  37 };
  38
  39 /* tmp - will replace with SCSI logging stuff */
  40 #define eprintk(fmt, args...)                                   \
  41 do {                                                            \
  42         printk("%s(%d) " fmt, __func__, __LINE__, ##args);      \
  43 } while (0)
  44 /* #define dprintk eprintk */
  45 #define dprintk(fmt, args...)
  46
  47 static int srp_iu_pool_alloc(struct srp_queue *q, size_t max,
  48                              struct srp_buf **ring)
  49 {
  50         int i;
  51         struct iu_entry *iue;
  52
  53         q->pool = kcalloc(max, sizeof(struct iu_entry *), GFP_KERNEL);
  54         if (!q->pool)
  55                 return -ENOMEM;
  56         q->items = kcalloc(max, sizeof(struct iu_entry), GFP_KERNEL);
  57         if (!q->items)
  58                 goto free_pool;
  59
  60         spin_lock_init(&q->lock);
  61         kfifo_init(&q->queue, (void *) q->pool, max * sizeof(void *));
  62
  63         for (i = 0, iue = q->items; i < max; i++) {
  64                 kfifo_in(&q->queue, (void *) &iue, sizeof(void *));
  65                 iue->sbuf = ring[i];
  66                 iue++;
  67         }
  68         return 0;
  69
  70         kfree(q->items);
  71 free_pool:
  72         kfree(q->pool);
  73         return -ENOMEM;
  74 }
  75
  76 static void srp_iu_pool_free(struct srp_queue *q)
  77 {
  78         kfree(q->items);
  79         kfree(q->pool);
  80 }
  81
  82 static struct srp_buf **srp_ring_alloc(struct device *dev,
  83                                        size_t max, size_t size)
  84 {
  85         int i;
  86         struct srp_buf **ring;
  87
  88         ring = kcalloc(max, sizeof(struct srp_buf *), GFP_KERNEL);
  89         if (!ring)
  90                 return NULL;
  91
  92         for (i = 0; i < max; i++) {
  93                 ring[i] = kzalloc(sizeof(struct srp_buf), GFP_KERNEL);
  94                 if (!ring[i])
  95                         goto out;
  96                 ring[i]->buf = dma_alloc_coherent(dev, size, &ring[i]->dma,
  97                                                   GFP_KERNEL);
  98                 if (!ring[i]->buf)
  99                         goto out;
 100         }
 101         return ring;
 102
 103 out:
 104         for (i = 0; i < max && ring[i]; i++) {
 105                 if (ring[i]->buf)
 106                         dma_free_coherent(dev, size, ring[i]->buf, ring[i]->dma);
 107                 kfree(ring[i]);
 108         }
 109         kfree(ring);
 110
 111         return NULL;
 112 }
 113
 114 static void srp_ring_free(struct device *dev, struct srp_buf **ring, size_t max,
 115                           size_t size)
 116 {
 117         int i;
 118
 119         for (i = 0; i < max; i++) {
 120                 dma_free_coherent(dev, size, ring[i]->buf, ring[i]->dma);
 121                 kfree(ring[i]);
 122         }
 123         kfree(ring);
 124 }
 125
 126 int srp_target_alloc(struct srp_target *target, struct device *dev,
 127                      size_t nr, size_t iu_size)
 128 {
 129         int err;
 130
 131         spin_lock_init(&target->lock);
 132         INIT_LIST_HEAD(&target->cmd_queue);
 133
 134         target->dev = dev;
 135         dev_set_drvdata(target->dev, target);
 136
 137         target->srp_iu_size = iu_size;
 138         target->rx_ring_size = nr;
 139         target->rx_ring = srp_ring_alloc(target->dev, nr, iu_size);
 140         if (!target->rx_ring)
 141                 return -ENOMEM;
 142         err = srp_iu_pool_alloc(&target->iu_queue, nr, target->rx_ring);
 143         if (err)
 144                 goto free_ring;
 145
 146         return 0;
 147
 148 free_ring:
 149         srp_ring_free(target->dev, target->rx_ring, nr, iu_size);
 150         return -ENOMEM;
 151 }
 152 EXPORT_SYMBOL_GPL(srp_target_alloc);
 153
 154 void srp_target_free(struct srp_target *target)
 155 {
 156         srp_ring_free(target->dev, target->rx_ring, target->rx_ring_size,
 157                       target->srp_iu_size);
 158         srp_iu_pool_free(&target->iu_queue);
 159 }
 160 EXPORT_SYMBOL_GPL(srp_target_free);
 161
 162 struct iu_entry *srp_iu_get(struct srp_target *target)
 163 {
 164         struct iu_entry *iue = NULL;
 165
 166         if (kfifo_out_locked(&target->iu_queue.queue, (void *) &iue,
 167                 sizeof(void *), &target->iu_queue.lock) != sizeof(void *)) {
 168                         WARN_ONCE(1, "unexpected fifo state");
 169                         return NULL;
 170         }
 171         if (!iue)
 172                 return iue;
 173         iue->target = target;
 174         INIT_LIST_HEAD(&iue->ilist);
 175         iue->flags = 0;
 176         return iue;
 177 }
 178 EXPORT_SYMBOL_GPL(srp_iu_get);
 179
 180 void srp_iu_put(struct iu_entry *iue)
 181 {
 182         kfifo_in_locked(&iue->target->iu_queue.queue, (void *) &iue,
 183                         sizeof(void *), &iue->target->iu_queue.lock);
 184 }
 185 EXPORT_SYMBOL_GPL(srp_iu_put);
 186
 187 static int srp_direct_data(struct scsi_cmnd *sc, struct srp_direct_buf *md,
 188                            enum dma_data_direction dir, srp_rdma_t rdma_io,
 189                            int dma_map, int ext_desc)
 190 {
 191         struct iu_entry *iue = NULL;
 192         struct scatterlist *sg = NULL;
 193         int err, nsg = 0, len;
 194
 195         if (dma_map) {
 196                 iue = (struct iu_entry *) sc->SCp.ptr;
 197                 sg = scsi_sglist(sc);
 198
 199                 dprintk("%p %u %u %d\n", iue, scsi_bufflen(sc),
 200                         md->len, scsi_sg_count(sc));
 201
 202                 nsg = dma_map_sg(iue->target->dev, sg, scsi_sg_count(sc),
 203                                  DMA_BIDIRECTIONAL);
 204                 if (!nsg) {
 205                         printk("fail to map %p %d\n", iue, scsi_sg_count(sc));
 206                         return 0;
 207                 }
 208                 len = min(scsi_bufflen(sc), md->len);
 209         } else
 210                 len = md->len;
 211
 212         err = rdma_io(sc, sg, nsg, md, 1, dir, len);
 213
 214         if (dma_map)
 215                 dma_unmap_sg(iue->target->dev, sg, nsg, DMA_BIDIRECTIONAL);
 216
 217         return err;
 218 }
 219
 220 static int srp_indirect_data(struct scsi_cmnd *sc, struct srp_cmd *cmd,
 221                              struct srp_indirect_buf *id,
 222                              enum dma_data_direction dir, srp_rdma_t rdma_io,
 223                              int dma_map, int ext_desc)
 224 {
 225         struct iu_entry *iue = NULL;
 226         struct srp_direct_buf *md = NULL;
 227         struct scatterlist dummy, *sg = NULL;
 228         dma_addr_t token = 0;
 229         int err = 0;
 230         int nmd, nsg = 0, len;
 231
 232         if (dma_map || ext_desc) {
 233                 iue = (struct iu_entry *) sc->SCp.ptr;
 234                 sg = scsi_sglist(sc);
 235
 236                 dprintk("%p %u %u %d %d\n",
 237                         iue, scsi_bufflen(sc), id->len,
 238                         cmd->data_in_desc_cnt, cmd->data_out_desc_cnt);
 239         }
 240
 241         nmd = id->table_desc.len / sizeof(struct srp_direct_buf);
 242
 243         if ((dir == DMA_FROM_DEVICE && nmd == cmd->data_in_desc_cnt) ||
 244             (dir == DMA_TO_DEVICE && nmd == cmd->data_out_desc_cnt)) {
 245                 md = &id->desc_list[0];
 246                 goto rdma;
 247         }
 248
 249         if (ext_desc && dma_map) {
 250                 md = dma_alloc_coherent(iue->target->dev, id->table_desc.len,
 251                                 &token, GFP_KERNEL);
 252                 if (!md) {
 253                         eprintk("Can't get dma memory %u\n", id->table_desc.len);
 254                         return -ENOMEM;
 255                 }
 256
 257                 sg_init_one(&dummy, md, id->table_desc.len);
 258                 sg_dma_address(&dummy) = token;
 259                 sg_dma_len(&dummy) = id->table_desc.len;
 260                 err = rdma_io(sc, &dummy, 1, &id->table_desc, 1, DMA_TO_DEVICE,
 261                               id->table_desc.len);
 262                 if (err) {
 263                         eprintk("Error copying indirect table %d\n", err);
 264                         goto free_mem;
 265                 }
 266         } else {
 267                 eprintk("This command uses external indirect buffer\n");
 268                 return -EINVAL;
 269         }
 270
 271 rdma:
 272         if (dma_map) {
 273                 nsg = dma_map_sg(iue->target->dev, sg, scsi_sg_count(sc),
 274                                  DMA_BIDIRECTIONAL);
 275                 if (!nsg) {
 276                         eprintk("fail to map %p %d\n", iue, scsi_sg_count(sc));
 277                         err = -EIO;
 278                         goto free_mem;
 279                 }
 280                 len = min(scsi_bufflen(sc), id->len);
 281         } else
 282                 len = id->len;
 283
 284         err = rdma_io(sc, sg, nsg, md, nmd, dir, len);
 285
 286         if (dma_map)
 287                 dma_unmap_sg(iue->target->dev, sg, nsg, DMA_BIDIRECTIONAL);
 288
 289 free_mem:
 290         if (token && dma_map)
 291                 dma_free_coherent(iue->target->dev, id->table_desc.len, md, token);
 292
 293         return err;
 294 }
 295
 296 static int data_out_desc_size(struct srp_cmd *cmd)
 297 {
 298         int size = 0;
 299         u8 fmt = cmd->buf_fmt >> 4;
 300
 301         switch (fmt) {
 302         case SRP_NO_DATA_DESC:
 303                 break;
 304         case SRP_DATA_DESC_DIRECT:
 305                 size = sizeof(struct srp_direct_buf);
 306                 break;
 307         case SRP_DATA_DESC_INDIRECT:
 308                 size = sizeof(struct srp_indirect_buf) +
 309                         sizeof(struct srp_direct_buf) * cmd->data_out_desc_cnt;
 310                 break;
 311         default:
 312                 eprintk("client error. Invalid data_out_format %x\n", fmt);
 313                 break;
 314         }
 315         return size;
 316 }
 317
 318 /*
 319  * TODO: this can be called multiple times for a single command if it
 320  * has very long data.
 321  */
 322 int srp_transfer_data(struct scsi_cmnd *sc, struct srp_cmd *cmd,
 323                       srp_rdma_t rdma_io, int dma_map, int ext_desc)
 324 {
 325         struct srp_direct_buf *md;
 326         struct srp_indirect_buf *id;
 327         enum dma_data_direction dir;
 328         int offset, err = 0;
 329         u8 format;
 330
 331         offset = cmd->add_cdb_len & ~3;
 332
 333         dir = srp_cmd_direction(cmd);
 334         if (dir == DMA_FROM_DEVICE)
 335                 offset += data_out_desc_size(cmd);
 336
 337         if (dir == DMA_TO_DEVICE)
 338                 format = cmd->buf_fmt >> 4;
 339         else
 340                 format = cmd->buf_fmt & ((1U << 4) - 1);
 341
 342         switch (format) {
 343         case SRP_NO_DATA_DESC:
 344                 break;
 345         case SRP_DATA_DESC_DIRECT:
 346                 md = (struct srp_direct_buf *)
 347                         (cmd->add_data + offset);
 348                 err = srp_direct_data(sc, md, dir, rdma_io, dma_map, ext_desc);
 349                 break;
 350         case SRP_DATA_DESC_INDIRECT:
 351                 id = (struct srp_indirect_buf *)
 352                         (cmd->add_data + offset);
 353                 err = srp_indirect_data(sc, cmd, id, dir, rdma_io, dma_map,
 354                                         ext_desc);
 355                 break;
 356         default:
 357                 eprintk("Unknown format %d %x\n", dir, format);
 358                 err = -EINVAL;
 359         }
 360
 361         return err;
 362 }
 363 EXPORT_SYMBOL_GPL(srp_transfer_data);
 364
 365 static int vscsis_data_length(struct srp_cmd *cmd, enum dma_data_direction dir)
 366 {
 367         struct srp_direct_buf *md;
 368         struct srp_indirect_buf *id;
 369         int len = 0, offset = cmd->add_cdb_len & ~3;
 370         u8 fmt;
 371
 372         if (dir == DMA_TO_DEVICE)
 373                 fmt = cmd->buf_fmt >> 4;
 374         else {
 375                 fmt = cmd->buf_fmt & ((1U << 4) - 1);
 376                 offset += data_out_desc_size(cmd);
 377         }
 378
 379         switch (fmt) {
 380         case SRP_NO_DATA_DESC:
 381                 break;
 382         case SRP_DATA_DESC_DIRECT:
 383                 md = (struct srp_direct_buf *) (cmd->add_data + offset);
 384                 len = md->len;
 385                 break;
 386         case SRP_DATA_DESC_INDIRECT:
 387                 id = (struct srp_indirect_buf *) (cmd->add_data + offset);
 388                 len = id->len;
 389                 break;
 390         default:
 391                 eprintk("invalid data format %x\n", fmt);
 392                 break;
 393         }
 394         return len;
 395 }
 396
 397 int srp_cmd_queue(struct Scsi_Host *shost, struct srp_cmd *cmd, void *info,
 398                   u64 itn_id, u64 addr)
 399 {
 400         enum dma_data_direction dir;
 401         struct scsi_cmnd *sc;
 402         int tag, len, err;
 403
 404         switch (cmd->task_attr) {
 405         case SRP_SIMPLE_TASK:
 406                 tag = MSG_SIMPLE_TAG;
 407                 break;
 408         case SRP_ORDERED_TASK:
 409                 tag = MSG_ORDERED_TAG;
 410                 break;
 411         case SRP_HEAD_TASK:
 412                 tag = MSG_HEAD_TAG;
 413                 break;
 414         default:
 415                 eprintk("Task attribute %d not supported\n", cmd->task_attr);
 416                 tag = MSG_ORDERED_TAG;
 417         }
 418
 419         dir = srp_cmd_direction(cmd);
 420         len = vscsis_data_length(cmd, dir);
 421
 422         dprintk("%p %x %lx %d %d %d %llx\n", info, cmd->cdb[0],
 423                 cmd->lun, dir, len, tag, (unsigned long long) cmd->tag);
 424
 425         sc = scsi_host_get_command(shost, dir, GFP_KERNEL);
 426         if (!sc)
 427                 return -ENOMEM;
 428
 429         sc->SCp.ptr = info;
 430         memcpy(sc->cmnd, cmd->cdb, MAX_COMMAND_SIZE);
 431         sc->sdb.length = len;
 432         sc->sdb.table.sgl = (void *) (unsigned long) addr;
 433         sc->tag = tag;
 434         err = scsi_tgt_queue_command(sc, itn_id, (struct scsi_lun *)&cmd->lun,
 435                                      cmd->tag);
 436         if (err)
 437                 scsi_host_put_command(shost, sc);
 438
 439         return err;
 440 }
 441 EXPORT_SYMBOL_GPL(srp_cmd_queue);
 442
 443 MODULE_DESCRIPTION("SCSI RDMA Protocol lib functions");
 444 MODULE_AUTHOR("FUJITA Tomonori");
 445 MODULE_LICENSE("GPL");