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