drivers/scsi/ibmvscsi_tgt/libsrp.c

   1 /*******************************************************************************
   2  * SCSI RDMA Protocol lib functions
   3  *
   4  * Copyright (C) 2006 FUJITA Tomonori <tomof@acm.org>
   5  * Copyright (C) 2016 Bryant G. Ly <bryantly@linux.vnet.ibm.com> IBM Corp.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  ***********************************************************************/
  18
  19 #define pr_fmt(fmt)     "libsrp: " fmt
  20
  21 #include <linux/printk.h>
  22 #include <linux/err.h>
  23 #include <linux/slab.h>
  24 #include <linux/kfifo.h>
  25 #include <linux/scatterlist.h>
  26 #include <linux/dma-mapping.h>
  27 #include <linux/module.h>
  28 #include <scsi/srp.h>
  29 #include <target/target_core_base.h>
  30 #include "libsrp.h"
  31 #include "ibmvscsi_tgt.h"
  32
  33 static int srp_iu_pool_alloc(struct srp_queue *q, size_t max,
  34                              struct srp_buf **ring)
  35 {
  36         struct iu_entry *iue;
  37         int i;
  38
  39         q->pool = kcalloc(max, sizeof(struct iu_entry *), GFP_KERNEL);
  40         if (!q->pool)
  41                 return -ENOMEM;
  42         q->items = kcalloc(max, sizeof(struct iu_entry), GFP_KERNEL);
  43         if (!q->items)
  44                 goto free_pool;
  45
  46         spin_lock_init(&q->lock);
  47         kfifo_init(&q->queue, (void *)q->pool, max * sizeof(void *));
  48
  49         for (i = 0, iue = q->items; i < max; i++) {
  50                 kfifo_in(&q->queue, (void *)&iue, sizeof(void *));
  51                 iue->sbuf = ring[i];
  52                 iue++;
  53         }
  54         return 0;
  55
  56 free_pool:
  57         kfree(q->pool);
  58         return -ENOMEM;
  59 }
  60
  61 static void srp_iu_pool_free(struct srp_queue *q)
  62 {
  63         kfree(q->items);
  64         kfree(q->pool);
  65 }
  66
  67 static struct srp_buf **srp_ring_alloc(struct device *dev,
  68                                        size_t max, size_t size)
  69 {
  70         struct srp_buf **ring;
  71         int i;
  72
  73         ring = kcalloc(max, sizeof(struct srp_buf *), GFP_KERNEL);
  74         if (!ring)
  75                 return NULL;
  76
  77         for (i = 0; i < max; i++) {
  78                 ring[i] = kzalloc(sizeof(*ring[i]), GFP_KERNEL);
  79                 if (!ring[i])
  80                         goto out;
  81                 ring[i]->buf = dma_alloc_coherent(dev, size, &ring[i]->dma,
  82                                                   GFP_KERNEL);
  83                 if (!ring[i]->buf)
  84                         goto out;
  85         }
  86         return ring;
  87
  88 out:
  89         for (i = 0; i < max && ring[i]; i++) {
  90                 if (ring[i]->buf) {
  91                         dma_free_coherent(dev, size, ring[i]->buf,
  92                                           ring[i]->dma);
  93                 }
  94                 kfree(ring[i]);
  95         }
  96         kfree(ring);
  97
  98         return NULL;
  99 }
 100
 101 static void srp_ring_free(struct device *dev, struct srp_buf **ring,
 102                           size_t max, size_t size)
 103 {
 104         int i;
 105
 106         for (i = 0; i < max; i++) {
 107                 dma_free_coherent(dev, size, ring[i]->buf, ring[i]->dma);
 108                 kfree(ring[i]);
 109         }
 110         kfree(ring);
 111 }
 112
 113 int srp_target_alloc(struct srp_target *target, struct device *dev,
 114                      size_t nr, size_t iu_size)
 115 {
 116         int err;
 117
 118         spin_lock_init(&target->lock);
 119
 120         target->dev = dev;
 121
 122         target->srp_iu_size = iu_size;
 123         target->rx_ring_size = nr;
 124         target->rx_ring = srp_ring_alloc(target->dev, nr, iu_size);
 125         if (!target->rx_ring)
 126                 return -ENOMEM;
 127         err = srp_iu_pool_alloc(&target->iu_queue, nr, target->rx_ring);
 128         if (err)
 129                 goto free_ring;
 130
 131         dev_set_drvdata(target->dev, target);
 132         return 0;
 133
 134 free_ring:
 135         srp_ring_free(target->dev, target->rx_ring, nr, iu_size);
 136         return -ENOMEM;
 137 }
 138
 139 void srp_target_free(struct srp_target *target)
 140 {
 141         dev_set_drvdata(target->dev, NULL);
 142         srp_ring_free(target->dev, target->rx_ring, target->rx_ring_size,
 143                       target->srp_iu_size);
 144         srp_iu_pool_free(&target->iu_queue);
 145 }
 146
 147 struct iu_entry *srp_iu_get(struct srp_target *target)
 148 {
 149         struct iu_entry *iue = NULL;
 150
 151         if (kfifo_out_locked(&target->iu_queue.queue, (void *)&iue,
 152                              sizeof(void *),
 153                              &target->iu_queue.lock) != sizeof(void *)) {
 154                 WARN_ONCE(1, "unexpected fifo state");
 155                 return NULL;
 156         }
 157         if (!iue)
 158                 return iue;
 159         iue->target = target;
 160         iue->flags = 0;
 161         return iue;
 162 }
 163
 164 void srp_iu_put(struct iu_entry *iue)
 165 {
 166         kfifo_in_locked(&iue->target->iu_queue.queue, (void *)&iue,
 167                         sizeof(void *), &iue->target->iu_queue.lock);
 168 }
 169
 170 static int srp_direct_data(struct ibmvscsis_cmd *cmd, struct srp_direct_buf *md,
 171                            enum dma_data_direction dir, srp_rdma_t rdma_io,
 172                            int dma_map, int ext_desc)
 173 {
 174         struct iu_entry *iue = NULL;
 175         struct scatterlist *sg = NULL;
 176         int err, nsg = 0, len;
 177
 178         if (dma_map) {
 179                 iue = cmd->iue;
 180                 sg = cmd->se_cmd.t_data_sg;
 181                 nsg = dma_map_sg(iue->target->dev, sg, cmd->se_cmd.t_data_nents,
 182                                  DMA_BIDIRECTIONAL);
 183                 if (!nsg) {
 184                         pr_err("fail to map %p %d\n", iue,
 185                                cmd->se_cmd.t_data_nents);
 186                         return 0;
 187                 }
 188                 len = min(cmd->se_cmd.data_length, be32_to_cpu(md->len));
 189         } else {
 190                 len = be32_to_cpu(md->len);
 191         }
 192
 193         err = rdma_io(cmd, sg, nsg, md, 1, dir, len);
 194
 195         if (dma_map)
 196                 dma_unmap_sg(iue->target->dev, sg, nsg, DMA_BIDIRECTIONAL);
 197
 198         return err;
 199 }
 200
 201 static int srp_indirect_data(struct ibmvscsis_cmd *cmd, struct srp_cmd *srp_cmd,
 202                              struct srp_indirect_buf *id,
 203                              enum dma_data_direction dir, srp_rdma_t rdma_io,
 204                              int dma_map, int ext_desc)
 205 {
 206         struct iu_entry *iue = NULL;
 207         struct srp_direct_buf *md = NULL;
 208         struct scatterlist dummy, *sg = NULL;
 209         dma_addr_t token = 0;
 210         int err = 0;
 211         int nmd, nsg = 0, len;
 212
 213         if (dma_map || ext_desc) {
 214                 iue = cmd->iue;
 215                 sg = cmd->se_cmd.t_data_sg;
 216         }
 217
 218         nmd = be32_to_cpu(id->table_desc.len) / sizeof(struct srp_direct_buf);
 219
 220         if ((dir == DMA_FROM_DEVICE && nmd == srp_cmd->data_in_desc_cnt) ||
 221             (dir == DMA_TO_DEVICE && nmd == srp_cmd->data_out_desc_cnt)) {
 222                 md = &id->desc_list[0];
 223                 goto rdma;
 224         }
 225
 226         if (ext_desc && dma_map) {
 227                 md = dma_alloc_coherent(iue->target->dev,
 228                                         be32_to_cpu(id->table_desc.len),
 229                                         &token, GFP_KERNEL);
 230                 if (!md) {
 231                         pr_err("Can't get dma memory %u\n",
 232                                be32_to_cpu(id->table_desc.len));
 233                         return -ENOMEM;
 234                 }
 235
 236                 sg_init_one(&dummy, md, be32_to_cpu(id->table_desc.len));
 237                 sg_dma_address(&dummy) = token;
 238                 sg_dma_len(&dummy) = be32_to_cpu(id->table_desc.len);
 239                 err = rdma_io(cmd, &dummy, 1, &id->table_desc, 1, DMA_TO_DEVICE,
 240                               be32_to_cpu(id->table_desc.len));
 241                 if (err) {
 242                         pr_err("Error copying indirect table %d\n", err);
 243                         goto free_mem;
 244                 }
 245         } else {
 246                 pr_err("This command uses external indirect buffer\n");
 247                 return -EINVAL;
 248         }
 249
 250 rdma:
 251         if (dma_map) {
 252                 nsg = dma_map_sg(iue->target->dev, sg, cmd->se_cmd.t_data_nents,
 253                                  DMA_BIDIRECTIONAL);
 254                 if (!nsg) {
 255                         pr_err("fail to map %p %d\n", iue,
 256                                cmd->se_cmd.t_data_nents);
 257                         err = -EIO;
 258                         goto free_mem;
 259                 }
 260                 len = min(cmd->se_cmd.data_length, be32_to_cpu(id->len));
 261         } else {
 262                 len = be32_to_cpu(id->len);
 263         }
 264
 265         err = rdma_io(cmd, sg, nsg, md, nmd, dir, len);
 266
 267         if (dma_map)
 268                 dma_unmap_sg(iue->target->dev, sg, nsg, DMA_BIDIRECTIONAL);
 269
 270 free_mem:
 271         if (token && dma_map) {
 272                 dma_free_coherent(iue->target->dev,
 273                                   be32_to_cpu(id->table_desc.len), md, token);
 274         }
 275         return err;
 276 }
 277
 278 static int data_out_desc_size(struct srp_cmd *cmd)
 279 {
 280         int size = 0;
 281         u8 fmt = cmd->buf_fmt >> 4;
 282
 283         switch (fmt) {
 284         case SRP_NO_DATA_DESC:
 285                 break;
 286         case SRP_DATA_DESC_DIRECT:
 287                 size = sizeof(struct srp_direct_buf);
 288                 break;
 289         case SRP_DATA_DESC_INDIRECT:
 290                 size = sizeof(struct srp_indirect_buf) +
 291                         sizeof(struct srp_direct_buf) * cmd->data_out_desc_cnt;
 292                 break;
 293         default:
 294                 pr_err("client error. Invalid data_out_format %x\n", fmt);
 295                 break;
 296         }
 297         return size;
 298 }
 299
 300 /*
 301  * TODO: this can be called multiple times for a single command if it
 302  * has very long data.
 303  */
 304 int srp_transfer_data(struct ibmvscsis_cmd *cmd, struct srp_cmd *srp_cmd,
 305                       srp_rdma_t rdma_io, int dma_map, int ext_desc)
 306 {
 307         struct srp_direct_buf *md;
 308         struct srp_indirect_buf *id;
 309         enum dma_data_direction dir;
 310         int offset, err = 0;
 311         u8 format;
 312
 313         if (!cmd->se_cmd.t_data_nents)
 314                 return 0;
 315
 316         offset = srp_cmd->add_cdb_len & ~3;
 317
 318         dir = srp_cmd_direction(srp_cmd);
 319         if (dir == DMA_FROM_DEVICE)
 320                 offset += data_out_desc_size(srp_cmd);
 321
 322         if (dir == DMA_TO_DEVICE)
 323                 format = srp_cmd->buf_fmt >> 4;
 324         else
 325                 format = srp_cmd->buf_fmt & ((1U << 4) - 1);
 326
 327         switch (format) {
 328         case SRP_NO_DATA_DESC:
 329                 break;
 330         case SRP_DATA_DESC_DIRECT:
 331                 md = (struct srp_direct_buf *)(srp_cmd->add_data + offset);
 332                 err = srp_direct_data(cmd, md, dir, rdma_io, dma_map, ext_desc);
 333                 break;
 334         case SRP_DATA_DESC_INDIRECT:
 335                 id = (struct srp_indirect_buf *)(srp_cmd->add_data + offset);
 336                 err = srp_indirect_data(cmd, srp_cmd, id, dir, rdma_io, dma_map,
 337                                         ext_desc);
 338                 break;
 339         default:
 340                 pr_err("Unknown format %d %x\n", dir, format);
 341                 err = -EINVAL;
 342         }
 343
 344         return err;
 345 }
 346
 347 u64 srp_data_length(struct srp_cmd *cmd, enum dma_data_direction dir)
 348 {
 349         struct srp_direct_buf *md;
 350         struct srp_indirect_buf *id;
 351         u64 len = 0;
 352         uint offset = cmd->add_cdb_len & ~3;
 353         u8 fmt;
 354
 355         if (dir == DMA_TO_DEVICE) {
 356                 fmt = cmd->buf_fmt >> 4;
 357         } else {
 358                 fmt = cmd->buf_fmt & ((1U << 4) - 1);
 359                 offset += data_out_desc_size(cmd);
 360         }
 361
 362         switch (fmt) {
 363         case SRP_NO_DATA_DESC:
 364                 break;
 365         case SRP_DATA_DESC_DIRECT:
 366                 md = (struct srp_direct_buf *)(cmd->add_data + offset);
 367                 len = be32_to_cpu(md->len);
 368                 break;
 369         case SRP_DATA_DESC_INDIRECT:
 370                 id = (struct srp_indirect_buf *)(cmd->add_data + offset);
 371                 len = be32_to_cpu(id->len);
 372                 break;
 373         default:
 374                 pr_err("invalid data format %x\n", fmt);
 375                 break;
 376         }
 377         return len;
 378 }
 379
 380 int srp_get_desc_table(struct srp_cmd *srp_cmd, enum dma_data_direction *dir,
 381                        u64 *data_len)
 382 {
 383         struct srp_indirect_buf *idb;
 384         struct srp_direct_buf *db;
 385         uint add_cdb_offset;
 386         int rc;
 387
 388         /*
 389          * The pointer computations below will only be compiled correctly
 390          * if srp_cmd::add_data is declared as s8*, u8*, s8[] or u8[], so check
 391          * whether srp_cmd::add_data has been declared as a byte pointer.
 392          */
 393         BUILD_BUG_ON(!__same_type(srp_cmd->add_data[0], (s8)0)
 394                      && !__same_type(srp_cmd->add_data[0], (u8)0));
 395
 396         BUG_ON(!dir);
 397         BUG_ON(!data_len);
 398
 399         rc = 0;
 400         *data_len = 0;
 401
 402         *dir = DMA_NONE;
 403
 404         if (srp_cmd->buf_fmt & 0xf)
 405                 *dir = DMA_FROM_DEVICE;
 406         else if (srp_cmd->buf_fmt >> 4)
 407                 *dir = DMA_TO_DEVICE;
 408
 409         add_cdb_offset = srp_cmd->add_cdb_len & ~3;
 410         if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_DIRECT) ||
 411             ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_DIRECT)) {
 412                 db = (struct srp_direct_buf *)(srp_cmd->add_data
 413                                                + add_cdb_offset);
 414                 *data_len = be32_to_cpu(db->len);
 415         } else if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_INDIRECT) ||
 416                    ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_INDIRECT)) {
 417                 idb = (struct srp_indirect_buf *)(srp_cmd->add_data
 418                                                   + add_cdb_offset);
 419
 420                 *data_len = be32_to_cpu(idb->len);
 421         }
 422         return rc;
 423 }
 424
 425 MODULE_DESCRIPTION("SCSI RDMA Protocol lib functions");
 426 MODULE_AUTHOR("FUJITA Tomonori");
 427 MODULE_LICENSE("GPL");