drivers/scsi/ibmvscsi_tgt/libsrp.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*******************************************************************************
   3  * SCSI RDMA Protocol lib functions
   4  *
   5  * Copyright (C) 2006 FUJITA Tomonori <tomof@acm.org>
   6  * Copyright (C) 2016 Bryant G. Ly <bryantly@linux.vnet.ibm.com> IBM Corp.
   7  *
   8  ***********************************************************************/
   9
  10 #define pr_fmt(fmt)     "libsrp: " fmt
  11
  12 #include <linux/printk.h>
  13 #include <linux/err.h>
  14 #include <linux/slab.h>
  15 #include <linux/kfifo.h>
  16 #include <linux/scatterlist.h>
  17 #include <linux/dma-mapping.h>
  18 #include <linux/module.h>
  19 #include <scsi/srp.h>
  20 #include <target/target_core_base.h>
  21 #include "libsrp.h"
  22 #include "ibmvscsi_tgt.h"
  23
  24 static int srp_iu_pool_alloc(struct srp_queue *q, size_t max,
  25                              struct srp_buf **ring)
  26 {
  27         struct iu_entry *iue;
  28         int i;
  29
  30         q->pool = kcalloc(max, sizeof(struct iu_entry *), GFP_KERNEL);
  31         if (!q->pool)
  32                 return -ENOMEM;
  33         q->items = kcalloc(max, sizeof(struct iu_entry), GFP_KERNEL);
  34         if (!q->items)
  35                 goto free_pool;
  36
  37         spin_lock_init(&q->lock);
  38         kfifo_init(&q->queue, (void *)q->pool, max * sizeof(void *));
  39
  40         for (i = 0, iue = q->items; i < max; i++) {
  41                 kfifo_in(&q->queue, (void *)&iue, sizeof(void *));
  42                 iue->sbuf = ring[i];
  43                 iue++;
  44         }
  45         return 0;
  46
  47 free_pool:
  48         kfree(q->pool);
  49         return -ENOMEM;
  50 }
  51
  52 static void srp_iu_pool_free(struct srp_queue *q)
  53 {
  54         kfree(q->items);
  55         kfree(q->pool);
  56 }
  57
  58 static struct srp_buf **srp_ring_alloc(struct device *dev,
  59                                        size_t max, size_t size)
  60 {
  61         struct srp_buf **ring;
  62         int i;
  63
  64         ring = kcalloc(max, sizeof(struct srp_buf *), GFP_KERNEL);
  65         if (!ring)
  66                 return NULL;
  67
  68         for (i = 0; i < max; i++) {
  69                 ring[i] = kzalloc(sizeof(*ring[i]), GFP_KERNEL);
  70                 if (!ring[i])
  71                         goto out;
  72                 ring[i]->buf = dma_alloc_coherent(dev, size, &ring[i]->dma,
  73                                                   GFP_KERNEL);
  74                 if (!ring[i]->buf)
  75                         goto out;
  76         }
  77         return ring;
  78
  79 out:
  80         for (i = 0; i < max && ring[i]; i++) {
  81                 if (ring[i]->buf) {
  82                         dma_free_coherent(dev, size, ring[i]->buf,
  83                                           ring[i]->dma);
  84                 }
  85                 kfree(ring[i]);
  86         }
  87         kfree(ring);
  88
  89         return NULL;
  90 }
  91
  92 static void srp_ring_free(struct device *dev, struct srp_buf **ring,
  93                           size_t max, size_t size)
  94 {
  95         int i;
  96
  97         for (i = 0; i < max; i++) {
  98                 dma_free_coherent(dev, size, ring[i]->buf, ring[i]->dma);
  99                 kfree(ring[i]);
 100         }
 101         kfree(ring);
 102 }
 103
 104 int srp_target_alloc(struct srp_target *target, struct device *dev,
 105                      size_t nr, size_t iu_size)
 106 {
 107         int err;
 108
 109         spin_lock_init(&target->lock);
 110
 111         target->dev = dev;
 112
 113         target->srp_iu_size = iu_size;
 114         target->rx_ring_size = nr;
 115         target->rx_ring = srp_ring_alloc(target->dev, nr, iu_size);
 116         if (!target->rx_ring)
 117                 return -ENOMEM;
 118         err = srp_iu_pool_alloc(&target->iu_queue, nr, target->rx_ring);
 119         if (err)
 120                 goto free_ring;
 121
 122         dev_set_drvdata(target->dev, target);
 123         return 0;
 124
 125 free_ring:
 126         srp_ring_free(target->dev, target->rx_ring, nr, iu_size);
 127         return -ENOMEM;
 128 }
 129
 130 void srp_target_free(struct srp_target *target)
 131 {
 132         dev_set_drvdata(target->dev, NULL);
 133         srp_ring_free(target->dev, target->rx_ring, target->rx_ring_size,
 134                       target->srp_iu_size);
 135         srp_iu_pool_free(&target->iu_queue);
 136 }
 137
 138 struct iu_entry *srp_iu_get(struct srp_target *target)
 139 {
 140         struct iu_entry *iue = NULL;
 141
 142         if (kfifo_out_locked(&target->iu_queue.queue, (void *)&iue,
 143                              sizeof(void *),
 144                              &target->iu_queue.lock) != sizeof(void *)) {
 145                 WARN_ONCE(1, "unexpected fifo state");
 146                 return NULL;
 147         }
 148         if (!iue)
 149                 return iue;
 150         iue->target = target;
 151         iue->flags = 0;
 152         return iue;
 153 }
 154
 155 void srp_iu_put(struct iu_entry *iue)
 156 {
 157         kfifo_in_locked(&iue->target->iu_queue.queue, (void *)&iue,
 158                         sizeof(void *), &iue->target->iu_queue.lock);
 159 }
 160
 161 static int srp_direct_data(struct ibmvscsis_cmd *cmd, struct srp_direct_buf *md,
 162                            enum dma_data_direction dir, srp_rdma_t rdma_io,
 163                            int dma_map, int ext_desc)
 164 {
 165         struct iu_entry *iue = NULL;
 166         struct scatterlist *sg = NULL;
 167         int err, nsg = 0, len;
 168
 169         if (dma_map) {
 170                 iue = cmd->iue;
 171                 sg = cmd->se_cmd.t_data_sg;
 172                 nsg = dma_map_sg(iue->target->dev, sg, cmd->se_cmd.t_data_nents,
 173                                  DMA_BIDIRECTIONAL);
 174                 if (!nsg) {
 175                         pr_err("fail to map %p %d\n", iue,
 176                                cmd->se_cmd.t_data_nents);
 177                         return 0;
 178                 }
 179                 len = min(cmd->se_cmd.data_length, be32_to_cpu(md->len));
 180         } else {
 181                 len = be32_to_cpu(md->len);
 182         }
 183
 184         err = rdma_io(cmd, sg, nsg, md, 1, dir, len);
 185
 186         if (dma_map)
 187                 dma_unmap_sg(iue->target->dev, sg, nsg, DMA_BIDIRECTIONAL);
 188
 189         return err;
 190 }
 191
 192 static int srp_indirect_data(struct ibmvscsis_cmd *cmd, struct srp_cmd *srp_cmd,
 193                              struct srp_indirect_buf *id,
 194                              enum dma_data_direction dir, srp_rdma_t rdma_io,
 195                              int dma_map, int ext_desc)
 196 {
 197         struct iu_entry *iue = NULL;
 198         struct srp_direct_buf *md = NULL;
 199         struct scatterlist dummy, *sg = NULL;
 200         dma_addr_t token = 0;
 201         int err = 0;
 202         int nmd, nsg = 0, len;
 203
 204         if (dma_map || ext_desc) {
 205                 iue = cmd->iue;
 206                 sg = cmd->se_cmd.t_data_sg;
 207         }
 208
 209         nmd = be32_to_cpu(id->table_desc.len) / sizeof(struct srp_direct_buf);
 210
 211         if ((dir == DMA_FROM_DEVICE && nmd == srp_cmd->data_in_desc_cnt) ||
 212             (dir == DMA_TO_DEVICE && nmd == srp_cmd->data_out_desc_cnt)) {
 213                 md = &id->desc_list[0];
 214                 goto rdma;
 215         }
 216
 217         if (ext_desc && dma_map) {
 218                 md = dma_alloc_coherent(iue->target->dev,
 219                                         be32_to_cpu(id->table_desc.len),
 220                                         &token, GFP_KERNEL);
 221                 if (!md) {
 222                         pr_err("Can't get dma memory %u\n",
 223                                be32_to_cpu(id->table_desc.len));
 224                         return -ENOMEM;
 225                 }
 226
 227                 sg_init_one(&dummy, md, be32_to_cpu(id->table_desc.len));
 228                 sg_dma_address(&dummy) = token;
 229                 sg_dma_len(&dummy) = be32_to_cpu(id->table_desc.len);
 230                 err = rdma_io(cmd, &dummy, 1, &id->table_desc, 1, DMA_TO_DEVICE,
 231                               be32_to_cpu(id->table_desc.len));
 232                 if (err) {
 233                         pr_err("Error copying indirect table %d\n", err);
 234                         goto free_mem;
 235                 }
 236         } else {
 237                 pr_err("This command uses external indirect buffer\n");
 238                 return -EINVAL;
 239         }
 240
 241 rdma:
 242         if (dma_map) {
 243                 nsg = dma_map_sg(iue->target->dev, sg, cmd->se_cmd.t_data_nents,
 244                                  DMA_BIDIRECTIONAL);
 245                 if (!nsg) {
 246                         pr_err("fail to map %p %d\n", iue,
 247                                cmd->se_cmd.t_data_nents);
 248                         err = -EIO;
 249                         goto free_mem;
 250                 }
 251                 len = min(cmd->se_cmd.data_length, be32_to_cpu(id->len));
 252         } else {
 253                 len = be32_to_cpu(id->len);
 254         }
 255
 256         err = rdma_io(cmd, sg, nsg, md, nmd, dir, len);
 257
 258         if (dma_map)
 259                 dma_unmap_sg(iue->target->dev, sg, nsg, DMA_BIDIRECTIONAL);
 260
 261 free_mem:
 262         if (token && dma_map) {
 263                 dma_free_coherent(iue->target->dev,
 264                                   be32_to_cpu(id->table_desc.len), md, token);
 265         }
 266         return err;
 267 }
 268
 269 static int data_out_desc_size(struct srp_cmd *cmd)
 270 {
 271         int size = 0;
 272         u8 fmt = cmd->buf_fmt >> 4;
 273
 274         switch (fmt) {
 275         case SRP_NO_DATA_DESC:
 276                 break;
 277         case SRP_DATA_DESC_DIRECT:
 278                 size = sizeof(struct srp_direct_buf);
 279                 break;
 280         case SRP_DATA_DESC_INDIRECT:
 281                 size = sizeof(struct srp_indirect_buf) +
 282                         sizeof(struct srp_direct_buf) * cmd->data_out_desc_cnt;
 283                 break;
 284         default:
 285                 pr_err("client error. Invalid data_out_format %x\n", fmt);
 286                 break;
 287         }
 288         return size;
 289 }
 290
 291 /*
 292  * TODO: this can be called multiple times for a single command if it
 293  * has very long data.
 294  */
 295 int srp_transfer_data(struct ibmvscsis_cmd *cmd, struct srp_cmd *srp_cmd,
 296                       srp_rdma_t rdma_io, int dma_map, int ext_desc)
 297 {
 298         struct srp_direct_buf *md;
 299         struct srp_indirect_buf *id;
 300         enum dma_data_direction dir;
 301         int offset, err = 0;
 302         u8 format;
 303
 304         if (!cmd->se_cmd.t_data_nents)
 305                 return 0;
 306
 307         offset = srp_cmd->add_cdb_len & ~3;
 308
 309         dir = srp_cmd_direction(srp_cmd);
 310         if (dir == DMA_FROM_DEVICE)
 311                 offset += data_out_desc_size(srp_cmd);
 312
 313         if (dir == DMA_TO_DEVICE)
 314                 format = srp_cmd->buf_fmt >> 4;
 315         else
 316                 format = srp_cmd->buf_fmt & ((1U << 4) - 1);
 317
 318         switch (format) {
 319         case SRP_NO_DATA_DESC:
 320                 break;
 321         case SRP_DATA_DESC_DIRECT:
 322                 md = (struct srp_direct_buf *)(srp_cmd->add_data + offset);
 323                 err = srp_direct_data(cmd, md, dir, rdma_io, dma_map, ext_desc);
 324                 break;
 325         case SRP_DATA_DESC_INDIRECT:
 326                 id = (struct srp_indirect_buf *)(srp_cmd->add_data + offset);
 327                 err = srp_indirect_data(cmd, srp_cmd, id, dir, rdma_io, dma_map,
 328                                         ext_desc);
 329                 break;
 330         default:
 331                 pr_err("Unknown format %d %x\n", dir, format);
 332                 err = -EINVAL;
 333         }
 334
 335         return err;
 336 }
 337
 338 u64 srp_data_length(struct srp_cmd *cmd, enum dma_data_direction dir)
 339 {
 340         struct srp_direct_buf *md;
 341         struct srp_indirect_buf *id;
 342         u64 len = 0;
 343         uint offset = cmd->add_cdb_len & ~3;
 344         u8 fmt;
 345
 346         if (dir == DMA_TO_DEVICE) {
 347                 fmt = cmd->buf_fmt >> 4;
 348         } else {
 349                 fmt = cmd->buf_fmt & ((1U << 4) - 1);
 350                 offset += data_out_desc_size(cmd);
 351         }
 352
 353         switch (fmt) {
 354         case SRP_NO_DATA_DESC:
 355                 break;
 356         case SRP_DATA_DESC_DIRECT:
 357                 md = (struct srp_direct_buf *)(cmd->add_data + offset);
 358                 len = be32_to_cpu(md->len);
 359                 break;
 360         case SRP_DATA_DESC_INDIRECT:
 361                 id = (struct srp_indirect_buf *)(cmd->add_data + offset);
 362                 len = be32_to_cpu(id->len);
 363                 break;
 364         default:
 365                 pr_err("invalid data format %x\n", fmt);
 366                 break;
 367         }
 368         return len;
 369 }
 370
 371 int srp_get_desc_table(struct srp_cmd *srp_cmd, enum dma_data_direction *dir,
 372                        u64 *data_len)
 373 {
 374         struct srp_indirect_buf *idb;
 375         struct srp_direct_buf *db;
 376         uint add_cdb_offset;
 377         int rc;
 378
 379         /*
 380          * The pointer computations below will only be compiled correctly
 381          * if srp_cmd::add_data is declared as s8*, u8*, s8[] or u8[], so check
 382          * whether srp_cmd::add_data has been declared as a byte pointer.
 383          */
 384         BUILD_BUG_ON(!__same_type(srp_cmd->add_data[0], (s8)0)
 385                      && !__same_type(srp_cmd->add_data[0], (u8)0));
 386
 387         BUG_ON(!dir);
 388         BUG_ON(!data_len);
 389
 390         rc = 0;
 391         *data_len = 0;
 392
 393         *dir = DMA_NONE;
 394
 395         if (srp_cmd->buf_fmt & 0xf)
 396                 *dir = DMA_FROM_DEVICE;
 397         else if (srp_cmd->buf_fmt >> 4)
 398                 *dir = DMA_TO_DEVICE;
 399
 400         add_cdb_offset = srp_cmd->add_cdb_len & ~3;
 401         if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_DIRECT) ||
 402             ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_DIRECT)) {
 403                 db = (struct srp_direct_buf *)(srp_cmd->add_data
 404                                                + add_cdb_offset);
 405                 *data_len = be32_to_cpu(db->len);
 406         } else if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_INDIRECT) ||
 407                    ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_INDIRECT)) {
 408                 idb = (struct srp_indirect_buf *)(srp_cmd->add_data
 409                                                   + add_cdb_offset);
 410
 411                 *data_len = be32_to_cpu(idb->len);
 412         }
 413         return rc;
 414 }
 415
 416 MODULE_DESCRIPTION("SCSI RDMA Protocol lib functions");
 417 MODULE_AUTHOR("FUJITA Tomonori");
 418 MODULE_LICENSE("GPL");