drivers/infiniband/ulp/iser/iser_memory.c

   1 /*
   2  * Copyright (c) 2004, 2005, 2006 Voltaire, Inc. All rights reserved.
   3  *
   4  * This software is available to you under a choice of one of two
   5  * licenses.  You may choose to be licensed under the terms of the GNU
   6  * General Public License (GPL) Version 2, available from the file
   7  * COPYING in the main directory of this source tree, or the
   8  * OpenIB.org BSD license below:
   9  *
  10  *     Redistribution and use in source and binary forms, with or
  11  *     without modification, are permitted provided that the following
  12  *     conditions are met:
  13  *
  14  *      - Redistributions of source code must retain the above
  15  *        copyright notice, this list of conditions and the following
  16  *        disclaimer.
  17  *
  18  *      - Redistributions in binary form must reproduce the above
  19  *        copyright notice, this list of conditions and the following
  20  *        disclaimer in the documentation and/or other materials
  21  *        provided with the distribution.
  22  *
  23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  30  * SOFTWARE.
  31  *
  32  * $Id: iser_memory.c 6964 2006-05-07 11:11:43Z ogerlitz $
  33  */
  34 #include <linux/module.h>
  35 #include <linux/kernel.h>
  36 #include <linux/slab.h>
  37 #include <linux/mm.h>
  38 #include <linux/highmem.h>
  39 #include <asm/io.h>
  40 #include <asm/scatterlist.h>
  41 #include <linux/scatterlist.h>
  42
  43 #include "iscsi_iser.h"
  44
  45 #define ISER_KMALLOC_THRESHOLD 0x20000 /* 128K - kmalloc limit */
  46
  47 /**
  48  * Decrements the reference count for the
  49  * registered buffer & releases it
  50  *
  51  * returns 0 if released, 1 if deferred
  52  */
  53 int iser_regd_buff_release(struct iser_regd_buf *regd_buf)
  54 {
  55         struct ib_device *dev;
  56
  57         if ((atomic_read(&regd_buf->ref_count) == 0) ||
  58             atomic_dec_and_test(&regd_buf->ref_count)) {
  59                 /* if we used the dma mr, unreg is just NOP */
  60                 if (regd_buf->reg.is_fmr)
  61                         iser_unreg_mem(&regd_buf->reg);
  62
  63                 if (regd_buf->dma_addr) {
  64                         dev = regd_buf->device->ib_device;
  65                         ib_dma_unmap_single(dev,
  66                                          regd_buf->dma_addr,
  67                                          regd_buf->data_size,
  68                                          regd_buf->direction);
  69                 }
  70                 /* else this regd buf is associated with task which we */
  71                 /* dma_unmap_single/sg later */
  72                 return 0;
  73         } else {
  74                 iser_dbg("Release deferred, regd.buff: 0x%p\n", regd_buf);
  75                 return 1;
  76         }
  77 }
  78
  79 /**
  80  * iser_reg_single - fills registered buffer descriptor with
  81  *                   registration information
  82  */
  83 void iser_reg_single(struct iser_device *device,
  84                      struct iser_regd_buf *regd_buf,
  85                      enum dma_data_direction direction)
  86 {
  87         u64 dma_addr;
  88
  89         dma_addr = ib_dma_map_single(device->ib_device,
  90                                      regd_buf->virt_addr,
  91                                      regd_buf->data_size, direction);
  92         BUG_ON(ib_dma_mapping_error(device->ib_device, dma_addr));
  93
  94         regd_buf->reg.lkey = device->mr->lkey;
  95         regd_buf->reg.len  = regd_buf->data_size;
  96         regd_buf->reg.va   = dma_addr;
  97         regd_buf->reg.is_fmr = 0;
  98
  99         regd_buf->dma_addr  = dma_addr;
 100         regd_buf->direction = direction;
 101 }
 102
 103 /**
 104  * iser_start_rdma_unaligned_sg
 105  */
 106 int iser_start_rdma_unaligned_sg(struct iscsi_iser_cmd_task  *iser_ctask,
 107                                  enum iser_data_dir cmd_dir)
 108 {
 109         int dma_nents;
 110         struct ib_device *dev;
 111         char *mem = NULL;
 112         struct iser_data_buf *data = &iser_ctask->data[cmd_dir];
 113         unsigned long  cmd_data_len = data->data_len;
 114
 115         if (cmd_data_len > ISER_KMALLOC_THRESHOLD)
 116                 mem = (void *)__get_free_pages(GFP_NOIO,
 117                       ilog2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT);
 118         else
 119                 mem = kmalloc(cmd_data_len, GFP_NOIO);
 120
 121         if (mem == NULL) {
 122                 iser_err("Failed to allocate mem size %d %d for copying sglist\n",
 123                          data->size,(int)cmd_data_len);
 124                 return -ENOMEM;
 125         }
 126
 127         if (cmd_dir == ISER_DIR_OUT) {
 128                 /* copy the unaligned sg the buffer which is used for RDMA */
 129                 struct scatterlist *sg = (struct scatterlist *)data->buf;
 130                 int i;
 131                 char *p, *from;
 132
 133                 for (p = mem, i = 0; i < data->size; i++) {
 134                         from = kmap_atomic(sg[i].page, KM_USER0);
 135                         memcpy(p,
 136                                from + sg[i].offset,
 137                                sg[i].length);
 138                         kunmap_atomic(from, KM_USER0);
 139                         p += sg[i].length;
 140                 }
 141         }
 142
 143         sg_init_one(&iser_ctask->data_copy[cmd_dir].sg_single, mem, cmd_data_len);
 144         iser_ctask->data_copy[cmd_dir].buf  =
 145                 &iser_ctask->data_copy[cmd_dir].sg_single;
 146         iser_ctask->data_copy[cmd_dir].size = 1;
 147
 148         iser_ctask->data_copy[cmd_dir].copy_buf  = mem;
 149
 150         dev = iser_ctask->iser_conn->ib_conn->device->ib_device;
 151         dma_nents = ib_dma_map_sg(dev,
 152                                   &iser_ctask->data_copy[cmd_dir].sg_single,
 153                                   1,
 154                                   (cmd_dir == ISER_DIR_OUT) ?
 155                                   DMA_TO_DEVICE : DMA_FROM_DEVICE);
 156         BUG_ON(dma_nents == 0);
 157
 158         iser_ctask->data_copy[cmd_dir].dma_nents = dma_nents;
 159         return 0;
 160 }
 161
 162 /**
 163  * iser_finalize_rdma_unaligned_sg
 164  */
 165 void iser_finalize_rdma_unaligned_sg(struct iscsi_iser_cmd_task *iser_ctask,
 166                                      enum iser_data_dir         cmd_dir)
 167 {
 168         struct ib_device *dev;
 169         struct iser_data_buf *mem_copy;
 170         unsigned long  cmd_data_len;
 171
 172         dev = iser_ctask->iser_conn->ib_conn->device->ib_device;
 173         mem_copy = &iser_ctask->data_copy[cmd_dir];
 174
 175         ib_dma_unmap_sg(dev, &mem_copy->sg_single, 1,
 176                         (cmd_dir == ISER_DIR_OUT) ?
 177                         DMA_TO_DEVICE : DMA_FROM_DEVICE);
 178
 179         if (cmd_dir == ISER_DIR_IN) {
 180                 char *mem;
 181                 struct scatterlist *sg;
 182                 unsigned char *p, *to;
 183                 unsigned int sg_size;
 184                 int i;
 185
 186                 /* copy back read RDMA to unaligned sg */
 187                 mem     = mem_copy->copy_buf;
 188
 189                 sg      = (struct scatterlist *)iser_ctask->data[ISER_DIR_IN].buf;
 190                 sg_size = iser_ctask->data[ISER_DIR_IN].size;
 191
 192                 for (p = mem, i = 0; i < sg_size; i++){
 193                         to = kmap_atomic(sg[i].page, KM_SOFTIRQ0);
 194                         memcpy(to + sg[i].offset,
 195                                p,
 196                                sg[i].length);
 197                         kunmap_atomic(to, KM_SOFTIRQ0);
 198                         p += sg[i].length;
 199                 }
 200         }
 201
 202         cmd_data_len = iser_ctask->data[cmd_dir].data_len;
 203
 204         if (cmd_data_len > ISER_KMALLOC_THRESHOLD)
 205                 free_pages((unsigned long)mem_copy->copy_buf,
 206                            ilog2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT);
 207         else
 208                 kfree(mem_copy->copy_buf);
 209
 210         mem_copy->copy_buf = NULL;
 211 }
 212
 213 /**
 214  * iser_sg_to_page_vec - Translates scatterlist entries to physical addresses
 215  * and returns the length of resulting physical address array (may be less than
 216  * the original due to possible compaction).
 217  *
 218  * we build a "page vec" under the assumption that the SG meets the RDMA
 219  * alignment requirements. Other then the first and last SG elements, all
 220  * the "internal" elements can be compacted into a list whose elements are
 221  * dma addresses of physical pages. The code supports also the weird case
 222  * where --few fragments of the same page-- are present in the SG as
 223  * consecutive elements. Also, it handles one entry SG.
 224  */
 225 static int iser_sg_to_page_vec(struct iser_data_buf *data,
 226                                struct iser_page_vec *page_vec,
 227                                struct ib_device *ibdev)
 228 {
 229         struct scatterlist *sg = (struct scatterlist *)data->buf;
 230         u64 first_addr, last_addr, page;
 231         int end_aligned;
 232         unsigned int cur_page = 0;
 233         unsigned long total_sz = 0;
 234         int i;
 235
 236         /* compute the offset of first element */
 237         page_vec->offset = (u64) sg[0].offset & ~MASK_4K;
 238
 239         for (i = 0; i < data->dma_nents; i++) {
 240                 unsigned int dma_len = ib_sg_dma_len(ibdev, &sg[i]);
 241
 242                 total_sz += dma_len;
 243
 244                 first_addr = ib_sg_dma_address(ibdev, &sg[i]);
 245                 last_addr  = first_addr + dma_len;
 246
 247                 end_aligned   = !(last_addr  & ~MASK_4K);
 248
 249                 /* continue to collect page fragments till aligned or SG ends */
 250                 while (!end_aligned && (i + 1 < data->dma_nents)) {
 251                         i++;
 252                         dma_len = ib_sg_dma_len(ibdev, &sg[i]);
 253                         total_sz += dma_len;
 254                         last_addr = ib_sg_dma_address(ibdev, &sg[i]) + dma_len;
 255                         end_aligned = !(last_addr  & ~MASK_4K);
 256                 }
 257
 258                 /* handle the 1st page in the 1st DMA element */
 259                 if (cur_page == 0) {
 260                         page = first_addr & MASK_4K;
 261                         page_vec->pages[cur_page] = page;
 262                         cur_page++;
 263                         page += SIZE_4K;
 264                 } else
 265                         page = first_addr;
 266
 267                 for (; page < last_addr; page += SIZE_4K) {
 268                         page_vec->pages[cur_page] = page;
 269                         cur_page++;
 270                 }
 271
 272         }
 273         page_vec->data_size = total_sz;
 274         iser_dbg("page_vec->data_size:%d cur_page %d\n", page_vec->data_size,cur_page);
 275         return cur_page;
 276 }
 277
 278 #define IS_4K_ALIGNED(addr)     ((((unsigned long)addr) & ~MASK_4K) == 0)
 279
 280 /**
 281  * iser_data_buf_aligned_len - Tries to determine the maximal correctly aligned
 282  * for RDMA sub-list of a scatter-gather list of memory buffers, and  returns
 283  * the number of entries which are aligned correctly. Supports the case where
 284  * consecutive SG elements are actually fragments of the same physcial page.
 285  */
 286 static unsigned int iser_data_buf_aligned_len(struct iser_data_buf *data,
 287                                               struct ib_device *ibdev)
 288 {
 289         struct scatterlist *sg;
 290         u64 end_addr, next_addr;
 291         int i, cnt;
 292         unsigned int ret_len = 0;
 293
 294         sg = (struct scatterlist *)data->buf;
 295
 296         for (cnt = 0, i = 0; i < data->dma_nents; i++, cnt++) {
 297                 /* iser_dbg("Checking sg iobuf [%d]: phys=0x%08lX "
 298                    "offset: %ld sz: %ld\n", i,
 299                    (unsigned long)page_to_phys(sg[i].page),
 300                    (unsigned long)sg[i].offset,
 301                    (unsigned long)sg[i].length); */
 302                 end_addr = ib_sg_dma_address(ibdev, &sg[i]) +
 303                            ib_sg_dma_len(ibdev, &sg[i]);
 304                 /* iser_dbg("Checking sg iobuf end address "
 305                        "0x%08lX\n", end_addr); */
 306                 if (i + 1 < data->dma_nents) {
 307                         next_addr = ib_sg_dma_address(ibdev, &sg[i+1]);
 308                         /* are i, i+1 fragments of the same page? */
 309                         if (end_addr == next_addr)
 310                                 continue;
 311                         else if (!IS_4K_ALIGNED(end_addr)) {
 312                                 ret_len = cnt + 1;
 313                                 break;
 314                         }
 315                 }
 316         }
 317         if (i == data->dma_nents)
 318                 ret_len = cnt;  /* loop ended */
 319         iser_dbg("Found %d aligned entries out of %d in sg:0x%p\n",
 320                  ret_len, data->dma_nents, data);
 321         return ret_len;
 322 }
 323
 324 static void iser_data_buf_dump(struct iser_data_buf *data,
 325                                struct ib_device *ibdev)
 326 {
 327         struct scatterlist *sg = (struct scatterlist *)data->buf;
 328         int i;
 329
 330         for (i = 0; i < data->dma_nents; i++)
 331                 iser_err("sg[%d] dma_addr:0x%lX page:0x%p "
 332                          "off:0x%x sz:0x%x dma_len:0x%x\n",
 333                          i, (unsigned long)ib_sg_dma_address(ibdev, &sg[i]),
 334                          sg[i].page, sg[i].offset,
 335                          sg[i].length, ib_sg_dma_len(ibdev, &sg[i]));
 336 }
 337
 338 static void iser_dump_page_vec(struct iser_page_vec *page_vec)
 339 {
 340         int i;
 341
 342         iser_err("page vec length %d data size %d\n",
 343                  page_vec->length, page_vec->data_size);
 344         for (i = 0; i < page_vec->length; i++)
 345                 iser_err("%d %lx\n",i,(unsigned long)page_vec->pages[i]);
 346 }
 347
 348 static void iser_page_vec_build(struct iser_data_buf *data,
 349                                 struct iser_page_vec *page_vec,
 350                                 struct ib_device *ibdev)
 351 {
 352         int page_vec_len = 0;
 353
 354         page_vec->length = 0;
 355         page_vec->offset = 0;
 356
 357         iser_dbg("Translating sg sz: %d\n", data->dma_nents);
 358         page_vec_len = iser_sg_to_page_vec(data, page_vec, ibdev);
 359         iser_dbg("sg len %d page_vec_len %d\n", data->dma_nents,page_vec_len);
 360
 361         page_vec->length = page_vec_len;
 362
 363         if (page_vec_len * SIZE_4K < page_vec->data_size) {
 364                 iser_err("page_vec too short to hold this SG\n");
 365                 iser_data_buf_dump(data, ibdev);
 366                 iser_dump_page_vec(page_vec);
 367                 BUG();
 368         }
 369 }
 370
 371 int iser_dma_map_task_data(struct iscsi_iser_cmd_task *iser_ctask,
 372                             struct iser_data_buf       *data,
 373                             enum   iser_data_dir       iser_dir,
 374                             enum   dma_data_direction  dma_dir)
 375 {
 376         struct ib_device *dev;
 377
 378         iser_ctask->dir[iser_dir] = 1;
 379         dev = iser_ctask->iser_conn->ib_conn->device->ib_device;
 380
 381         data->dma_nents = ib_dma_map_sg(dev, data->buf, data->size, dma_dir);
 382         if (data->dma_nents == 0) {
 383                 iser_err("dma_map_sg failed!!!\n");
 384                 return -EINVAL;
 385         }
 386         return 0;
 387 }
 388
 389 void iser_dma_unmap_task_data(struct iscsi_iser_cmd_task *iser_ctask)
 390 {
 391         struct ib_device *dev;
 392         struct iser_data_buf *data;
 393
 394         dev = iser_ctask->iser_conn->ib_conn->device->ib_device;
 395
 396         if (iser_ctask->dir[ISER_DIR_IN]) {
 397                 data = &iser_ctask->data[ISER_DIR_IN];
 398                 ib_dma_unmap_sg(dev, data->buf, data->size, DMA_FROM_DEVICE);
 399         }
 400
 401         if (iser_ctask->dir[ISER_DIR_OUT]) {
 402                 data = &iser_ctask->data[ISER_DIR_OUT];
 403                 ib_dma_unmap_sg(dev, data->buf, data->size, DMA_TO_DEVICE);
 404         }
 405 }
 406
 407 /**
 408  * iser_reg_rdma_mem - Registers memory intended for RDMA,
 409  * obtaining rkey and va
 410  *
 411  * returns 0 on success, errno code on failure
 412  */
 413 int iser_reg_rdma_mem(struct iscsi_iser_cmd_task *iser_ctask,
 414                       enum   iser_data_dir        cmd_dir)
 415 {
 416         struct iser_conn     *ib_conn = iser_ctask->iser_conn->ib_conn;
 417         struct iser_device   *device = ib_conn->device;
 418         struct ib_device     *ibdev = device->ib_device;
 419         struct iser_data_buf *mem = &iser_ctask->data[cmd_dir];
 420         struct iser_regd_buf *regd_buf;
 421         int aligned_len;
 422         int err;
 423         int i;
 424         struct scatterlist *sg;
 425
 426         regd_buf = &iser_ctask->rdma_regd[cmd_dir];
 427
 428         aligned_len = iser_data_buf_aligned_len(mem, ibdev);
 429         if (aligned_len != mem->dma_nents) {
 430                 iser_err("rdma alignment violation %d/%d aligned\n",
 431                          aligned_len, mem->size);
 432                 iser_data_buf_dump(mem, ibdev);
 433
 434                 /* unmap the command data before accessing it */
 435                 iser_dma_unmap_task_data(iser_ctask);
 436
 437                 /* allocate copy buf, if we are writing, copy the */
 438                 /* unaligned scatterlist, dma map the copy        */
 439                 if (iser_start_rdma_unaligned_sg(iser_ctask, cmd_dir) != 0)
 440                                 return -ENOMEM;
 441                 mem = &iser_ctask->data_copy[cmd_dir];
 442         }
 443
 444         /* if there a single dma entry, FMR is not needed */
 445         if (mem->dma_nents == 1) {
 446                 sg = (struct scatterlist *)mem->buf;
 447
 448                 regd_buf->reg.lkey = device->mr->lkey;
 449                 regd_buf->reg.rkey = device->mr->rkey;
 450                 regd_buf->reg.len  = ib_sg_dma_len(ibdev, &sg[0]);
 451                 regd_buf->reg.va   = ib_sg_dma_address(ibdev, &sg[0]);
 452                 regd_buf->reg.is_fmr = 0;
 453
 454                 iser_dbg("PHYSICAL Mem.register: lkey: 0x%08X rkey: 0x%08X  "
 455                          "va: 0x%08lX sz: %ld]\n",
 456                          (unsigned int)regd_buf->reg.lkey,
 457                          (unsigned int)regd_buf->reg.rkey,
 458                          (unsigned long)regd_buf->reg.va,
 459                          (unsigned long)regd_buf->reg.len);
 460         } else { /* use FMR for multiple dma entries */
 461                 iser_page_vec_build(mem, ib_conn->page_vec, ibdev);
 462                 err = iser_reg_page_vec(ib_conn, ib_conn->page_vec, &regd_buf->reg);
 463                 if (err) {
 464                         iser_data_buf_dump(mem, ibdev);
 465                         iser_err("mem->dma_nents = %d (dlength = 0x%x)\n", mem->dma_nents,
 466                                  ntoh24(iser_ctask->desc.iscsi_header.dlength));
 467                         iser_err("page_vec: data_size = 0x%x, length = %d, offset = 0x%x\n",
 468                                  ib_conn->page_vec->data_size, ib_conn->page_vec->length,
 469                                  ib_conn->page_vec->offset);
 470                         for (i=0 ; i<ib_conn->page_vec->length ; i++)
 471                                 iser_err("page_vec[%d] = 0x%llx\n", i,
 472                                          (unsigned long long) ib_conn->page_vec->pages[i]);
 473                         return err;
 474                 }
 475         }
 476
 477         /* take a reference on this regd buf such that it will not be released *
 478          * (eg in send dto completion) before we get the scsi response         */
 479         atomic_inc(&regd_buf->ref_count);
 480         return 0;
 481 }