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