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   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 *sgl = (struct scatterlist *)data->buf;
 128                 struct scatterlist *sg;
 129                 int i;
 130                 char *p, *from;
 131
 132                 p = mem;
 133                 for_each_sg(sgl, sg, data->size, i) {
 134                         from = kmap_atomic(sg_page(sg), KM_USER0);
 135                         memcpy(p,
 136                                from + sg->offset,
 137                                sg->length);
 138                         kunmap_atomic(from, KM_USER0);
 139                         p += sg->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 *sgl, *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                 sgl     = (struct scatterlist *)iser_ctask->data[ISER_DIR_IN].buf;
 190                 sg_size = iser_ctask->data[ISER_DIR_IN].size;
 191
 192                 p = mem;
 193                 for_each_sg(sgl, sg, sg_size, i) {
 194                         to = kmap_atomic(sg_page(sg), KM_SOFTIRQ0);
 195                         memcpy(to + sg->offset,
 196                                p,
 197                                sg->length);
 198                         kunmap_atomic(to, KM_SOFTIRQ0);
 199                         p += sg->length;
 200                 }
 201         }
 202
 203         cmd_data_len = iser_ctask->data[cmd_dir].data_len;
 204
 205         if (cmd_data_len > ISER_KMALLOC_THRESHOLD)
 206                 free_pages((unsigned long)mem_copy->copy_buf,
 207                            ilog2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT);
 208         else
 209                 kfree(mem_copy->copy_buf);
 210
 211         mem_copy->copy_buf = NULL;
 212 }
 213
 214 /**
 215  * iser_sg_to_page_vec - Translates scatterlist entries to physical addresses
 216  * and returns the length of resulting physical address array (may be less than
 217  * the original due to possible compaction).
 218  *
 219  * we build a "page vec" under the assumption that the SG meets the RDMA
 220  * alignment requirements. Other then the first and last SG elements, all
 221  * the "internal" elements can be compacted into a list whose elements are
 222  * dma addresses of physical pages. The code supports also the weird case
 223  * where --few fragments of the same page-- are present in the SG as
 224  * consecutive elements. Also, it handles one entry SG.
 225  */
 226 static int iser_sg_to_page_vec(struct iser_data_buf *data,
 227                                struct iser_page_vec *page_vec,
 228                                struct ib_device *ibdev)
 229 {
 230         struct scatterlist *sgl = (struct scatterlist *)data->buf;
 231         struct scatterlist *sg;
 232         u64 first_addr, last_addr, page;
 233         int end_aligned;
 234         unsigned int cur_page = 0;
 235         unsigned long total_sz = 0;
 236         int i;
 237
 238         /* compute the offset of first element */
 239         page_vec->offset = (u64) sgl[0].offset & ~MASK_4K;
 240
 241         for_each_sg(sgl, sg, data->dma_nents, i) {
 242                 unsigned int dma_len = ib_sg_dma_len(ibdev, sg);
 243
 244                 total_sz += dma_len;
 245
 246                 first_addr = ib_sg_dma_address(ibdev, sg);
 247                 last_addr  = first_addr + dma_len;
 248
 249                 end_aligned   = !(last_addr  & ~MASK_4K);
 250
 251                 /* continue to collect page fragments till aligned or SG ends */
 252                 while (!end_aligned && (i + 1 < data->dma_nents)) {
 253                         sg = sg_next(sg);
 254                         i++;
 255                         dma_len = ib_sg_dma_len(ibdev, sg);
 256                         total_sz += dma_len;
 257                         last_addr = ib_sg_dma_address(ibdev, sg) + dma_len;
 258                         end_aligned = !(last_addr  & ~MASK_4K);
 259                 }
 260
 261                 /* handle the 1st page in the 1st DMA element */
 262                 if (cur_page == 0) {
 263                         page = first_addr & MASK_4K;
 264                         page_vec->pages[cur_page] = page;
 265                         cur_page++;
 266                         page += SIZE_4K;
 267                 } else
 268                         page = first_addr;
 269
 270                 for (; page < last_addr; page += SIZE_4K) {
 271                         page_vec->pages[cur_page] = page;
 272                         cur_page++;
 273                 }
 274
 275         }
 276         page_vec->data_size = total_sz;
 277         iser_dbg("page_vec->data_size:%d cur_page %d\n", page_vec->data_size,cur_page);
 278         return cur_page;
 279 }
 280
 281 #define IS_4K_ALIGNED(addr)     ((((unsigned long)addr) & ~MASK_4K) == 0)
 282
 283 /**
 284  * iser_data_buf_aligned_len - Tries to determine the maximal correctly aligned
 285  * for RDMA sub-list of a scatter-gather list of memory buffers, and  returns
 286  * the number of entries which are aligned correctly. Supports the case where
 287  * consecutive SG elements are actually fragments of the same physcial page.
 288  */
 289 static unsigned int iser_data_buf_aligned_len(struct iser_data_buf *data,
 290                                               struct ib_device *ibdev)
 291 {
 292         struct scatterlist *sgl, *sg;
 293         u64 end_addr, next_addr;
 294         int i, cnt;
 295         unsigned int ret_len = 0;
 296
 297         sgl = (struct scatterlist *)data->buf;
 298
 299         cnt = 0;
 300         for_each_sg(sgl, sg, data->dma_nents, i) {
 301                 /* iser_dbg("Checking sg iobuf [%d]: phys=0x%08lX "
 302                    "offset: %ld sz: %ld\n", i,
 303                    (unsigned long)sg_phys(sg),
 304                    (unsigned long)sg->offset,
 305                    (unsigned long)sg->length); */
 306                 end_addr = ib_sg_dma_address(ibdev, sg) +
 307                            ib_sg_dma_len(ibdev, sg);
 308                 /* iser_dbg("Checking sg iobuf end address "
 309                        "0x%08lX\n", end_addr); */
 310                 if (i + 1 < data->dma_nents) {
 311                         next_addr = ib_sg_dma_address(ibdev, sg_next(sg));
 312                         /* are i, i+1 fragments of the same page? */
 313                         if (end_addr == next_addr) {
 314                                 cnt++;
 315                                 continue;
 316                         } else if (!IS_4K_ALIGNED(end_addr)) {
 317                                 ret_len = cnt + 1;
 318                                 break;
 319                         }
 320                 }
 321                 cnt++;
 322         }
 323         if (i == data->dma_nents)
 324                 ret_len = cnt;  /* loop ended */
 325         iser_dbg("Found %d aligned entries out of %d in sg:0x%p\n",
 326                  ret_len, data->dma_nents, data);
 327         return ret_len;
 328 }
 329
 330 static void iser_data_buf_dump(struct iser_data_buf *data,
 331                                struct ib_device *ibdev)
 332 {
 333         struct scatterlist *sgl = (struct scatterlist *)data->buf;
 334         struct scatterlist *sg;
 335         int i;
 336
 337         for_each_sg(sgl, sg, data->dma_nents, i)
 338                 iser_err("sg[%d] dma_addr:0x%lX page:0x%p "
 339                          "off:0x%x sz:0x%x dma_len:0x%x\n",
 340                          i, (unsigned long)ib_sg_dma_address(ibdev, sg),
 341                          sg_page(sg), sg->offset,
 342                          sg->length, ib_sg_dma_len(ibdev, sg));
 343 }
 344
 345 static void iser_dump_page_vec(struct iser_page_vec *page_vec)
 346 {
 347         int i;
 348
 349         iser_err("page vec length %d data size %d\n",
 350                  page_vec->length, page_vec->data_size);
 351         for (i = 0; i < page_vec->length; i++)
 352                 iser_err("%d %lx\n",i,(unsigned long)page_vec->pages[i]);
 353 }
 354
 355 static void iser_page_vec_build(struct iser_data_buf *data,
 356                                 struct iser_page_vec *page_vec,
 357                                 struct ib_device *ibdev)
 358 {
 359         int page_vec_len = 0;
 360
 361         page_vec->length = 0;
 362         page_vec->offset = 0;
 363
 364         iser_dbg("Translating sg sz: %d\n", data->dma_nents);
 365         page_vec_len = iser_sg_to_page_vec(data, page_vec, ibdev);
 366         iser_dbg("sg len %d page_vec_len %d\n", data->dma_nents,page_vec_len);
 367
 368         page_vec->length = page_vec_len;
 369
 370         if (page_vec_len * SIZE_4K < page_vec->data_size) {
 371                 iser_err("page_vec too short to hold this SG\n");
 372                 iser_data_buf_dump(data, ibdev);
 373                 iser_dump_page_vec(page_vec);
 374                 BUG();
 375         }
 376 }
 377
 378 int iser_dma_map_task_data(struct iscsi_iser_cmd_task *iser_ctask,
 379                             struct iser_data_buf       *data,
 380                             enum   iser_data_dir       iser_dir,
 381                             enum   dma_data_direction  dma_dir)
 382 {
 383         struct ib_device *dev;
 384
 385         iser_ctask->dir[iser_dir] = 1;
 386         dev = iser_ctask->iser_conn->ib_conn->device->ib_device;
 387
 388         data->dma_nents = ib_dma_map_sg(dev, data->buf, data->size, dma_dir);
 389         if (data->dma_nents == 0) {
 390                 iser_err("dma_map_sg failed!!!\n");
 391                 return -EINVAL;
 392         }
 393         return 0;
 394 }
 395
 396 void iser_dma_unmap_task_data(struct iscsi_iser_cmd_task *iser_ctask)
 397 {
 398         struct ib_device *dev;
 399         struct iser_data_buf *data;
 400
 401         dev = iser_ctask->iser_conn->ib_conn->device->ib_device;
 402
 403         if (iser_ctask->dir[ISER_DIR_IN]) {
 404                 data = &iser_ctask->data[ISER_DIR_IN];
 405                 ib_dma_unmap_sg(dev, data->buf, data->size, DMA_FROM_DEVICE);
 406         }
 407
 408         if (iser_ctask->dir[ISER_DIR_OUT]) {
 409                 data = &iser_ctask->data[ISER_DIR_OUT];
 410                 ib_dma_unmap_sg(dev, data->buf, data->size, DMA_TO_DEVICE);
 411         }
 412 }
 413
 414 /**
 415  * iser_reg_rdma_mem - Registers memory intended for RDMA,
 416  * obtaining rkey and va
 417  *
 418  * returns 0 on success, errno code on failure
 419  */
 420 int iser_reg_rdma_mem(struct iscsi_iser_cmd_task *iser_ctask,
 421                       enum   iser_data_dir        cmd_dir)
 422 {
 423         struct iser_conn     *ib_conn = iser_ctask->iser_conn->ib_conn;
 424         struct iser_device   *device = ib_conn->device;
 425         struct ib_device     *ibdev = device->ib_device;
 426         struct iser_data_buf *mem = &iser_ctask->data[cmd_dir];
 427         struct iser_regd_buf *regd_buf;
 428         int aligned_len;
 429         int err;
 430         int i;
 431         struct scatterlist *sg;
 432
 433         regd_buf = &iser_ctask->rdma_regd[cmd_dir];
 434
 435         aligned_len = iser_data_buf_aligned_len(mem, ibdev);
 436         if (aligned_len != mem->dma_nents) {
 437                 iser_err("rdma alignment violation %d/%d aligned\n",
 438                          aligned_len, mem->size);
 439                 iser_data_buf_dump(mem, ibdev);
 440
 441                 /* unmap the command data before accessing it */
 442                 iser_dma_unmap_task_data(iser_ctask);
 443
 444                 /* allocate copy buf, if we are writing, copy the */
 445                 /* unaligned scatterlist, dma map the copy        */
 446                 if (iser_start_rdma_unaligned_sg(iser_ctask, cmd_dir) != 0)
 447                                 return -ENOMEM;
 448                 mem = &iser_ctask->data_copy[cmd_dir];
 449         }
 450
 451         /* if there a single dma entry, FMR is not needed */
 452         if (mem->dma_nents == 1) {
 453                 sg = (struct scatterlist *)mem->buf;
 454
 455                 regd_buf->reg.lkey = device->mr->lkey;
 456                 regd_buf->reg.rkey = device->mr->rkey;
 457                 regd_buf->reg.len  = ib_sg_dma_len(ibdev, &sg[0]);
 458                 regd_buf->reg.va   = ib_sg_dma_address(ibdev, &sg[0]);
 459                 regd_buf->reg.is_fmr = 0;
 460
 461                 iser_dbg("PHYSICAL Mem.register: lkey: 0x%08X rkey: 0x%08X  "
 462                          "va: 0x%08lX sz: %ld]\n",
 463                          (unsigned int)regd_buf->reg.lkey,
 464                          (unsigned int)regd_buf->reg.rkey,
 465                          (unsigned long)regd_buf->reg.va,
 466                          (unsigned long)regd_buf->reg.len);
 467         } else { /* use FMR for multiple dma entries */
 468                 iser_page_vec_build(mem, ib_conn->page_vec, ibdev);
 469                 err = iser_reg_page_vec(ib_conn, ib_conn->page_vec, &regd_buf->reg);
 470                 if (err) {
 471                         iser_data_buf_dump(mem, ibdev);
 472                         iser_err("mem->dma_nents = %d (dlength = 0x%x)\n", mem->dma_nents,
 473                                  ntoh24(iser_ctask->desc.iscsi_header.dlength));
 474                         iser_err("page_vec: data_size = 0x%x, length = %d, offset = 0x%x\n",
 475                                  ib_conn->page_vec->data_size, ib_conn->page_vec->length,
 476                                  ib_conn->page_vec->offset);
 477                         for (i=0 ; i<ib_conn->page_vec->length ; i++)
 478                                 iser_err("page_vec[%d] = 0x%llx\n", i,
 479                                          (unsigned long long) ib_conn->page_vec->pages[i]);
 480                         return err;
 481                 }
 482         }
 483
 484         /* take a reference on this regd buf such that it will not be released *
 485          * (eg in send dto completion) before we get the scsi response         */
 486         atomic_inc(&regd_buf->ref_count);
 487         return 0;
 488 }