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 #include <linux/module.h>
  33 #include <linux/kernel.h>
  34 #include <linux/slab.h>
  35 #include <linux/mm.h>
  36 #include <linux/highmem.h>
  37 #include <linux/scatterlist.h>
  38
  39 #include "iscsi_iser.h"
  40
  41 #define ISER_KMALLOC_THRESHOLD 0x20000 /* 128K - kmalloc limit */
  42
  43 /**
  44  * Decrements the reference count for the
  45  * registered buffer & releases it
  46  *
  47  * returns 0 if released, 1 if deferred
  48  */
  49 int iser_regd_buff_release(struct iser_regd_buf *regd_buf)
  50 {
  51         struct ib_device *dev;
  52
  53         if ((atomic_read(&regd_buf->ref_count) == 0) ||
  54             atomic_dec_and_test(&regd_buf->ref_count)) {
  55                 /* if we used the dma mr, unreg is just NOP */
  56                 if (regd_buf->reg.is_fmr)
  57                         iser_unreg_mem(&regd_buf->reg);
  58
  59                 if (regd_buf->dma_addr) {
  60                         dev = regd_buf->device->ib_device;
  61                         ib_dma_unmap_single(dev,
  62                                          regd_buf->dma_addr,
  63                                          regd_buf->data_size,
  64                                          regd_buf->direction);
  65                 }
  66                 /* else this regd buf is associated with task which we */
  67                 /* dma_unmap_single/sg later */
  68                 return 0;
  69         } else {
  70                 iser_dbg("Release deferred, regd.buff: 0x%p\n", regd_buf);
  71                 return 1;
  72         }
  73 }
  74
  75 /**
  76  * iser_reg_single - fills registered buffer descriptor with
  77  *                   registration information
  78  */
  79 void iser_reg_single(struct iser_device *device,
  80                      struct iser_regd_buf *regd_buf,
  81                      enum dma_data_direction direction)
  82 {
  83         u64 dma_addr;
  84
  85         dma_addr = ib_dma_map_single(device->ib_device,
  86                                      regd_buf->virt_addr,
  87                                      regd_buf->data_size, direction);
  88         BUG_ON(ib_dma_mapping_error(device->ib_device, dma_addr));
  89
  90         regd_buf->reg.lkey = device->mr->lkey;
  91         regd_buf->reg.len  = regd_buf->data_size;
  92         regd_buf->reg.va   = dma_addr;
  93         regd_buf->reg.is_fmr = 0;
  94
  95         regd_buf->dma_addr  = dma_addr;
  96         regd_buf->direction = direction;
  97 }
  98
  99 /**
 100  * iser_start_rdma_unaligned_sg
 101  */
 102 static int iser_start_rdma_unaligned_sg(struct iscsi_iser_task *iser_task,
 103                                         enum iser_data_dir cmd_dir)
 104 {
 105         int dma_nents;
 106         struct ib_device *dev;
 107         char *mem = NULL;
 108         struct iser_data_buf *data = &iser_task->data[cmd_dir];
 109         unsigned long  cmd_data_len = data->data_len;
 110
 111         if (cmd_data_len > ISER_KMALLOC_THRESHOLD)
 112                 mem = (void *)__get_free_pages(GFP_NOIO,
 113                       ilog2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT);
 114         else
 115                 mem = kmalloc(cmd_data_len, GFP_NOIO);
 116
 117         if (mem == NULL) {
 118                 iser_err("Failed to allocate mem size %d %d for copying sglist\n",
 119                          data->size,(int)cmd_data_len);
 120                 return -ENOMEM;
 121         }
 122
 123         if (cmd_dir == ISER_DIR_OUT) {
 124                 /* copy the unaligned sg the buffer which is used for RDMA */
 125                 struct scatterlist *sgl = (struct scatterlist *)data->buf;
 126                 struct scatterlist *sg;
 127                 int i;
 128                 char *p, *from;
 129
 130                 p = mem;
 131                 for_each_sg(sgl, sg, data->size, i) {
 132                         from = kmap_atomic(sg_page(sg), KM_USER0);
 133                         memcpy(p,
 134                                from + sg->offset,
 135                                sg->length);
 136                         kunmap_atomic(from, KM_USER0);
 137                         p += sg->length;
 138                 }
 139         }
 140
 141         sg_init_one(&iser_task->data_copy[cmd_dir].sg_single, mem, cmd_data_len);
 142         iser_task->data_copy[cmd_dir].buf  =
 143                 &iser_task->data_copy[cmd_dir].sg_single;
 144         iser_task->data_copy[cmd_dir].size = 1;
 145
 146         iser_task->data_copy[cmd_dir].copy_buf  = mem;
 147
 148         dev = iser_task->iser_conn->ib_conn->device->ib_device;
 149         dma_nents = ib_dma_map_sg(dev,
 150                                   &iser_task->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_task->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_task *iser_task,
 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_task->iser_conn->ib_conn->device->ib_device;
 171         mem_copy = &iser_task->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 *sgl, *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                 sgl     = (struct scatterlist *)iser_task->data[ISER_DIR_IN].buf;
 188                 sg_size = iser_task->data[ISER_DIR_IN].size;
 189
 190                 p = mem;
 191                 for_each_sg(sgl, sg, sg_size, i) {
 192                         to = kmap_atomic(sg_page(sg), KM_SOFTIRQ0);
 193                         memcpy(to + sg->offset,
 194                                p,
 195                                sg->length);
 196                         kunmap_atomic(to, KM_SOFTIRQ0);
 197                         p += sg->length;
 198                 }
 199         }
 200
 201         cmd_data_len = iser_task->data[cmd_dir].data_len;
 202
 203         if (cmd_data_len > ISER_KMALLOC_THRESHOLD)
 204                 free_pages((unsigned long)mem_copy->copy_buf,
 205                            ilog2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT);
 206         else
 207                 kfree(mem_copy->copy_buf);
 208
 209         mem_copy->copy_buf = NULL;
 210 }
 211
 212 #define IS_4K_ALIGNED(addr)     ((((unsigned long)addr) & ~MASK_4K) == 0)
 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
 227 static int iser_sg_to_page_vec(struct iser_data_buf *data,
 228                                struct iser_page_vec *page_vec,
 229                                struct ib_device *ibdev)
 230 {
 231         struct scatterlist *sg, *sgl = (struct scatterlist *)data->buf;
 232         u64 start_addr, end_addr, page, chunk_start = 0;
 233         unsigned long total_sz = 0;
 234         unsigned int dma_len;
 235         int i, new_chunk, cur_page, last_ent = data->dma_nents - 1;
 236
 237         /* compute the offset of first element */
 238         page_vec->offset = (u64) sgl[0].offset & ~MASK_4K;
 239
 240         new_chunk = 1;
 241         cur_page  = 0;
 242         for_each_sg(sgl, sg, data->dma_nents, i) {
 243                 start_addr = ib_sg_dma_address(ibdev, sg);
 244                 if (new_chunk)
 245                         chunk_start = start_addr;
 246                 dma_len = ib_sg_dma_len(ibdev, sg);
 247                 end_addr = start_addr + dma_len;
 248                 total_sz += dma_len;
 249
 250                 /* collect page fragments until aligned or end of SG list */
 251                 if (!IS_4K_ALIGNED(end_addr) && i < last_ent) {
 252                         new_chunk = 0;
 253                         continue;
 254                 }
 255                 new_chunk = 1;
 256
 257                 /* address of the first page in the contiguous chunk;
 258                    masking relevant for the very first SG entry,
 259                    which might be unaligned */
 260                 page = chunk_start & MASK_4K;
 261                 do {
 262                         page_vec->pages[cur_page++] = page;
 263                         page += SIZE_4K;
 264                 } while (page < end_addr);
 265         }
 266
 267         page_vec->data_size = total_sz;
 268         iser_dbg("page_vec->data_size:%d cur_page %d\n", page_vec->data_size,cur_page);
 269         return cur_page;
 270 }
 271
 272
 273 /**
 274  * iser_data_buf_aligned_len - Tries to determine the maximal correctly aligned
 275  * for RDMA sub-list of a scatter-gather list of memory buffers, and  returns
 276  * the number of entries which are aligned correctly. Supports the case where
 277  * consecutive SG elements are actually fragments of the same physcial page.
 278  */
 279 static int iser_data_buf_aligned_len(struct iser_data_buf *data,
 280                                       struct ib_device *ibdev)
 281 {
 282         struct scatterlist *sgl, *sg, *next_sg = NULL;
 283         u64 start_addr, end_addr;
 284         int i, ret_len, start_check = 0;
 285
 286         if (data->dma_nents == 1)
 287                 return 1;
 288
 289         sgl = (struct scatterlist *)data->buf;
 290         start_addr  = ib_sg_dma_address(ibdev, sgl);
 291
 292         for_each_sg(sgl, sg, data->dma_nents, i) {
 293                 if (start_check && !IS_4K_ALIGNED(start_addr))
 294                         break;
 295
 296                 next_sg = sg_next(sg);
 297                 if (!next_sg)
 298                         break;
 299
 300                 end_addr    = start_addr + ib_sg_dma_len(ibdev, sg);
 301                 start_addr  = ib_sg_dma_address(ibdev, next_sg);
 302
 303                 if (end_addr == start_addr) {
 304                         start_check = 0;
 305                         continue;
 306                 } else
 307                         start_check = 1;
 308
 309                 if (!IS_4K_ALIGNED(end_addr))
 310                         break;
 311         }
 312         ret_len = (next_sg) ? i : i+1;
 313         iser_dbg("Found %d aligned entries out of %d in sg:0x%p\n",
 314                  ret_len, data->dma_nents, data);
 315         return ret_len;
 316 }
 317
 318 static void iser_data_buf_dump(struct iser_data_buf *data,
 319                                struct ib_device *ibdev)
 320 {
 321         struct scatterlist *sgl = (struct scatterlist *)data->buf;
 322         struct scatterlist *sg;
 323         int i;
 324
 325         if (iser_debug_level == 0)
 326                 return;
 327
 328         for_each_sg(sgl, sg, data->dma_nents, i)
 329                 iser_warn("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),
 332                          sg_page(sg), sg->offset,
 333                          sg->length, ib_sg_dma_len(ibdev, sg));
 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_task *iser_task,
 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_task->dir[iser_dir] = 1;
 377         dev = iser_task->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_task *iser_task)
 388 {
 389         struct ib_device *dev;
 390         struct iser_data_buf *data;
 391
 392         dev = iser_task->iser_conn->ib_conn->device->ib_device;
 393
 394         if (iser_task->dir[ISER_DIR_IN]) {
 395                 data = &iser_task->data[ISER_DIR_IN];
 396                 ib_dma_unmap_sg(dev, data->buf, data->size, DMA_FROM_DEVICE);
 397         }
 398
 399         if (iser_task->dir[ISER_DIR_OUT]) {
 400                 data = &iser_task->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_task *iser_task,
 412                       enum   iser_data_dir        cmd_dir)
 413 {
 414         struct iscsi_conn    *iscsi_conn = iser_task->iser_conn->iscsi_conn;
 415         struct iser_conn     *ib_conn = iser_task->iser_conn->ib_conn;
 416         struct iser_device   *device = ib_conn->device;
 417         struct ib_device     *ibdev = device->ib_device;
 418         struct iser_data_buf *mem = &iser_task->data[cmd_dir];
 419         struct iser_regd_buf *regd_buf;
 420         int aligned_len;
 421         int err;
 422         int i;
 423         struct scatterlist *sg;
 424
 425         regd_buf = &iser_task->rdma_regd[cmd_dir];
 426
 427         aligned_len = iser_data_buf_aligned_len(mem, ibdev);
 428         if (aligned_len != mem->dma_nents) {
 429                 iscsi_conn->fmr_unalign_cnt++;
 430                 iser_warn("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_task);
 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_task, cmd_dir) != 0)
 440                                 return -ENOMEM;
 441                 mem = &iser_task->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",
 466                                  mem->dma_nents,
 467                                  ntoh24(iser_task->desc.iscsi_header.dlength));
 468                         iser_err("page_vec: data_size = 0x%x, length = %d, offset = 0x%x\n",
 469                                  ib_conn->page_vec->data_size, ib_conn->page_vec->length,
 470                                  ib_conn->page_vec->offset);
 471                         for (i=0 ; i<ib_conn->page_vec->length ; i++)
 472                                 iser_err("page_vec[%d] = 0x%llx\n", i,
 473                                          (unsigned long long) ib_conn->page_vec->pages[i]);
 474                         return err;
 475                 }
 476         }
 477
 478         /* take a reference on this regd buf such that it will not be released *
 479          * (eg in send dto completion) before we get the scsi response         */
 480         atomic_inc(&regd_buf->ref_count);
 481         return 0;
 482 }