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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 <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 device *dma_device;
  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                         dma_device = regd_buf->device->ib_device->dma_device;
  65                         dma_unmap_single(dma_device,
  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         dma_addr_t dma_addr;
  88
  89         dma_addr  = dma_map_single(device->ib_device->dma_device,
  90                                    regd_buf->virt_addr,
  91                                    regd_buf->data_size, direction);
  92         BUG_ON(dma_mapping_error(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 device *dma_device;
 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                       long_log2(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         dma_device = iser_ctask->iser_conn->ib_conn->device->ib_device->dma_device;
 151
 152         if (cmd_dir == ISER_DIR_OUT)
 153                 dma_nents = dma_map_sg(dma_device,
 154                                        &iser_ctask->data_copy[cmd_dir].sg_single,
 155                                        1, DMA_TO_DEVICE);
 156         else
 157                 dma_nents = dma_map_sg(dma_device,
 158                                        &iser_ctask->data_copy[cmd_dir].sg_single,
 159                                        1, DMA_FROM_DEVICE);
 160
 161         BUG_ON(dma_nents == 0);
 162
 163         iser_ctask->data_copy[cmd_dir].dma_nents = dma_nents;
 164         return 0;
 165 }
 166
 167 /**
 168  * iser_finalize_rdma_unaligned_sg
 169  */
 170 void iser_finalize_rdma_unaligned_sg(struct iscsi_iser_cmd_task *iser_ctask,
 171                                      enum iser_data_dir         cmd_dir)
 172 {
 173         struct device *dma_device;
 174         struct iser_data_buf *mem_copy;
 175         unsigned long  cmd_data_len;
 176
 177         dma_device = iser_ctask->iser_conn->ib_conn->device->ib_device->dma_device;
 178         mem_copy   = &iser_ctask->data_copy[cmd_dir];
 179
 180         if (cmd_dir == ISER_DIR_OUT)
 181                 dma_unmap_sg(dma_device, &mem_copy->sg_single, 1,
 182                              DMA_TO_DEVICE);
 183         else
 184                 dma_unmap_sg(dma_device, &mem_copy->sg_single, 1,
 185                              DMA_FROM_DEVICE);
 186
 187         if (cmd_dir == ISER_DIR_IN) {
 188                 char *mem;
 189                 struct scatterlist *sg;
 190                 unsigned char *p, *to;
 191                 unsigned int sg_size;
 192                 int i;
 193
 194                 /* copy back read RDMA to unaligned sg */
 195                 mem     = mem_copy->copy_buf;
 196
 197                 sg      = (struct scatterlist *)iser_ctask->data[ISER_DIR_IN].buf;
 198                 sg_size = iser_ctask->data[ISER_DIR_IN].size;
 199
 200                 for (p = mem, i = 0; i < sg_size; i++){
 201                         to = kmap_atomic(sg[i].page, KM_SOFTIRQ0);
 202                         memcpy(to + sg[i].offset,
 203                                p,
 204                                sg[i].length);
 205                         kunmap_atomic(to, KM_SOFTIRQ0);
 206                         p += sg[i].length;
 207                 }
 208         }
 209
 210         cmd_data_len = iser_ctask->data[cmd_dir].data_len;
 211
 212         if (cmd_data_len > ISER_KMALLOC_THRESHOLD)
 213                 free_pages((unsigned long)mem_copy->copy_buf,
 214                            long_log2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT);
 215         else
 216                 kfree(mem_copy->copy_buf);
 217
 218         mem_copy->copy_buf = NULL;
 219 }
 220
 221 /**
 222  * iser_sg_to_page_vec - Translates scatterlist entries to physical addresses
 223  * and returns the length of resulting physical address array (may be less than
 224  * the original due to possible compaction).
 225  *
 226  * we build a "page vec" under the assumption that the SG meets the RDMA
 227  * alignment requirements. Other then the first and last SG elements, all
 228  * the "internal" elements can be compacted into a list whose elements are
 229  * dma addresses of physical pages. The code supports also the weird case
 230  * where --few fragments of the same page-- are present in the SG as
 231  * consecutive elements. Also, it handles one entry SG.
 232  */
 233 static int iser_sg_to_page_vec(struct iser_data_buf *data,
 234                                struct iser_page_vec *page_vec)
 235 {
 236         struct scatterlist *sg = (struct scatterlist *)data->buf;
 237         dma_addr_t first_addr, last_addr, page;
 238         int start_aligned, end_aligned;
 239         unsigned int cur_page = 0;
 240         unsigned long total_sz = 0;
 241         int i;
 242
 243         /* compute the offset of first element */
 244         page_vec->offset = (u64) sg[0].offset & ~MASK_4K;
 245
 246         for (i = 0; i < data->dma_nents; i++) {
 247                 total_sz += sg_dma_len(&sg[i]);
 248
 249                 first_addr = sg_dma_address(&sg[i]);
 250                 last_addr  = first_addr + sg_dma_len(&sg[i]);
 251
 252                 start_aligned = !(first_addr & ~MASK_4K);
 253                 end_aligned   = !(last_addr  & ~MASK_4K);
 254
 255                 /* continue to collect page fragments till aligned or SG ends */
 256                 while (!end_aligned && (i + 1 < data->dma_nents)) {
 257                         i++;
 258                         total_sz += sg_dma_len(&sg[i]);
 259                         last_addr = sg_dma_address(&sg[i]) + sg_dma_len(&sg[i]);
 260                         end_aligned = !(last_addr  & ~MASK_4K);
 261                 }
 262
 263                 /* handle the 1st page in the 1st DMA element */
 264                 if (cur_page == 0) {
 265                         page = first_addr & MASK_4K;
 266                         page_vec->pages[cur_page] = page;
 267                         cur_page++;
 268                         page += SIZE_4K;
 269                 } else
 270                         page = first_addr;
 271
 272                 for (; page < last_addr; page += SIZE_4K) {
 273                         page_vec->pages[cur_page] = page;
 274                         cur_page++;
 275                 }
 276
 277         }
 278         page_vec->data_size = total_sz;
 279         iser_dbg("page_vec->data_size:%d cur_page %d\n", page_vec->data_size,cur_page);
 280         return cur_page;
 281 }
 282
 283 #define IS_4K_ALIGNED(addr)     ((((unsigned long)addr) & ~MASK_4K) == 0)
 284
 285 /**
 286  * iser_data_buf_aligned_len - Tries to determine the maximal correctly aligned
 287  * for RDMA sub-list of a scatter-gather list of memory buffers, and  returns
 288  * the number of entries which are aligned correctly. Supports the case where
 289  * consecutive SG elements are actually fragments of the same physcial page.
 290  */
 291 static unsigned int iser_data_buf_aligned_len(struct iser_data_buf *data)
 292 {
 293         struct scatterlist *sg;
 294         dma_addr_t end_addr, next_addr;
 295         int i, cnt;
 296         unsigned int ret_len = 0;
 297
 298         sg = (struct scatterlist *)data->buf;
 299
 300         for (cnt = 0, i = 0; i < data->dma_nents; i++, cnt++) {
 301                 /* iser_dbg("Checking sg iobuf [%d]: phys=0x%08lX "
 302                    "offset: %ld sz: %ld\n", i,
 303                    (unsigned long)page_to_phys(sg[i].page),
 304                    (unsigned long)sg[i].offset,
 305                    (unsigned long)sg[i].length); */
 306                 end_addr = sg_dma_address(&sg[i]) +
 307                            sg_dma_len(&sg[i]);
 308                 /* iser_dbg("Checking sg iobuf end address "
 309                        "0x%08lX\n", end_addr); */
 310                 if (i + 1 < data->dma_nents) {
 311                         next_addr = sg_dma_address(&sg[i+1]);
 312                         /* are i, i+1 fragments of the same page? */
 313                         if (end_addr == next_addr)
 314                                 continue;
 315                         else if (!IS_4K_ALIGNED(end_addr)) {
 316                                 ret_len = cnt + 1;
 317                                 break;
 318                         }
 319                 }
 320         }
 321         if (i == data->dma_nents)
 322                 ret_len = cnt;  /* loop ended */
 323         iser_dbg("Found %d aligned entries out of %d in sg:0x%p\n",
 324                  ret_len, data->dma_nents, data);
 325         return ret_len;
 326 }
 327
 328 static void iser_data_buf_dump(struct iser_data_buf *data)
 329 {
 330         struct scatterlist *sg = (struct scatterlist *)data->buf;
 331         int i;
 332
 333         for (i = 0; i < data->dma_nents; i++)
 334                 iser_err("sg[%d] dma_addr:0x%lX page:0x%p "
 335                          "off:0x%x sz:0x%x dma_len:0x%x\n",
 336                          i, (unsigned long)sg_dma_address(&sg[i]),
 337                          sg[i].page, sg[i].offset,
 338                          sg[i].length,sg_dma_len(&sg[i]));
 339 }
 340
 341 static void iser_dump_page_vec(struct iser_page_vec *page_vec)
 342 {
 343         int i;
 344
 345         iser_err("page vec length %d data size %d\n",
 346                  page_vec->length, page_vec->data_size);
 347         for (i = 0; i < page_vec->length; i++)
 348                 iser_err("%d %lx\n",i,(unsigned long)page_vec->pages[i]);
 349 }
 350
 351 static void iser_page_vec_build(struct iser_data_buf *data,
 352                                 struct iser_page_vec *page_vec)
 353 {
 354         int page_vec_len = 0;
 355
 356         page_vec->length = 0;
 357         page_vec->offset = 0;
 358
 359         iser_dbg("Translating sg sz: %d\n", data->dma_nents);
 360         page_vec_len = iser_sg_to_page_vec(data,page_vec);
 361         iser_dbg("sg len %d page_vec_len %d\n", data->dma_nents,page_vec_len);
 362
 363         page_vec->length = page_vec_len;
 364
 365         if (page_vec_len * SIZE_4K < page_vec->data_size) {
 366                 iser_err("page_vec too short to hold this SG\n");
 367                 iser_data_buf_dump(data);
 368                 iser_dump_page_vec(page_vec);
 369                 BUG();
 370         }
 371 }
 372
 373 int iser_dma_map_task_data(struct iscsi_iser_cmd_task *iser_ctask,
 374                             struct iser_data_buf       *data,
 375                             enum   iser_data_dir       iser_dir,
 376                             enum   dma_data_direction  dma_dir)
 377 {
 378         struct device *dma_device;
 379
 380         iser_ctask->dir[iser_dir] = 1;
 381         dma_device =
 382                 iser_ctask->iser_conn->ib_conn->device->ib_device->dma_device;
 383
 384         data->dma_nents = dma_map_sg(dma_device, data->buf, data->size, dma_dir);
 385         if (data->dma_nents == 0) {
 386                 iser_err("dma_map_sg failed!!!\n");
 387                 return -EINVAL;
 388         }
 389         return 0;
 390 }
 391
 392 void iser_dma_unmap_task_data(struct iscsi_iser_cmd_task *iser_ctask)
 393 {
 394         struct device  *dma_device;
 395         struct iser_data_buf *data;
 396
 397         dma_device =
 398                 iser_ctask->iser_conn->ib_conn->device->ib_device->dma_device;
 399
 400         if (iser_ctask->dir[ISER_DIR_IN]) {
 401                 data = &iser_ctask->data[ISER_DIR_IN];
 402                 dma_unmap_sg(dma_device, data->buf, data->size, DMA_FROM_DEVICE);
 403         }
 404
 405         if (iser_ctask->dir[ISER_DIR_OUT]) {
 406                 data = &iser_ctask->data[ISER_DIR_OUT];
 407                 dma_unmap_sg(dma_device, data->buf, data->size, DMA_TO_DEVICE);
 408         }
 409 }
 410
 411 /**
 412  * iser_reg_rdma_mem - Registers memory intended for RDMA,
 413  * obtaining rkey and va
 414  *
 415  * returns 0 on success, errno code on failure
 416  */
 417 int iser_reg_rdma_mem(struct iscsi_iser_cmd_task *iser_ctask,
 418                       enum   iser_data_dir        cmd_dir)
 419 {
 420         struct iser_conn     *ib_conn = iser_ctask->iser_conn->ib_conn;
 421         struct iser_device   *device = ib_conn->device;
 422         struct iser_data_buf *mem = &iser_ctask->data[cmd_dir];
 423         struct iser_regd_buf *regd_buf;
 424         int aligned_len;
 425         int err;
 426         int i;
 427         struct scatterlist *sg;
 428
 429         regd_buf = &iser_ctask->rdma_regd[cmd_dir];
 430
 431         aligned_len = iser_data_buf_aligned_len(mem);
 432         if (aligned_len != mem->dma_nents) {
 433                 iser_err("rdma alignment violation %d/%d aligned\n",
 434                          aligned_len, mem->size);
 435                 iser_data_buf_dump(mem);
 436
 437                 /* unmap the command data before accessing it */
 438                 iser_dma_unmap_task_data(iser_ctask);
 439
 440                 /* allocate copy buf, if we are writing, copy the */
 441                 /* unaligned scatterlist, dma map the copy        */
 442                 if (iser_start_rdma_unaligned_sg(iser_ctask, cmd_dir) != 0)
 443                                 return -ENOMEM;
 444                 mem = &iser_ctask->data_copy[cmd_dir];
 445         }
 446
 447         /* if there a single dma entry, FMR is not needed */
 448         if (mem->dma_nents == 1) {
 449                 sg = (struct scatterlist *)mem->buf;
 450
 451                 regd_buf->reg.lkey = device->mr->lkey;
 452                 regd_buf->reg.rkey = device->mr->rkey;
 453                 regd_buf->reg.len  = sg_dma_len(&sg[0]);
 454                 regd_buf->reg.va   = sg_dma_address(&sg[0]);
 455                 regd_buf->reg.is_fmr = 0;
 456
 457                 iser_dbg("PHYSICAL Mem.register: lkey: 0x%08X rkey: 0x%08X  "
 458                          "va: 0x%08lX sz: %ld]\n",
 459                          (unsigned int)regd_buf->reg.lkey,
 460                          (unsigned int)regd_buf->reg.rkey,
 461                          (unsigned long)regd_buf->reg.va,
 462                          (unsigned long)regd_buf->reg.len);
 463         } else { /* use FMR for multiple dma entries */
 464                 iser_page_vec_build(mem, ib_conn->page_vec);
 465                 err = iser_reg_page_vec(ib_conn, ib_conn->page_vec, &regd_buf->reg);
 466                 if (err) {
 467                         iser_data_buf_dump(mem);
 468                         iser_err("mem->dma_nents = %d (dlength = 0x%x)\n", mem->dma_nents,
 469                                  ntoh24(iser_ctask->desc.iscsi_header.dlength));
 470                         iser_err("page_vec: data_size = 0x%x, length = %d, offset = 0x%x\n",
 471                                  ib_conn->page_vec->data_size, ib_conn->page_vec->length,
 472                                  ib_conn->page_vec->offset);
 473                         for (i=0 ; i<ib_conn->page_vec->length ; i++)
 474                                 iser_err("page_vec[%d] = 0x%llx\n", i,
 475                                          (unsigned long long) ib_conn->page_vec->pages[i]);
 476                         return err;
 477                 }
 478         }
 479
 480         /* take a reference on this regd buf such that it will not be released *
 481          * (eg in send dto completion) before we get the scsi response         */
 482         atomic_inc(&regd_buf->ref_count);
 483         return 0;
 484 }