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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 <asm/io.h>
  39 #include <asm/scatterlist.h>
  40 #include <linux/scatterlist.h>
  41
  42 #include "iscsi_iser.h"
  43
  44 #define ISER_KMALLOC_THRESHOLD 0x20000 /* 128K - kmalloc limit */
  45
  46 /**
  47  * Decrements the reference count for the
  48  * registered buffer & releases it
  49  *
  50  * returns 0 if released, 1 if deferred
  51  */
  52 int iser_regd_buff_release(struct iser_regd_buf *regd_buf)
  53 {
  54         struct device *dma_device;
  55
  56         if ((atomic_read(&regd_buf->ref_count) == 0) ||
  57             atomic_dec_and_test(&regd_buf->ref_count)) {
  58                 /* if we used the dma mr, unreg is just NOP */
  59                 if (regd_buf->reg.is_fmr)
  60                         iser_unreg_mem(&regd_buf->reg);
  61
  62                 if (regd_buf->dma_addr) {
  63                         dma_device = regd_buf->device->ib_device->dma_device;
  64                         dma_unmap_single(dma_device,
  65                                          regd_buf->dma_addr,
  66                                          regd_buf->data_size,
  67                                          regd_buf->direction);
  68                 }
  69                 /* else this regd buf is associated with task which we */
  70                 /* dma_unmap_single/sg later */
  71                 return 0;
  72         } else {
  73                 iser_dbg("Release deferred, regd.buff: 0x%p\n", regd_buf);
  74                 return 1;
  75         }
  76 }
  77
  78 /**
  79  * iser_reg_single - fills registered buffer descriptor with
  80  *                   registration information
  81  */
  82 void iser_reg_single(struct iser_device *device,
  83                      struct iser_regd_buf *regd_buf,
  84                      enum dma_data_direction direction)
  85 {
  86         dma_addr_t dma_addr;
  87
  88         dma_addr  = dma_map_single(device->ib_device->dma_device,
  89                                    regd_buf->virt_addr,
  90                                    regd_buf->data_size, direction);
  91         BUG_ON(dma_mapping_error(dma_addr));
  92
  93         regd_buf->reg.lkey = device->mr->lkey;
  94         regd_buf->reg.len  = regd_buf->data_size;
  95         regd_buf->reg.va   = dma_addr;
  96         regd_buf->reg.is_fmr = 0;
  97
  98         regd_buf->dma_addr  = dma_addr;
  99         regd_buf->direction = direction;
 100 }
 101
 102 /**
 103  * iser_start_rdma_unaligned_sg
 104  */
 105 int iser_start_rdma_unaligned_sg(struct iscsi_iser_cmd_task  *iser_ctask,
 106                                  enum iser_data_dir cmd_dir)
 107 {
 108         int dma_nents;
 109         struct device *dma_device;
 110         char *mem = NULL;
 111         struct iser_data_buf *data = &iser_ctask->data[cmd_dir];
 112         unsigned long  cmd_data_len = data->data_len;
 113
 114         if (cmd_data_len > ISER_KMALLOC_THRESHOLD)
 115                 mem = (void *)__get_free_pages(GFP_NOIO,
 116                       long_log2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT);
 117         else
 118                 mem = kmalloc(cmd_data_len, GFP_NOIO);
 119
 120         if (mem == NULL) {
 121                 iser_err("Failed to allocate mem size %d %d for copying sglist\n",
 122                          data->size,(int)cmd_data_len);
 123                 return -ENOMEM;
 124         }
 125
 126         if (cmd_dir == ISER_DIR_OUT) {
 127                 /* copy the unaligned sg the buffer which is used for RDMA */
 128                 struct scatterlist *sg = (struct scatterlist *)data->buf;
 129                 int i;
 130                 char *p, *from;
 131
 132                 for (p = mem, i = 0; i < data->size; i++) {
 133                         from = kmap_atomic(sg[i].page, KM_USER0);
 134                         memcpy(p,
 135                                from + sg[i].offset,
 136                                sg[i].length);
 137                         kunmap_atomic(from, KM_USER0);
 138                         p += sg[i].length;
 139                 }
 140         }
 141
 142         sg_init_one(&iser_ctask->data_copy[cmd_dir].sg_single, mem, cmd_data_len);
 143         iser_ctask->data_copy[cmd_dir].buf  =
 144                 &iser_ctask->data_copy[cmd_dir].sg_single;
 145         iser_ctask->data_copy[cmd_dir].size = 1;
 146
 147         iser_ctask->data_copy[cmd_dir].copy_buf  = mem;
 148
 149         dma_device = iser_ctask->iser_conn->ib_conn->device->ib_device->dma_device;
 150
 151         if (cmd_dir == ISER_DIR_OUT)
 152                 dma_nents = dma_map_sg(dma_device,
 153                                        &iser_ctask->data_copy[cmd_dir].sg_single,
 154                                        1, DMA_TO_DEVICE);
 155         else
 156                 dma_nents = dma_map_sg(dma_device,
 157                                        &iser_ctask->data_copy[cmd_dir].sg_single,
 158                                        1, DMA_FROM_DEVICE);
 159
 160         BUG_ON(dma_nents == 0);
 161
 162         iser_ctask->data_copy[cmd_dir].dma_nents = dma_nents;
 163         return 0;
 164 }
 165
 166 /**
 167  * iser_finalize_rdma_unaligned_sg
 168  */
 169 void iser_finalize_rdma_unaligned_sg(struct iscsi_iser_cmd_task *iser_ctask,
 170                                      enum iser_data_dir         cmd_dir)
 171 {
 172         struct device *dma_device;
 173         struct iser_data_buf *mem_copy;
 174         unsigned long  cmd_data_len;
 175
 176         dma_device = iser_ctask->iser_conn->ib_conn->device->ib_device->dma_device;
 177         mem_copy   = &iser_ctask->data_copy[cmd_dir];
 178
 179         if (cmd_dir == ISER_DIR_OUT)
 180                 dma_unmap_sg(dma_device, &mem_copy->sg_single, 1,
 181                              DMA_TO_DEVICE);
 182         else
 183                 dma_unmap_sg(dma_device, &mem_copy->sg_single, 1,
 184                              DMA_FROM_DEVICE);
 185
 186         if (cmd_dir == ISER_DIR_IN) {
 187                 char *mem;
 188                 struct scatterlist *sg;
 189                 unsigned char *p, *to;
 190                 unsigned int sg_size;
 191                 int i;
 192
 193                 /* copy back read RDMA to unaligned sg */
 194                 mem     = mem_copy->copy_buf;
 195
 196                 sg      = (struct scatterlist *)iser_ctask->data[ISER_DIR_IN].buf;
 197                 sg_size = iser_ctask->data[ISER_DIR_IN].size;
 198
 199                 for (p = mem, i = 0; i < sg_size; i++){
 200                         to = kmap_atomic(sg[i].page, KM_SOFTIRQ0);
 201                         memcpy(to + sg[i].offset,
 202                                p,
 203                                sg[i].length);
 204                         kunmap_atomic(to, KM_SOFTIRQ0);
 205                         p += sg[i].length;
 206                 }
 207         }
 208
 209         cmd_data_len = iser_ctask->data[cmd_dir].data_len;
 210
 211         if (cmd_data_len > ISER_KMALLOC_THRESHOLD)
 212                 free_pages((unsigned long)mem_copy->copy_buf,
 213                            long_log2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT);
 214         else
 215                 kfree(mem_copy->copy_buf);
 216
 217         mem_copy->copy_buf = NULL;
 218 }
 219
 220 /**
 221  * iser_sg_to_page_vec - Translates scatterlist entries to physical addresses
 222  * and returns the length of resulting physical address array (may be less than
 223  * the original due to possible compaction).
 224  *
 225  * we build a "page vec" under the assumption that the SG meets the RDMA
 226  * alignment requirements. Other then the first and last SG elements, all
 227  * the "internal" elements can be compacted into a list whose elements are
 228  * dma addresses of physical pages. The code supports also the weird case
 229  * where --few fragments of the same page-- are present in the SG as
 230  * consecutive elements. Also, it handles one entry SG.
 231  */
 232 static int iser_sg_to_page_vec(struct iser_data_buf *data,
 233                                struct iser_page_vec *page_vec)
 234 {
 235         struct scatterlist *sg = (struct scatterlist *)data->buf;
 236         dma_addr_t first_addr, last_addr, page;
 237         int start_aligned, end_aligned;
 238         unsigned int cur_page = 0;
 239         unsigned long total_sz = 0;
 240         int i;
 241
 242         /* compute the offset of first element */
 243         page_vec->offset = (u64) sg[0].offset & ~MASK_4K;
 244
 245         for (i = 0; i < data->dma_nents; i++) {
 246                 total_sz += sg_dma_len(&sg[i]);
 247
 248                 first_addr = sg_dma_address(&sg[i]);
 249                 last_addr  = first_addr + sg_dma_len(&sg[i]);
 250
 251                 start_aligned = !(first_addr & ~MASK_4K);
 252                 end_aligned   = !(last_addr  & ~MASK_4K);
 253
 254                 /* continue to collect page fragments till aligned or SG ends */
 255                 while (!end_aligned && (i + 1 < data->dma_nents)) {
 256                         i++;
 257                         total_sz += sg_dma_len(&sg[i]);
 258                         last_addr = sg_dma_address(&sg[i]) + sg_dma_len(&sg[i]);
 259                         end_aligned = !(last_addr  & ~MASK_4K);
 260                 }
 261
 262                 /* handle the 1st page in the 1st DMA element */
 263                 if (cur_page == 0) {
 264                         page = first_addr & MASK_4K;
 265                         page_vec->pages[cur_page] = page;
 266                         cur_page++;
 267                         page += SIZE_4K;
 268                 } else
 269                         page = first_addr;
 270
 271                 for (; page < last_addr; page += SIZE_4K) {
 272                         page_vec->pages[cur_page] = page;
 273                         cur_page++;
 274                 }
 275
 276         }
 277         page_vec->data_size = total_sz;
 278         iser_dbg("page_vec->data_size:%d cur_page %d\n", page_vec->data_size,cur_page);
 279         return cur_page;
 280 }
 281
 282 #define IS_4K_ALIGNED(addr)     ((((unsigned long)addr) & ~MASK_4K) == 0)
 283
 284 /**
 285  * iser_data_buf_aligned_len - Tries to determine the maximal correctly aligned
 286  * for RDMA sub-list of a scatter-gather list of memory buffers, and  returns
 287  * the number of entries which are aligned correctly. Supports the case where
 288  * consecutive SG elements are actually fragments of the same physcial page.
 289  */
 290 static unsigned int iser_data_buf_aligned_len(struct iser_data_buf *data)
 291 {
 292         struct scatterlist *sg;
 293         dma_addr_t end_addr, next_addr;
 294         int i, cnt;
 295         unsigned int ret_len = 0;
 296
 297         sg = (struct scatterlist *)data->buf;
 298
 299         for (cnt = 0, i = 0; i < data->dma_nents; i++, cnt++) {
 300                 /* iser_dbg("Checking sg iobuf [%d]: phys=0x%08lX "
 301                    "offset: %ld sz: %ld\n", i,
 302                    (unsigned long)page_to_phys(sg[i].page),
 303                    (unsigned long)sg[i].offset,
 304                    (unsigned long)sg[i].length); */
 305                 end_addr = sg_dma_address(&sg[i]) +
 306                            sg_dma_len(&sg[i]);
 307                 /* iser_dbg("Checking sg iobuf end address "
 308                        "0x%08lX\n", end_addr); */
 309                 if (i + 1 < data->dma_nents) {
 310                         next_addr = sg_dma_address(&sg[i+1]);
 311                         /* are i, i+1 fragments of the same page? */
 312                         if (end_addr == next_addr)
 313                                 continue;
 314                         else if (!IS_4K_ALIGNED(end_addr)) {
 315                                 ret_len = cnt + 1;
 316                                 break;
 317                         }
 318                 }
 319         }
 320         if (i == data->dma_nents)
 321                 ret_len = cnt;  /* loop ended */
 322         iser_dbg("Found %d aligned entries out of %d in sg:0x%p\n",
 323                  ret_len, data->dma_nents, data);
 324         return ret_len;
 325 }
 326
 327 static void iser_data_buf_dump(struct iser_data_buf *data)
 328 {
 329         struct scatterlist *sg = (struct scatterlist *)data->buf;
 330         int i;
 331
 332         for (i = 0; i < data->dma_nents; i++)
 333                 iser_err("sg[%d] dma_addr:0x%lX page:0x%p "
 334                          "off:0x%x sz:0x%x dma_len:0x%x\n",
 335                          i, (unsigned long)sg_dma_address(&sg[i]),
 336                          sg[i].page, sg[i].offset,
 337                          sg[i].length,sg_dma_len(&sg[i]));
 338 }
 339
 340 static void iser_dump_page_vec(struct iser_page_vec *page_vec)
 341 {
 342         int i;
 343
 344         iser_err("page vec length %d data size %d\n",
 345                  page_vec->length, page_vec->data_size);
 346         for (i = 0; i < page_vec->length; i++)
 347                 iser_err("%d %lx\n",i,(unsigned long)page_vec->pages[i]);
 348 }
 349
 350 static void iser_page_vec_build(struct iser_data_buf *data,
 351                                 struct iser_page_vec *page_vec)
 352 {
 353         int page_vec_len = 0;
 354
 355         page_vec->length = 0;
 356         page_vec->offset = 0;
 357
 358         iser_dbg("Translating sg sz: %d\n", data->dma_nents);
 359         page_vec_len = iser_sg_to_page_vec(data,page_vec);
 360         iser_dbg("sg len %d page_vec_len %d\n", data->dma_nents,page_vec_len);
 361
 362         page_vec->length = page_vec_len;
 363
 364         if (page_vec_len * SIZE_4K < page_vec->data_size) {
 365                 iser_err("page_vec too short to hold this SG\n");
 366                 iser_data_buf_dump(data);
 367                 iser_dump_page_vec(page_vec);
 368                 BUG();
 369         }
 370 }
 371
 372 /**
 373  * iser_reg_rdma_mem - Registers memory intended for RDMA,
 374  * obtaining rkey and va
 375  *
 376  * returns 0 on success, errno code on failure
 377  */
 378 int iser_reg_rdma_mem(struct iscsi_iser_cmd_task *iser_ctask,
 379                       enum   iser_data_dir        cmd_dir)
 380 {
 381         struct iser_conn     *ib_conn = iser_ctask->iser_conn->ib_conn;
 382         struct iser_device   *device = ib_conn->device;
 383         struct iser_data_buf *mem = &iser_ctask->data[cmd_dir];
 384         struct iser_regd_buf *regd_buf;
 385         int aligned_len;
 386         int err;
 387         int i;
 388         struct scatterlist *sg;
 389
 390         regd_buf = &iser_ctask->rdma_regd[cmd_dir];
 391
 392         aligned_len = iser_data_buf_aligned_len(mem);
 393         if (aligned_len != mem->dma_nents) {
 394                 iser_err("rdma alignment violation %d/%d aligned\n",
 395                          aligned_len, mem->size);
 396                 iser_data_buf_dump(mem);
 397                 /* allocate copy buf, if we are writing, copy the */
 398                 /* unaligned scatterlist, dma map the copy        */
 399                 if (iser_start_rdma_unaligned_sg(iser_ctask, cmd_dir) != 0)
 400                                 return -ENOMEM;
 401                 mem = &iser_ctask->data_copy[cmd_dir];
 402         }
 403
 404         /* if there a single dma entry, FMR is not needed */
 405         if (mem->dma_nents == 1) {
 406                 sg = (struct scatterlist *)mem->buf;
 407
 408                 regd_buf->reg.lkey = device->mr->lkey;
 409                 regd_buf->reg.rkey = device->mr->rkey;
 410                 regd_buf->reg.len  = sg_dma_len(&sg[0]);
 411                 regd_buf->reg.va   = sg_dma_address(&sg[0]);
 412                 regd_buf->reg.is_fmr = 0;
 413
 414                 iser_dbg("PHYSICAL Mem.register: lkey: 0x%08X rkey: 0x%08X  "
 415                          "va: 0x%08lX sz: %ld]\n",
 416                          (unsigned int)regd_buf->reg.lkey,
 417                          (unsigned int)regd_buf->reg.rkey,
 418                          (unsigned long)regd_buf->reg.va,
 419                          (unsigned long)regd_buf->reg.len);
 420         } else { /* use FMR for multiple dma entries */
 421                 iser_page_vec_build(mem, ib_conn->page_vec);
 422                 err = iser_reg_page_vec(ib_conn, ib_conn->page_vec, &regd_buf->reg);
 423                 if (err) {
 424                         iser_data_buf_dump(mem);
 425                         iser_err("mem->dma_nents = %d (dlength = 0x%x)\n", mem->dma_nents,
 426                                  ntoh24(iser_ctask->desc.iscsi_header.dlength));
 427                         iser_err("page_vec: data_size = 0x%x, length = %d, offset = 0x%x\n",
 428                                  ib_conn->page_vec->data_size, ib_conn->page_vec->length,
 429                                  ib_conn->page_vec->offset);
 430                         for (i=0 ; i<ib_conn->page_vec->length ; i++)
 431                                 iser_err("page_vec[%d] = 0x%llx\n", i,
 432                                          (unsigned long long) ib_conn->page_vec->pages[i]);
 433                         return err;
 434                 }
 435         }
 436
 437         /* take a reference on this regd buf such that it will not be released *
 438          * (eg in send dto completion) before we get the scsi response         */
 439         atomic_inc(&regd_buf->ref_count);
 440         return 0;
 441 }