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