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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  * 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 device *dma_device;
  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.rkey != 0)
  59                         iser_unreg_mem(&regd_buf->reg);
  60
  61                 if (regd_buf->dma_addr) {
  62                         dma_device = regd_buf->device->ib_device->dma_device;
  63                         dma_unmap_single(dma_device,
  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         dma_addr_t dma_addr;
  86
  87         dma_addr  = dma_map_single(device->ib_device->dma_device,
  88                                    regd_buf->virt_addr,
  89                                    regd_buf->data_size, direction);
  90         BUG_ON(dma_mapping_error(dma_addr));
  91
  92         regd_buf->reg.lkey = device->mr->lkey;
  93         regd_buf->reg.rkey = 0; /* indicate there's no need to unreg */
  94         regd_buf->reg.len  = regd_buf->data_size;
  95         regd_buf->reg.va   = dma_addr;
  96
  97         regd_buf->dma_addr  = dma_addr;
  98         regd_buf->direction = direction;
  99 }
 100
 101 /**
 102  * iser_start_rdma_unaligned_sg
 103  */
 104 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 device *dma_device;
 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                       long_log2(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 *sg = (struct scatterlist *)data->buf;
 128                 int i;
 129                 char *p, *from;
 130
 131                 for (p = mem, i = 0; i < data->size; i++) {
 132                         from = kmap_atomic(sg[i].page, KM_USER0);
 133                         memcpy(p,
 134                                from + sg[i].offset,
 135                                sg[i].length);
 136                         kunmap_atomic(from, KM_USER0);
 137                         p += sg[i].length;
 138                 }
 139         }
 140
 141         sg_init_one(&iser_ctask->data_copy[cmd_dir].sg_single, mem, cmd_data_len);
 142         iser_ctask->data_copy[cmd_dir].buf  =
 143                 &iser_ctask->data_copy[cmd_dir].sg_single;
 144         iser_ctask->data_copy[cmd_dir].size = 1;
 145
 146         iser_ctask->data_copy[cmd_dir].copy_buf  = mem;
 147
 148         dma_device = iser_ctask->iser_conn->ib_conn->device->ib_device->dma_device;
 149
 150         if (cmd_dir == ISER_DIR_OUT)
 151                 dma_nents = dma_map_sg(dma_device,
 152                                        &iser_ctask->data_copy[cmd_dir].sg_single,
 153                                        1, DMA_TO_DEVICE);
 154         else
 155                 dma_nents = dma_map_sg(dma_device,
 156                                        &iser_ctask->data_copy[cmd_dir].sg_single,
 157                                        1, DMA_FROM_DEVICE);
 158
 159         BUG_ON(dma_nents == 0);
 160
 161         iser_ctask->data_copy[cmd_dir].dma_nents = dma_nents;
 162         return 0;
 163 }
 164
 165 /**
 166  * iser_finalize_rdma_unaligned_sg
 167  */
 168 void iser_finalize_rdma_unaligned_sg(struct iscsi_iser_cmd_task *iser_ctask,
 169                                      enum iser_data_dir         cmd_dir)
 170 {
 171         struct device *dma_device;
 172         struct iser_data_buf *mem_copy;
 173         unsigned long  cmd_data_len;
 174
 175         dma_device = iser_ctask->iser_conn->ib_conn->device->ib_device->dma_device;
 176         mem_copy   = &iser_ctask->data_copy[cmd_dir];
 177
 178         if (cmd_dir == ISER_DIR_OUT)
 179                 dma_unmap_sg(dma_device, &mem_copy->sg_single, 1,
 180                              DMA_TO_DEVICE);
 181         else
 182                 dma_unmap_sg(dma_device, &mem_copy->sg_single, 1,
 183                              DMA_FROM_DEVICE);
 184
 185         if (cmd_dir == ISER_DIR_IN) {
 186                 char *mem;
 187                 struct scatterlist *sg;
 188                 unsigned char *p, *to;
 189                 unsigned int sg_size;
 190                 int i;
 191
 192                 /* copy back read RDMA to unaligned sg */
 193                 mem     = mem_copy->copy_buf;
 194
 195                 sg      = (struct scatterlist *)iser_ctask->data[ISER_DIR_IN].buf;
 196                 sg_size = iser_ctask->data[ISER_DIR_IN].size;
 197
 198                 for (p = mem, i = 0; i < sg_size; i++){
 199                         to = kmap_atomic(sg[i].page, KM_SOFTIRQ0);
 200                         memcpy(to + sg[i].offset,
 201                                p,
 202                                sg[i].length);
 203                         kunmap_atomic(to, KM_SOFTIRQ0);
 204                         p += sg[i].length;
 205                 }
 206         }
 207
 208         cmd_data_len = iser_ctask->data[cmd_dir].data_len;
 209
 210         if (cmd_data_len > ISER_KMALLOC_THRESHOLD)
 211                 free_pages((unsigned long)mem_copy->copy_buf,
 212                            long_log2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT);
 213         else
 214                 kfree(mem_copy->copy_buf);
 215
 216         mem_copy->copy_buf = NULL;
 217 }
 218
 219 /**
 220  * iser_sg_to_page_vec - Translates scatterlist entries to physical addresses
 221  * and returns the length of resulting physical address array (may be less than
 222  * the original due to possible compaction).
 223  *
 224  * we build a "page vec" under the assumption that the SG meets the RDMA
 225  * alignment requirements. Other then the first and last SG elements, all
 226  * the "internal" elements can be compacted into a list whose elements are
 227  * dma addresses of physical pages. The code supports also the weird case
 228  * where --few fragments of the same page-- are present in the SG as
 229  * consecutive elements. Also, it handles one entry SG.
 230  */
 231 static int iser_sg_to_page_vec(struct iser_data_buf *data,
 232                                struct iser_page_vec *page_vec)
 233 {
 234         struct scatterlist *sg = (struct scatterlist *)data->buf;
 235         dma_addr_t first_addr, last_addr, page;
 236         int start_aligned, end_aligned;
 237         unsigned int cur_page = 0;
 238         unsigned long total_sz = 0;
 239         int i;
 240
 241         /* compute the offset of first element */
 242         page_vec->offset = (u64) sg[0].offset;
 243
 244         for (i = 0; i < data->dma_nents; i++) {
 245                 total_sz += sg_dma_len(&sg[i]);
 246
 247                 first_addr = sg_dma_address(&sg[i]);
 248                 last_addr  = first_addr + sg_dma_len(&sg[i]);
 249
 250                 start_aligned = !(first_addr & ~PAGE_MASK);
 251                 end_aligned   = !(last_addr  & ~PAGE_MASK);
 252
 253                 /* continue to collect page fragments till aligned or SG ends */
 254                 while (!end_aligned && (i + 1 < data->dma_nents)) {
 255                         i++;
 256                         total_sz += sg_dma_len(&sg[i]);
 257                         last_addr = sg_dma_address(&sg[i]) + sg_dma_len(&sg[i]);
 258                         end_aligned = !(last_addr  & ~PAGE_MASK);
 259                 }
 260
 261                 first_addr = first_addr & PAGE_MASK;
 262
 263                 for (page = first_addr; page < last_addr; page += PAGE_SIZE)
 264                         page_vec->pages[cur_page++] = page;
 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 #define MASK_4K                 ((1UL << 12) - 1) /* 0xFFF */
 273 #define IS_4K_ALIGNED(addr)     ((((unsigned long)addr) & MASK_4K) == 0)
 274
 275 /**
 276  * iser_data_buf_aligned_len - Tries to determine the maximal correctly aligned
 277  * for RDMA sub-list of a scatter-gather list of memory buffers, and  returns
 278  * the number of entries which are aligned correctly. Supports the case where
 279  * consecutive SG elements are actually fragments of the same physcial page.
 280  */
 281 static unsigned int iser_data_buf_aligned_len(struct iser_data_buf *data)
 282 {
 283         struct scatterlist *sg;
 284         dma_addr_t end_addr, next_addr;
 285         int i, cnt;
 286         unsigned int ret_len = 0;
 287
 288         sg = (struct scatterlist *)data->buf;
 289
 290         for (cnt = 0, i = 0; i < data->dma_nents; i++, cnt++) {
 291                 /* iser_dbg("Checking sg iobuf [%d]: phys=0x%08lX "
 292                    "offset: %ld sz: %ld\n", i,
 293                    (unsigned long)page_to_phys(sg[i].page),
 294                    (unsigned long)sg[i].offset,
 295                    (unsigned long)sg[i].length); */
 296                 end_addr = sg_dma_address(&sg[i]) +
 297                            sg_dma_len(&sg[i]);
 298                 /* iser_dbg("Checking sg iobuf end address "
 299                        "0x%08lX\n", end_addr); */
 300                 if (i + 1 < data->dma_nents) {
 301                         next_addr = sg_dma_address(&sg[i+1]);
 302                         /* are i, i+1 fragments of the same page? */
 303                         if (end_addr == next_addr)
 304                                 continue;
 305                         else if (!IS_4K_ALIGNED(end_addr)) {
 306                                 ret_len = cnt + 1;
 307                                 break;
 308                         }
 309                 }
 310         }
 311         if (i == data->dma_nents)
 312                 ret_len = cnt;  /* loop ended */
 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 {
 320         struct scatterlist *sg = (struct scatterlist *)data->buf;
 321         int i;
 322
 323         for (i = 0; i < data->size; i++)
 324                 iser_err("sg[%d] dma_addr:0x%lX page:0x%p "
 325                          "off:%d sz:%d dma_len:%d\n",
 326                          i, (unsigned long)sg_dma_address(&sg[i]),
 327                          sg[i].page, sg[i].offset,
 328                          sg[i].length,sg_dma_len(&sg[i]));
 329 }
 330
 331 static void iser_dump_page_vec(struct iser_page_vec *page_vec)
 332 {
 333         int i;
 334
 335         iser_err("page vec length %d data size %d\n",
 336                  page_vec->length, page_vec->data_size);
 337         for (i = 0; i < page_vec->length; i++)
 338                 iser_err("%d %lx\n",i,(unsigned long)page_vec->pages[i]);
 339 }
 340
 341 static void iser_page_vec_build(struct iser_data_buf *data,
 342                                 struct iser_page_vec *page_vec)
 343 {
 344         int page_vec_len = 0;
 345
 346         page_vec->length = 0;
 347         page_vec->offset = 0;
 348
 349         iser_dbg("Translating sg sz: %d\n", data->dma_nents);
 350         page_vec_len = iser_sg_to_page_vec(data,page_vec);
 351         iser_dbg("sg len %d page_vec_len %d\n", data->dma_nents,page_vec_len);
 352
 353         page_vec->length = page_vec_len;
 354
 355         if (page_vec_len * PAGE_SIZE < page_vec->data_size) {
 356                 iser_err("page_vec too short to hold this SG\n");
 357                 iser_data_buf_dump(data);
 358                 iser_dump_page_vec(page_vec);
 359                 BUG();
 360         }
 361 }
 362
 363 /**
 364  * iser_reg_rdma_mem - Registers memory intended for RDMA,
 365  * obtaining rkey and va
 366  *
 367  * returns 0 on success, errno code on failure
 368  */
 369 int iser_reg_rdma_mem(struct iscsi_iser_cmd_task *iser_ctask,
 370                       enum   iser_data_dir        cmd_dir)
 371 {
 372         struct iser_conn     *ib_conn = iser_ctask->iser_conn->ib_conn;
 373         struct iser_data_buf *mem = &iser_ctask->data[cmd_dir];
 374         struct iser_regd_buf *regd_buf;
 375         int aligned_len;
 376         int err;
 377
 378         regd_buf = &iser_ctask->rdma_regd[cmd_dir];
 379
 380         aligned_len = iser_data_buf_aligned_len(mem);
 381         if (aligned_len != mem->size) {
 382                 iser_err("rdma alignment violation %d/%d aligned\n",
 383                          aligned_len, mem->size);
 384                 iser_data_buf_dump(mem);
 385                 /* allocate copy buf, if we are writing, copy the */
 386                 /* unaligned scatterlist, dma map the copy        */
 387                 if (iser_start_rdma_unaligned_sg(iser_ctask, cmd_dir) != 0)
 388                                 return -ENOMEM;
 389                 mem = &iser_ctask->data_copy[cmd_dir];
 390         }
 391
 392         iser_page_vec_build(mem, ib_conn->page_vec);
 393         err = iser_reg_page_vec(ib_conn, ib_conn->page_vec, &regd_buf->reg);
 394         if (err)
 395                 return err;
 396
 397         /* take a reference on this regd buf such that it will not be released *
 398          * (eg in send dto completion) before we get the scsi response         */
 399         atomic_inc(&regd_buf->ref_count);
 400         return 0;
 401 }