net/rds/message.c

   1 /*
   2  * Copyright (c) 2006 Oracle.  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  */
  33 #include <linux/kernel.h>
  34 #include <linux/slab.h>
  35
  36 #include "rds.h"
  37
  38 static DECLARE_WAIT_QUEUE_HEAD(rds_message_flush_waitq);
  39
  40 static unsigned int     rds_exthdr_size[__RDS_EXTHDR_MAX] = {
  41 [RDS_EXTHDR_NONE]       = 0,
  42 [RDS_EXTHDR_VERSION]    = sizeof(struct rds_ext_header_version),
  43 [RDS_EXTHDR_RDMA]       = sizeof(struct rds_ext_header_rdma),
  44 [RDS_EXTHDR_RDMA_DEST]  = sizeof(struct rds_ext_header_rdma_dest),
  45 };
  46
  47
  48 void rds_message_addref(struct rds_message *rm)
  49 {
  50         rdsdebug("addref rm %p ref %d\n", rm, atomic_read(&rm->m_refcount));
  51         atomic_inc(&rm->m_refcount);
  52 }
  53 EXPORT_SYMBOL_GPL(rds_message_addref);
  54
  55 /*
  56  * This relies on dma_map_sg() not touching sg[].page during merging.
  57  */
  58 static void rds_message_purge(struct rds_message *rm)
  59 {
  60         unsigned long i;
  61
  62         if (unlikely(test_bit(RDS_MSG_PAGEVEC, &rm->m_flags)))
  63                 return;
  64
  65         for (i = 0; i < rm->data.m_nents; i++) {
  66                 rdsdebug("putting data page %p\n", (void *)sg_page(&rm->data.m_sg[i]));
  67                 /* XXX will have to put_page for page refs */
  68                 __free_page(sg_page(&rm->data.m_sg[i]));
  69         }
  70         rm->data.m_nents = 0;
  71
  72         if (rm->rdma.m_rdma_op.r_active)
  73                 rds_rdma_free_op(&rm->rdma.m_rdma_op);
  74         if (rm->rdma.m_rdma_mr)
  75                 rds_mr_put(rm->rdma.m_rdma_mr);
  76 }
  77
  78 void rds_message_put(struct rds_message *rm)
  79 {
  80         rdsdebug("put rm %p ref %d\n", rm, atomic_read(&rm->m_refcount));
  81
  82         if (atomic_dec_and_test(&rm->m_refcount)) {
  83                 BUG_ON(!list_empty(&rm->m_sock_item));
  84                 BUG_ON(!list_empty(&rm->m_conn_item));
  85                 rds_message_purge(rm);
  86
  87                 kfree(rm);
  88         }
  89 }
  90 EXPORT_SYMBOL_GPL(rds_message_put);
  91
  92 void rds_message_populate_header(struct rds_header *hdr, __be16 sport,
  93                                  __be16 dport, u64 seq)
  94 {
  95         hdr->h_flags = 0;
  96         hdr->h_sport = sport;
  97         hdr->h_dport = dport;
  98         hdr->h_sequence = cpu_to_be64(seq);
  99         hdr->h_exthdr[0] = RDS_EXTHDR_NONE;
 100 }
 101 EXPORT_SYMBOL_GPL(rds_message_populate_header);
 102
 103 int rds_message_add_extension(struct rds_header *hdr,
 104                 unsigned int type, const void *data, unsigned int len)
 105 {
 106         unsigned int ext_len = sizeof(u8) + len;
 107         unsigned char *dst;
 108
 109         /* For now, refuse to add more than one extension header */
 110         if (hdr->h_exthdr[0] != RDS_EXTHDR_NONE)
 111                 return 0;
 112
 113         if (type >= __RDS_EXTHDR_MAX || len != rds_exthdr_size[type])
 114                 return 0;
 115
 116         if (ext_len >= RDS_HEADER_EXT_SPACE)
 117                 return 0;
 118         dst = hdr->h_exthdr;
 119
 120         *dst++ = type;
 121         memcpy(dst, data, len);
 122
 123         dst[len] = RDS_EXTHDR_NONE;
 124         return 1;
 125 }
 126 EXPORT_SYMBOL_GPL(rds_message_add_extension);
 127
 128 /*
 129  * If a message has extension headers, retrieve them here.
 130  * Call like this:
 131  *
 132  * unsigned int pos = 0;
 133  *
 134  * while (1) {
 135  *      buflen = sizeof(buffer);
 136  *      type = rds_message_next_extension(hdr, &pos, buffer, &buflen);
 137  *      if (type == RDS_EXTHDR_NONE)
 138  *              break;
 139  *      ...
 140  * }
 141  */
 142 int rds_message_next_extension(struct rds_header *hdr,
 143                 unsigned int *pos, void *buf, unsigned int *buflen)
 144 {
 145         unsigned int offset, ext_type, ext_len;
 146         u8 *src = hdr->h_exthdr;
 147
 148         offset = *pos;
 149         if (offset >= RDS_HEADER_EXT_SPACE)
 150                 goto none;
 151
 152         /* Get the extension type and length. For now, the
 153          * length is implied by the extension type. */
 154         ext_type = src[offset++];
 155
 156         if (ext_type == RDS_EXTHDR_NONE || ext_type >= __RDS_EXTHDR_MAX)
 157                 goto none;
 158         ext_len = rds_exthdr_size[ext_type];
 159         if (offset + ext_len > RDS_HEADER_EXT_SPACE)
 160                 goto none;
 161
 162         *pos = offset + ext_len;
 163         if (ext_len < *buflen)
 164                 *buflen = ext_len;
 165         memcpy(buf, src + offset, *buflen);
 166         return ext_type;
 167
 168 none:
 169         *pos = RDS_HEADER_EXT_SPACE;
 170         *buflen = 0;
 171         return RDS_EXTHDR_NONE;
 172 }
 173
 174 int rds_message_add_version_extension(struct rds_header *hdr, unsigned int version)
 175 {
 176         struct rds_ext_header_version ext_hdr;
 177
 178         ext_hdr.h_version = cpu_to_be32(version);
 179         return rds_message_add_extension(hdr, RDS_EXTHDR_VERSION, &ext_hdr, sizeof(ext_hdr));
 180 }
 181
 182 int rds_message_get_version_extension(struct rds_header *hdr, unsigned int *version)
 183 {
 184         struct rds_ext_header_version ext_hdr;
 185         unsigned int pos = 0, len = sizeof(ext_hdr);
 186
 187         /* We assume the version extension is the only one present */
 188         if (rds_message_next_extension(hdr, &pos, &ext_hdr, &len) != RDS_EXTHDR_VERSION)
 189                 return 0;
 190         *version = be32_to_cpu(ext_hdr.h_version);
 191         return 1;
 192 }
 193
 194 int rds_message_add_rdma_dest_extension(struct rds_header *hdr, u32 r_key, u32 offset)
 195 {
 196         struct rds_ext_header_rdma_dest ext_hdr;
 197
 198         ext_hdr.h_rdma_rkey = cpu_to_be32(r_key);
 199         ext_hdr.h_rdma_offset = cpu_to_be32(offset);
 200         return rds_message_add_extension(hdr, RDS_EXTHDR_RDMA_DEST, &ext_hdr, sizeof(ext_hdr));
 201 }
 202 EXPORT_SYMBOL_GPL(rds_message_add_rdma_dest_extension);
 203
 204 /*
 205  * Each rds_message is allocated with extra space for the scatterlist entries
 206  * rds ops will need. This is to minimize memory allocation count. Then, each rds op
 207  * can grab SGs when initializing its part of the rds_message.
 208  */
 209 struct rds_message *rds_message_alloc(unsigned int extra_len, gfp_t gfp)
 210 {
 211         struct rds_message *rm;
 212
 213         rm = kzalloc(sizeof(struct rds_message) + extra_len, gfp);
 214         if (!rm)
 215                 goto out;
 216
 217         rm->m_used_sgs = 0;
 218         rm->m_total_sgs = extra_len / sizeof(struct scatterlist);
 219
 220         atomic_set(&rm->m_refcount, 1);
 221         INIT_LIST_HEAD(&rm->m_sock_item);
 222         INIT_LIST_HEAD(&rm->m_conn_item);
 223         spin_lock_init(&rm->m_rs_lock);
 224
 225 out:
 226         return rm;
 227 }
 228
 229 /*
 230  * RDS ops use this to grab SG entries from the rm's sg pool.
 231  */
 232 struct scatterlist *rds_message_alloc_sgs(struct rds_message *rm, int nents)
 233 {
 234         struct scatterlist *sg_first = (struct scatterlist *) &rm[1];
 235         struct scatterlist *sg_ret;
 236
 237         WARN_ON(rm->m_used_sgs + nents > rm->m_total_sgs);
 238
 239         sg_ret = &sg_first[rm->m_used_sgs];
 240         sg_init_table(sg_ret, nents);
 241         rm->m_used_sgs += nents;
 242
 243         return sg_ret;
 244 }
 245
 246 struct rds_message *rds_message_map_pages(unsigned long *page_addrs, unsigned int total_len)
 247 {
 248         struct rds_message *rm;
 249         unsigned int i;
 250         int num_sgs = ceil(total_len, PAGE_SIZE);
 251         int extra_bytes = num_sgs * sizeof(struct scatterlist);
 252
 253         rm = rds_message_alloc(extra_bytes, GFP_KERNEL);
 254         if (!rm)
 255                 return ERR_PTR(-ENOMEM);
 256
 257         set_bit(RDS_MSG_PAGEVEC, &rm->m_flags);
 258         rm->m_inc.i_hdr.h_len = cpu_to_be32(total_len);
 259         rm->data.m_nents = ceil(total_len, PAGE_SIZE);
 260         rm->data.m_sg = rds_message_alloc_sgs(rm, num_sgs);
 261
 262         for (i = 0; i < rm->data.m_nents; ++i) {
 263                 sg_set_page(&rm->data.m_sg[i],
 264                                 virt_to_page(page_addrs[i]),
 265                                 PAGE_SIZE, 0);
 266         }
 267
 268         return rm;
 269 }
 270
 271 int rds_message_copy_from_user(struct rds_message *rm, struct iovec *first_iov,
 272                                                size_t total_len)
 273 {
 274         unsigned long to_copy;
 275         unsigned long iov_off;
 276         unsigned long sg_off;
 277         struct iovec *iov;
 278         struct scatterlist *sg;
 279         int ret = 0;
 280
 281         rm->m_inc.i_hdr.h_len = cpu_to_be32(total_len);
 282
 283         /*
 284          * now allocate and copy in the data payload.
 285          */
 286         sg = rm->data.m_sg;
 287         iov = first_iov;
 288         iov_off = 0;
 289         sg_off = 0; /* Dear gcc, sg->page will be null from kzalloc. */
 290
 291         while (total_len) {
 292                 if (!sg_page(sg)) {
 293                         ret = rds_page_remainder_alloc(sg, total_len,
 294                                                        GFP_HIGHUSER);
 295                         if (ret)
 296                                 goto out;
 297                         rm->data.m_nents++;
 298                         sg_off = 0;
 299                 }
 300
 301                 while (iov_off == iov->iov_len) {
 302                         iov_off = 0;
 303                         iov++;
 304                 }
 305
 306                 to_copy = min(iov->iov_len - iov_off, sg->length - sg_off);
 307                 to_copy = min_t(size_t, to_copy, total_len);
 308
 309                 rdsdebug("copying %lu bytes from user iov [%p, %zu] + %lu to "
 310                          "sg [%p, %u, %u] + %lu\n",
 311                          to_copy, iov->iov_base, iov->iov_len, iov_off,
 312                          (void *)sg_page(sg), sg->offset, sg->length, sg_off);
 313
 314                 ret = rds_page_copy_from_user(sg_page(sg), sg->offset + sg_off,
 315                                               iov->iov_base + iov_off,
 316                                               to_copy);
 317                 if (ret)
 318                         goto out;
 319
 320                 iov_off += to_copy;
 321                 total_len -= to_copy;
 322                 sg_off += to_copy;
 323
 324                 if (sg_off == sg->length)
 325                         sg++;
 326         }
 327
 328 out:
 329         return ret;
 330 }
 331
 332 int rds_message_inc_copy_to_user(struct rds_incoming *inc,
 333                                  struct iovec *first_iov, size_t size)
 334 {
 335         struct rds_message *rm;
 336         struct iovec *iov;
 337         struct scatterlist *sg;
 338         unsigned long to_copy;
 339         unsigned long iov_off;
 340         unsigned long vec_off;
 341         int copied;
 342         int ret;
 343         u32 len;
 344
 345         rm = container_of(inc, struct rds_message, m_inc);
 346         len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
 347
 348         iov = first_iov;
 349         iov_off = 0;
 350         sg = rm->data.m_sg;
 351         vec_off = 0;
 352         copied = 0;
 353
 354         while (copied < size && copied < len) {
 355                 while (iov_off == iov->iov_len) {
 356                         iov_off = 0;
 357                         iov++;
 358                 }
 359
 360                 to_copy = min(iov->iov_len - iov_off, sg->length - vec_off);
 361                 to_copy = min_t(size_t, to_copy, size - copied);
 362                 to_copy = min_t(unsigned long, to_copy, len - copied);
 363
 364                 rdsdebug("copying %lu bytes to user iov [%p, %zu] + %lu to "
 365                          "sg [%p, %u, %u] + %lu\n",
 366                          to_copy, iov->iov_base, iov->iov_len, iov_off,
 367                          sg_page(sg), sg->offset, sg->length, vec_off);
 368
 369                 ret = rds_page_copy_to_user(sg_page(sg), sg->offset + vec_off,
 370                                             iov->iov_base + iov_off,
 371                                             to_copy);
 372                 if (ret) {
 373                         copied = ret;
 374                         break;
 375                 }
 376
 377                 iov_off += to_copy;
 378                 vec_off += to_copy;
 379                 copied += to_copy;
 380
 381                 if (vec_off == sg->length) {
 382                         vec_off = 0;
 383                         sg++;
 384                 }
 385         }
 386
 387         return copied;
 388 }
 389
 390 /*
 391  * If the message is still on the send queue, wait until the transport
 392  * is done with it. This is particularly important for RDMA operations.
 393  */
 394 void rds_message_wait(struct rds_message *rm)
 395 {
 396         wait_event(rds_message_flush_waitq,
 397                         !test_bit(RDS_MSG_MAPPED, &rm->m_flags));
 398 }
 399
 400 void rds_message_unmapped(struct rds_message *rm)
 401 {
 402         clear_bit(RDS_MSG_MAPPED, &rm->m_flags);
 403         if (waitqueue_active(&rds_message_flush_waitq))
 404                 wake_up(&rds_message_flush_waitq);
 405 }
 406 EXPORT_SYMBOL_GPL(rds_message_unmapped);
 407