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 #include <linux/export.h>
  36
  37 #include "rds.h"
  38
  39 static unsigned int     rds_exthdr_size[__RDS_EXTHDR_MAX] = {
  40 [RDS_EXTHDR_NONE]       = 0,
  41 [RDS_EXTHDR_VERSION]    = sizeof(struct rds_ext_header_version),
  42 [RDS_EXTHDR_RDMA]       = sizeof(struct rds_ext_header_rdma),
  43 [RDS_EXTHDR_RDMA_DEST]  = sizeof(struct rds_ext_header_rdma_dest),
  44 [RDS_EXTHDR_NPATHS]     = sizeof(u16),
  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.op_nents; i++) {
  66                 rdsdebug("putting data page %p\n", (void *)sg_page(&rm->data.op_sg[i]));
  67                 /* XXX will have to put_page for page refs */
  68                 __free_page(sg_page(&rm->data.op_sg[i]));
  69         }
  70         rm->data.op_nents = 0;
  71
  72         if (rm->rdma.op_active)
  73                 rds_rdma_free_op(&rm->rdma);
  74         if (rm->rdma.op_rdma_mr)
  75                 rds_mr_put(rm->rdma.op_rdma_mr);
  76
  77         if (rm->atomic.op_active)
  78                 rds_atomic_free_op(&rm->atomic);
  79         if (rm->atomic.op_rdma_mr)
  80                 rds_mr_put(rm->atomic.op_rdma_mr);
  81 }
  82
  83 void rds_message_put(struct rds_message *rm)
  84 {
  85         rdsdebug("put rm %p ref %d\n", rm, atomic_read(&rm->m_refcount));
  86         WARN(!atomic_read(&rm->m_refcount), "danger refcount zero on %p\n", rm);
  87         if (atomic_dec_and_test(&rm->m_refcount)) {
  88                 BUG_ON(!list_empty(&rm->m_sock_item));
  89                 BUG_ON(!list_empty(&rm->m_conn_item));
  90                 rds_message_purge(rm);
  91
  92                 kfree(rm);
  93         }
  94 }
  95 EXPORT_SYMBOL_GPL(rds_message_put);
  96
  97 void rds_message_populate_header(struct rds_header *hdr, __be16 sport,
  98                                  __be16 dport, u64 seq)
  99 {
 100         hdr->h_flags = 0;
 101         hdr->h_sport = sport;
 102         hdr->h_dport = dport;
 103         hdr->h_sequence = cpu_to_be64(seq);
 104         hdr->h_exthdr[0] = RDS_EXTHDR_NONE;
 105 }
 106 EXPORT_SYMBOL_GPL(rds_message_populate_header);
 107
 108 int rds_message_add_extension(struct rds_header *hdr, unsigned int type,
 109                               const void *data, unsigned int len)
 110 {
 111         unsigned int ext_len = sizeof(u8) + len;
 112         unsigned char *dst;
 113
 114         /* For now, refuse to add more than one extension header */
 115         if (hdr->h_exthdr[0] != RDS_EXTHDR_NONE)
 116                 return 0;
 117
 118         if (type >= __RDS_EXTHDR_MAX || len != rds_exthdr_size[type])
 119                 return 0;
 120
 121         if (ext_len >= RDS_HEADER_EXT_SPACE)
 122                 return 0;
 123         dst = hdr->h_exthdr;
 124
 125         *dst++ = type;
 126         memcpy(dst, data, len);
 127
 128         dst[len] = RDS_EXTHDR_NONE;
 129         return 1;
 130 }
 131 EXPORT_SYMBOL_GPL(rds_message_add_extension);
 132
 133 /*
 134  * If a message has extension headers, retrieve them here.
 135  * Call like this:
 136  *
 137  * unsigned int pos = 0;
 138  *
 139  * while (1) {
 140  *      buflen = sizeof(buffer);
 141  *      type = rds_message_next_extension(hdr, &pos, buffer, &buflen);
 142  *      if (type == RDS_EXTHDR_NONE)
 143  *              break;
 144  *      ...
 145  * }
 146  */
 147 int rds_message_next_extension(struct rds_header *hdr,
 148                 unsigned int *pos, void *buf, unsigned int *buflen)
 149 {
 150         unsigned int offset, ext_type, ext_len;
 151         u8 *src = hdr->h_exthdr;
 152
 153         offset = *pos;
 154         if (offset >= RDS_HEADER_EXT_SPACE)
 155                 goto none;
 156
 157         /* Get the extension type and length. For now, the
 158          * length is implied by the extension type. */
 159         ext_type = src[offset++];
 160
 161         if (ext_type == RDS_EXTHDR_NONE || ext_type >= __RDS_EXTHDR_MAX)
 162                 goto none;
 163         ext_len = rds_exthdr_size[ext_type];
 164         if (offset + ext_len > RDS_HEADER_EXT_SPACE)
 165                 goto none;
 166
 167         *pos = offset + ext_len;
 168         if (ext_len < *buflen)
 169                 *buflen = ext_len;
 170         memcpy(buf, src + offset, *buflen);
 171         return ext_type;
 172
 173 none:
 174         *pos = RDS_HEADER_EXT_SPACE;
 175         *buflen = 0;
 176         return RDS_EXTHDR_NONE;
 177 }
 178
 179 int rds_message_add_rdma_dest_extension(struct rds_header *hdr, u32 r_key, u32 offset)
 180 {
 181         struct rds_ext_header_rdma_dest ext_hdr;
 182
 183         ext_hdr.h_rdma_rkey = cpu_to_be32(r_key);
 184         ext_hdr.h_rdma_offset = cpu_to_be32(offset);
 185         return rds_message_add_extension(hdr, RDS_EXTHDR_RDMA_DEST, &ext_hdr, sizeof(ext_hdr));
 186 }
 187 EXPORT_SYMBOL_GPL(rds_message_add_rdma_dest_extension);
 188
 189 /*
 190  * Each rds_message is allocated with extra space for the scatterlist entries
 191  * rds ops will need. This is to minimize memory allocation count. Then, each rds op
 192  * can grab SGs when initializing its part of the rds_message.
 193  */
 194 struct rds_message *rds_message_alloc(unsigned int extra_len, gfp_t gfp)
 195 {
 196         struct rds_message *rm;
 197
 198         if (extra_len > KMALLOC_MAX_SIZE - sizeof(struct rds_message))
 199                 return NULL;
 200
 201         rm = kzalloc(sizeof(struct rds_message) + extra_len, gfp);
 202         if (!rm)
 203                 goto out;
 204
 205         rm->m_used_sgs = 0;
 206         rm->m_total_sgs = extra_len / sizeof(struct scatterlist);
 207
 208         atomic_set(&rm->m_refcount, 1);
 209         INIT_LIST_HEAD(&rm->m_sock_item);
 210         INIT_LIST_HEAD(&rm->m_conn_item);
 211         spin_lock_init(&rm->m_rs_lock);
 212         init_waitqueue_head(&rm->m_flush_wait);
 213
 214 out:
 215         return rm;
 216 }
 217
 218 /*
 219  * RDS ops use this to grab SG entries from the rm's sg pool.
 220  */
 221 struct scatterlist *rds_message_alloc_sgs(struct rds_message *rm, int nents)
 222 {
 223         struct scatterlist *sg_first = (struct scatterlist *) &rm[1];
 224         struct scatterlist *sg_ret;
 225
 226         WARN_ON(rm->m_used_sgs + nents > rm->m_total_sgs);
 227         WARN_ON(!nents);
 228
 229         if (rm->m_used_sgs + nents > rm->m_total_sgs)
 230                 return NULL;
 231
 232         sg_ret = &sg_first[rm->m_used_sgs];
 233         sg_init_table(sg_ret, nents);
 234         rm->m_used_sgs += nents;
 235
 236         return sg_ret;
 237 }
 238
 239 struct rds_message *rds_message_map_pages(unsigned long *page_addrs, unsigned int total_len)
 240 {
 241         struct rds_message *rm;
 242         unsigned int i;
 243         int num_sgs = ceil(total_len, PAGE_SIZE);
 244         int extra_bytes = num_sgs * sizeof(struct scatterlist);
 245
 246         rm = rds_message_alloc(extra_bytes, GFP_NOWAIT);
 247         if (!rm)
 248                 return ERR_PTR(-ENOMEM);
 249
 250         set_bit(RDS_MSG_PAGEVEC, &rm->m_flags);
 251         rm->m_inc.i_hdr.h_len = cpu_to_be32(total_len);
 252         rm->data.op_nents = ceil(total_len, PAGE_SIZE);
 253         rm->data.op_sg = rds_message_alloc_sgs(rm, num_sgs);
 254         if (!rm->data.op_sg) {
 255                 rds_message_put(rm);
 256                 return ERR_PTR(-ENOMEM);
 257         }
 258
 259         for (i = 0; i < rm->data.op_nents; ++i) {
 260                 sg_set_page(&rm->data.op_sg[i],
 261                                 virt_to_page(page_addrs[i]),
 262                                 PAGE_SIZE, 0);
 263         }
 264
 265         return rm;
 266 }
 267
 268 int rds_message_copy_from_user(struct rds_message *rm, struct iov_iter *from)
 269 {
 270         unsigned long to_copy, nbytes;
 271         unsigned long sg_off;
 272         struct scatterlist *sg;
 273         int ret = 0;
 274
 275         rm->m_inc.i_hdr.h_len = cpu_to_be32(iov_iter_count(from));
 276
 277         /*
 278          * now allocate and copy in the data payload.
 279          */
 280         sg = rm->data.op_sg;
 281         sg_off = 0; /* Dear gcc, sg->page will be null from kzalloc. */
 282
 283         while (iov_iter_count(from)) {
 284                 if (!sg_page(sg)) {
 285                         ret = rds_page_remainder_alloc(sg, iov_iter_count(from),
 286                                                        GFP_HIGHUSER);
 287                         if (ret)
 288                                 return ret;
 289                         rm->data.op_nents++;
 290                         sg_off = 0;
 291                 }
 292
 293                 to_copy = min_t(unsigned long, iov_iter_count(from),
 294                                 sg->length - sg_off);
 295
 296                 rds_stats_add(s_copy_from_user, to_copy);
 297                 nbytes = copy_page_from_iter(sg_page(sg), sg->offset + sg_off,
 298                                              to_copy, from);
 299                 if (nbytes != to_copy)
 300                         return -EFAULT;
 301
 302                 sg_off += to_copy;
 303
 304                 if (sg_off == sg->length)
 305                         sg++;
 306         }
 307
 308         return ret;
 309 }
 310
 311 int rds_message_inc_copy_to_user(struct rds_incoming *inc, struct iov_iter *to)
 312 {
 313         struct rds_message *rm;
 314         struct scatterlist *sg;
 315         unsigned long to_copy;
 316         unsigned long vec_off;
 317         int copied;
 318         int ret;
 319         u32 len;
 320
 321         rm = container_of(inc, struct rds_message, m_inc);
 322         len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
 323
 324         sg = rm->data.op_sg;
 325         vec_off = 0;
 326         copied = 0;
 327
 328         while (iov_iter_count(to) && copied < len) {
 329                 to_copy = min_t(unsigned long, iov_iter_count(to),
 330                                 sg->length - vec_off);
 331                 to_copy = min_t(unsigned long, to_copy, len - copied);
 332
 333                 rds_stats_add(s_copy_to_user, to_copy);
 334                 ret = copy_page_to_iter(sg_page(sg), sg->offset + vec_off,
 335                                         to_copy, to);
 336                 if (ret != to_copy)
 337                         return -EFAULT;
 338
 339                 vec_off += to_copy;
 340                 copied += to_copy;
 341
 342                 if (vec_off == sg->length) {
 343                         vec_off = 0;
 344                         sg++;
 345                 }
 346         }
 347
 348         return copied;
 349 }
 350
 351 /*
 352  * If the message is still on the send queue, wait until the transport
 353  * is done with it. This is particularly important for RDMA operations.
 354  */
 355 void rds_message_wait(struct rds_message *rm)
 356 {
 357         wait_event_interruptible(rm->m_flush_wait,
 358                         !test_bit(RDS_MSG_MAPPED, &rm->m_flags));
 359 }
 360
 361 void rds_message_unmapped(struct rds_message *rm)
 362 {
 363         clear_bit(RDS_MSG_MAPPED, &rm->m_flags);
 364         wake_up_interruptible(&rm->m_flush_wait);
 365 }
 366 EXPORT_SYMBOL_GPL(rds_message_unmapped);
 367