linux/net/rds/rdma.c
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   1/*
   2 * Copyright (c) 2007, 2020 Oracle and/or its affiliates.
   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/pagemap.h>
  34#include <linux/slab.h>
  35#include <linux/rbtree.h>
  36#include <linux/dma-mapping.h> /* for DMA_*_DEVICE */
  37
  38#include "rds.h"
  39
  40/*
  41 * XXX
  42 *  - build with sparse
  43 *  - should we detect duplicate keys on a socket?  hmm.
  44 *  - an rdma is an mlock, apply rlimit?
  45 */
  46
  47/*
  48 * get the number of pages by looking at the page indices that the start and
  49 * end addresses fall in.
  50 *
  51 * Returns 0 if the vec is invalid.  It is invalid if the number of bytes
  52 * causes the address to wrap or overflows an unsigned int.  This comes
  53 * from being stored in the 'length' member of 'struct scatterlist'.
  54 */
  55static unsigned int rds_pages_in_vec(struct rds_iovec *vec)
  56{
  57        if ((vec->addr + vec->bytes <= vec->addr) ||
  58            (vec->bytes > (u64)UINT_MAX))
  59                return 0;
  60
  61        return ((vec->addr + vec->bytes + PAGE_SIZE - 1) >> PAGE_SHIFT) -
  62                (vec->addr >> PAGE_SHIFT);
  63}
  64
  65static struct rds_mr *rds_mr_tree_walk(struct rb_root *root, u64 key,
  66                                       struct rds_mr *insert)
  67{
  68        struct rb_node **p = &root->rb_node;
  69        struct rb_node *parent = NULL;
  70        struct rds_mr *mr;
  71
  72        while (*p) {
  73                parent = *p;
  74                mr = rb_entry(parent, struct rds_mr, r_rb_node);
  75
  76                if (key < mr->r_key)
  77                        p = &(*p)->rb_left;
  78                else if (key > mr->r_key)
  79                        p = &(*p)->rb_right;
  80                else
  81                        return mr;
  82        }
  83
  84        if (insert) {
  85                rb_link_node(&insert->r_rb_node, parent, p);
  86                rb_insert_color(&insert->r_rb_node, root);
  87                kref_get(&insert->r_kref);
  88        }
  89        return NULL;
  90}
  91
  92/*
  93 * Destroy the transport-specific part of a MR.
  94 */
  95static void rds_destroy_mr(struct rds_mr *mr)
  96{
  97        struct rds_sock *rs = mr->r_sock;
  98        void *trans_private = NULL;
  99        unsigned long flags;
 100
 101        rdsdebug("RDS: destroy mr key is %x refcnt %u\n",
 102                 mr->r_key, kref_read(&mr->r_kref));
 103
 104        spin_lock_irqsave(&rs->rs_rdma_lock, flags);
 105        if (!RB_EMPTY_NODE(&mr->r_rb_node))
 106                rb_erase(&mr->r_rb_node, &rs->rs_rdma_keys);
 107        trans_private = mr->r_trans_private;
 108        mr->r_trans_private = NULL;
 109        spin_unlock_irqrestore(&rs->rs_rdma_lock, flags);
 110
 111        if (trans_private)
 112                mr->r_trans->free_mr(trans_private, mr->r_invalidate);
 113}
 114
 115void __rds_put_mr_final(struct kref *kref)
 116{
 117        struct rds_mr *mr = container_of(kref, struct rds_mr, r_kref);
 118
 119        rds_destroy_mr(mr);
 120        kfree(mr);
 121}
 122
 123/*
 124 * By the time this is called we can't have any more ioctls called on
 125 * the socket so we don't need to worry about racing with others.
 126 */
 127void rds_rdma_drop_keys(struct rds_sock *rs)
 128{
 129        struct rds_mr *mr;
 130        struct rb_node *node;
 131        unsigned long flags;
 132
 133        /* Release any MRs associated with this socket */
 134        spin_lock_irqsave(&rs->rs_rdma_lock, flags);
 135        while ((node = rb_first(&rs->rs_rdma_keys))) {
 136                mr = rb_entry(node, struct rds_mr, r_rb_node);
 137                if (mr->r_trans == rs->rs_transport)
 138                        mr->r_invalidate = 0;
 139                rb_erase(&mr->r_rb_node, &rs->rs_rdma_keys);
 140                RB_CLEAR_NODE(&mr->r_rb_node);
 141                spin_unlock_irqrestore(&rs->rs_rdma_lock, flags);
 142                kref_put(&mr->r_kref, __rds_put_mr_final);
 143                spin_lock_irqsave(&rs->rs_rdma_lock, flags);
 144        }
 145        spin_unlock_irqrestore(&rs->rs_rdma_lock, flags);
 146
 147        if (rs->rs_transport && rs->rs_transport->flush_mrs)
 148                rs->rs_transport->flush_mrs();
 149}
 150
 151/*
 152 * Helper function to pin user pages.
 153 */
 154static int rds_pin_pages(unsigned long user_addr, unsigned int nr_pages,
 155                        struct page **pages, int write)
 156{
 157        unsigned int gup_flags = FOLL_LONGTERM;
 158        int ret;
 159
 160        if (write)
 161                gup_flags |= FOLL_WRITE;
 162
 163        ret = pin_user_pages_fast(user_addr, nr_pages, gup_flags, pages);
 164        if (ret >= 0 && ret < nr_pages) {
 165                unpin_user_pages(pages, ret);
 166                ret = -EFAULT;
 167        }
 168
 169        return ret;
 170}
 171
 172static int __rds_rdma_map(struct rds_sock *rs, struct rds_get_mr_args *args,
 173                          u64 *cookie_ret, struct rds_mr **mr_ret,
 174                          struct rds_conn_path *cp)
 175{
 176        struct rds_mr *mr = NULL, *found;
 177        struct scatterlist *sg = NULL;
 178        unsigned int nr_pages;
 179        struct page **pages = NULL;
 180        void *trans_private;
 181        unsigned long flags;
 182        rds_rdma_cookie_t cookie;
 183        unsigned int nents = 0;
 184        int need_odp = 0;
 185        long i;
 186        int ret;
 187
 188        if (ipv6_addr_any(&rs->rs_bound_addr) || !rs->rs_transport) {
 189                ret = -ENOTCONN; /* XXX not a great errno */
 190                goto out;
 191        }
 192
 193        if (!rs->rs_transport->get_mr) {
 194                ret = -EOPNOTSUPP;
 195                goto out;
 196        }
 197
 198        /* If the combination of the addr and size requested for this memory
 199         * region causes an integer overflow, return error.
 200         */
 201        if (((args->vec.addr + args->vec.bytes) < args->vec.addr) ||
 202            PAGE_ALIGN(args->vec.addr + args->vec.bytes) <
 203                    (args->vec.addr + args->vec.bytes)) {
 204                ret = -EINVAL;
 205                goto out;
 206        }
 207
 208        if (!can_do_mlock()) {
 209                ret = -EPERM;
 210                goto out;
 211        }
 212
 213        nr_pages = rds_pages_in_vec(&args->vec);
 214        if (nr_pages == 0) {
 215                ret = -EINVAL;
 216                goto out;
 217        }
 218
 219        /* Restrict the size of mr irrespective of underlying transport
 220         * To account for unaligned mr regions, subtract one from nr_pages
 221         */
 222        if ((nr_pages - 1) > (RDS_MAX_MSG_SIZE >> PAGE_SHIFT)) {
 223                ret = -EMSGSIZE;
 224                goto out;
 225        }
 226
 227        rdsdebug("RDS: get_mr addr %llx len %llu nr_pages %u\n",
 228                args->vec.addr, args->vec.bytes, nr_pages);
 229
 230        /* XXX clamp nr_pages to limit the size of this alloc? */
 231        pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
 232        if (!pages) {
 233                ret = -ENOMEM;
 234                goto out;
 235        }
 236
 237        mr = kzalloc(sizeof(struct rds_mr), GFP_KERNEL);
 238        if (!mr) {
 239                ret = -ENOMEM;
 240                goto out;
 241        }
 242
 243        kref_init(&mr->r_kref);
 244        RB_CLEAR_NODE(&mr->r_rb_node);
 245        mr->r_trans = rs->rs_transport;
 246        mr->r_sock = rs;
 247
 248        if (args->flags & RDS_RDMA_USE_ONCE)
 249                mr->r_use_once = 1;
 250        if (args->flags & RDS_RDMA_INVALIDATE)
 251                mr->r_invalidate = 1;
 252        if (args->flags & RDS_RDMA_READWRITE)
 253                mr->r_write = 1;
 254
 255        /*
 256         * Pin the pages that make up the user buffer and transfer the page
 257         * pointers to the mr's sg array.  We check to see if we've mapped
 258         * the whole region after transferring the partial page references
 259         * to the sg array so that we can have one page ref cleanup path.
 260         *
 261         * For now we have no flag that tells us whether the mapping is
 262         * r/o or r/w. We need to assume r/w, or we'll do a lot of RDMA to
 263         * the zero page.
 264         */
 265        ret = rds_pin_pages(args->vec.addr, nr_pages, pages, 1);
 266        if (ret == -EOPNOTSUPP) {
 267                need_odp = 1;
 268        } else if (ret <= 0) {
 269                goto out;
 270        } else {
 271                nents = ret;
 272                sg = kmalloc_array(nents, sizeof(*sg), GFP_KERNEL);
 273                if (!sg) {
 274                        ret = -ENOMEM;
 275                        goto out;
 276                }
 277                WARN_ON(!nents);
 278                sg_init_table(sg, nents);
 279
 280                /* Stick all pages into the scatterlist */
 281                for (i = 0 ; i < nents; i++)
 282                        sg_set_page(&sg[i], pages[i], PAGE_SIZE, 0);
 283
 284                rdsdebug("RDS: trans_private nents is %u\n", nents);
 285        }
 286        /* Obtain a transport specific MR. If this succeeds, the
 287         * s/g list is now owned by the MR.
 288         * Note that dma_map() implies that pending writes are
 289         * flushed to RAM, so no dma_sync is needed here. */
 290        trans_private = rs->rs_transport->get_mr(
 291                sg, nents, rs, &mr->r_key, cp ? cp->cp_conn : NULL,
 292                args->vec.addr, args->vec.bytes,
 293                need_odp ? ODP_ZEROBASED : ODP_NOT_NEEDED);
 294
 295        if (IS_ERR(trans_private)) {
 296                /* In ODP case, we don't GUP pages, so don't need
 297                 * to release anything.
 298                 */
 299                if (!need_odp) {
 300                        unpin_user_pages(pages, nr_pages);
 301                        kfree(sg);
 302                }
 303                ret = PTR_ERR(trans_private);
 304                goto out;
 305        }
 306
 307        mr->r_trans_private = trans_private;
 308
 309        rdsdebug("RDS: get_mr put_user key is %x cookie_addr %p\n",
 310               mr->r_key, (void *)(unsigned long) args->cookie_addr);
 311
 312        /* The user may pass us an unaligned address, but we can only
 313         * map page aligned regions. So we keep the offset, and build
 314         * a 64bit cookie containing <R_Key, offset> and pass that
 315         * around. */
 316        if (need_odp)
 317                cookie = rds_rdma_make_cookie(mr->r_key, 0);
 318        else
 319                cookie = rds_rdma_make_cookie(mr->r_key,
 320                                              args->vec.addr & ~PAGE_MASK);
 321        if (cookie_ret)
 322                *cookie_ret = cookie;
 323
 324        if (args->cookie_addr &&
 325            put_user(cookie, (u64 __user *)(unsigned long)args->cookie_addr)) {
 326                if (!need_odp) {
 327                        unpin_user_pages(pages, nr_pages);
 328                        kfree(sg);
 329                }
 330                ret = -EFAULT;
 331                goto out;
 332        }
 333
 334        /* Inserting the new MR into the rbtree bumps its
 335         * reference count. */
 336        spin_lock_irqsave(&rs->rs_rdma_lock, flags);
 337        found = rds_mr_tree_walk(&rs->rs_rdma_keys, mr->r_key, mr);
 338        spin_unlock_irqrestore(&rs->rs_rdma_lock, flags);
 339
 340        BUG_ON(found && found != mr);
 341
 342        rdsdebug("RDS: get_mr key is %x\n", mr->r_key);
 343        if (mr_ret) {
 344                kref_get(&mr->r_kref);
 345                *mr_ret = mr;
 346        }
 347
 348        ret = 0;
 349out:
 350        kfree(pages);
 351        if (mr)
 352                kref_put(&mr->r_kref, __rds_put_mr_final);
 353        return ret;
 354}
 355
 356int rds_get_mr(struct rds_sock *rs, sockptr_t optval, int optlen)
 357{
 358        struct rds_get_mr_args args;
 359
 360        if (optlen != sizeof(struct rds_get_mr_args))
 361                return -EINVAL;
 362
 363        if (copy_from_sockptr(&args, optval, sizeof(struct rds_get_mr_args)))
 364                return -EFAULT;
 365
 366        return __rds_rdma_map(rs, &args, NULL, NULL, NULL);
 367}
 368
 369int rds_get_mr_for_dest(struct rds_sock *rs, sockptr_t optval, int optlen)
 370{
 371        struct rds_get_mr_for_dest_args args;
 372        struct rds_get_mr_args new_args;
 373
 374        if (optlen != sizeof(struct rds_get_mr_for_dest_args))
 375                return -EINVAL;
 376
 377        if (copy_from_sockptr(&args, optval,
 378                           sizeof(struct rds_get_mr_for_dest_args)))
 379                return -EFAULT;
 380
 381        /*
 382         * Initially, just behave like get_mr().
 383         * TODO: Implement get_mr as wrapper around this
 384         *       and deprecate it.
 385         */
 386        new_args.vec = args.vec;
 387        new_args.cookie_addr = args.cookie_addr;
 388        new_args.flags = args.flags;
 389
 390        return __rds_rdma_map(rs, &new_args, NULL, NULL, NULL);
 391}
 392
 393/*
 394 * Free the MR indicated by the given R_Key
 395 */
 396int rds_free_mr(struct rds_sock *rs, sockptr_t optval, int optlen)
 397{
 398        struct rds_free_mr_args args;
 399        struct rds_mr *mr;
 400        unsigned long flags;
 401
 402        if (optlen != sizeof(struct rds_free_mr_args))
 403                return -EINVAL;
 404
 405        if (copy_from_sockptr(&args, optval, sizeof(struct rds_free_mr_args)))
 406                return -EFAULT;
 407
 408        /* Special case - a null cookie means flush all unused MRs */
 409        if (args.cookie == 0) {
 410                if (!rs->rs_transport || !rs->rs_transport->flush_mrs)
 411                        return -EINVAL;
 412                rs->rs_transport->flush_mrs();
 413                return 0;
 414        }
 415
 416        /* Look up the MR given its R_key and remove it from the rbtree
 417         * so nobody else finds it.
 418         * This should also prevent races with rds_rdma_unuse.
 419         */
 420        spin_lock_irqsave(&rs->rs_rdma_lock, flags);
 421        mr = rds_mr_tree_walk(&rs->rs_rdma_keys, rds_rdma_cookie_key(args.cookie), NULL);
 422        if (mr) {
 423                rb_erase(&mr->r_rb_node, &rs->rs_rdma_keys);
 424                RB_CLEAR_NODE(&mr->r_rb_node);
 425                if (args.flags & RDS_RDMA_INVALIDATE)
 426                        mr->r_invalidate = 1;
 427        }
 428        spin_unlock_irqrestore(&rs->rs_rdma_lock, flags);
 429
 430        if (!mr)
 431                return -EINVAL;
 432
 433        kref_put(&mr->r_kref, __rds_put_mr_final);
 434        return 0;
 435}
 436
 437/*
 438 * This is called when we receive an extension header that
 439 * tells us this MR was used. It allows us to implement
 440 * use_once semantics
 441 */
 442void rds_rdma_unuse(struct rds_sock *rs, u32 r_key, int force)
 443{
 444        struct rds_mr *mr;
 445        unsigned long flags;
 446        int zot_me = 0;
 447
 448        spin_lock_irqsave(&rs->rs_rdma_lock, flags);
 449        mr = rds_mr_tree_walk(&rs->rs_rdma_keys, r_key, NULL);
 450        if (!mr) {
 451                pr_debug("rds: trying to unuse MR with unknown r_key %u!\n",
 452                         r_key);
 453                spin_unlock_irqrestore(&rs->rs_rdma_lock, flags);
 454                return;
 455        }
 456
 457        /* Get a reference so that the MR won't go away before calling
 458         * sync_mr() below.
 459         */
 460        kref_get(&mr->r_kref);
 461
 462        /* If it is going to be freed, remove it from the tree now so
 463         * that no other thread can find it and free it.
 464         */
 465        if (mr->r_use_once || force) {
 466                rb_erase(&mr->r_rb_node, &rs->rs_rdma_keys);
 467                RB_CLEAR_NODE(&mr->r_rb_node);
 468                zot_me = 1;
 469        }
 470        spin_unlock_irqrestore(&rs->rs_rdma_lock, flags);
 471
 472        /* May have to issue a dma_sync on this memory region.
 473         * Note we could avoid this if the operation was a RDMA READ,
 474         * but at this point we can't tell. */
 475        if (mr->r_trans->sync_mr)
 476                mr->r_trans->sync_mr(mr->r_trans_private, DMA_FROM_DEVICE);
 477
 478        /* Release the reference held above. */
 479        kref_put(&mr->r_kref, __rds_put_mr_final);
 480
 481        /* If the MR was marked as invalidate, this will
 482         * trigger an async flush. */
 483        if (zot_me)
 484                kref_put(&mr->r_kref, __rds_put_mr_final);
 485}
 486
 487void rds_rdma_free_op(struct rm_rdma_op *ro)
 488{
 489        unsigned int i;
 490
 491        if (ro->op_odp_mr) {
 492                kref_put(&ro->op_odp_mr->r_kref, __rds_put_mr_final);
 493        } else {
 494                for (i = 0; i < ro->op_nents; i++) {
 495                        struct page *page = sg_page(&ro->op_sg[i]);
 496
 497                        /* Mark page dirty if it was possibly modified, which
 498                         * is the case for a RDMA_READ which copies from remote
 499                         * to local memory
 500                         */
 501                        unpin_user_pages_dirty_lock(&page, 1, !ro->op_write);
 502                }
 503        }
 504
 505        kfree(ro->op_notifier);
 506        ro->op_notifier = NULL;
 507        ro->op_active = 0;
 508        ro->op_odp_mr = NULL;
 509}
 510
 511void rds_atomic_free_op(struct rm_atomic_op *ao)
 512{
 513        struct page *page = sg_page(ao->op_sg);
 514
 515        /* Mark page dirty if it was possibly modified, which
 516         * is the case for a RDMA_READ which copies from remote
 517         * to local memory */
 518        unpin_user_pages_dirty_lock(&page, 1, true);
 519
 520        kfree(ao->op_notifier);
 521        ao->op_notifier = NULL;
 522        ao->op_active = 0;
 523}
 524
 525
 526/*
 527 * Count the number of pages needed to describe an incoming iovec array.
 528 */
 529static int rds_rdma_pages(struct rds_iovec iov[], int nr_iovecs)
 530{
 531        int tot_pages = 0;
 532        unsigned int nr_pages;
 533        unsigned int i;
 534
 535        /* figure out the number of pages in the vector */
 536        for (i = 0; i < nr_iovecs; i++) {
 537                nr_pages = rds_pages_in_vec(&iov[i]);
 538                if (nr_pages == 0)
 539                        return -EINVAL;
 540
 541                tot_pages += nr_pages;
 542
 543                /*
 544                 * nr_pages for one entry is limited to (UINT_MAX>>PAGE_SHIFT)+1,
 545                 * so tot_pages cannot overflow without first going negative.
 546                 */
 547                if (tot_pages < 0)
 548                        return -EINVAL;
 549        }
 550
 551        return tot_pages;
 552}
 553
 554int rds_rdma_extra_size(struct rds_rdma_args *args,
 555                        struct rds_iov_vector *iov)
 556{
 557        struct rds_iovec *vec;
 558        struct rds_iovec __user *local_vec;
 559        int tot_pages = 0;
 560        unsigned int nr_pages;
 561        unsigned int i;
 562
 563        local_vec = (struct rds_iovec __user *)(unsigned long) args->local_vec_addr;
 564
 565        if (args->nr_local == 0)
 566                return -EINVAL;
 567
 568        iov->iov = kcalloc(args->nr_local,
 569                           sizeof(struct rds_iovec),
 570                           GFP_KERNEL);
 571        if (!iov->iov)
 572                return -ENOMEM;
 573
 574        vec = &iov->iov[0];
 575
 576        if (copy_from_user(vec, local_vec, args->nr_local *
 577                           sizeof(struct rds_iovec)))
 578                return -EFAULT;
 579        iov->len = args->nr_local;
 580
 581        /* figure out the number of pages in the vector */
 582        for (i = 0; i < args->nr_local; i++, vec++) {
 583
 584                nr_pages = rds_pages_in_vec(vec);
 585                if (nr_pages == 0)
 586                        return -EINVAL;
 587
 588                tot_pages += nr_pages;
 589
 590                /*
 591                 * nr_pages for one entry is limited to (UINT_MAX>>PAGE_SHIFT)+1,
 592                 * so tot_pages cannot overflow without first going negative.
 593                 */
 594                if (tot_pages < 0)
 595                        return -EINVAL;
 596        }
 597
 598        return tot_pages * sizeof(struct scatterlist);
 599}
 600
 601/*
 602 * The application asks for a RDMA transfer.
 603 * Extract all arguments and set up the rdma_op
 604 */
 605int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,
 606                       struct cmsghdr *cmsg,
 607                       struct rds_iov_vector *vec)
 608{
 609        struct rds_rdma_args *args;
 610        struct rm_rdma_op *op = &rm->rdma;
 611        int nr_pages;
 612        unsigned int nr_bytes;
 613        struct page **pages = NULL;
 614        struct rds_iovec *iovs;
 615        unsigned int i, j;
 616        int ret = 0;
 617        bool odp_supported = true;
 618
 619        if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct rds_rdma_args))
 620            || rm->rdma.op_active)
 621                return -EINVAL;
 622
 623        args = CMSG_DATA(cmsg);
 624
 625        if (ipv6_addr_any(&rs->rs_bound_addr)) {
 626                ret = -ENOTCONN; /* XXX not a great errno */
 627                goto out_ret;
 628        }
 629
 630        if (args->nr_local > UIO_MAXIOV) {
 631                ret = -EMSGSIZE;
 632                goto out_ret;
 633        }
 634
 635        if (vec->len != args->nr_local) {
 636                ret = -EINVAL;
 637                goto out_ret;
 638        }
 639        /* odp-mr is not supported for multiple requests within one message */
 640        if (args->nr_local != 1)
 641                odp_supported = false;
 642
 643        iovs = vec->iov;
 644
 645        nr_pages = rds_rdma_pages(iovs, args->nr_local);
 646        if (nr_pages < 0) {
 647                ret = -EINVAL;
 648                goto out_ret;
 649        }
 650
 651        pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
 652        if (!pages) {
 653                ret = -ENOMEM;
 654                goto out_ret;
 655        }
 656
 657        op->op_write = !!(args->flags & RDS_RDMA_READWRITE);
 658        op->op_fence = !!(args->flags & RDS_RDMA_FENCE);
 659        op->op_notify = !!(args->flags & RDS_RDMA_NOTIFY_ME);
 660        op->op_silent = !!(args->flags & RDS_RDMA_SILENT);
 661        op->op_active = 1;
 662        op->op_recverr = rs->rs_recverr;
 663        op->op_odp_mr = NULL;
 664
 665        WARN_ON(!nr_pages);
 666        op->op_sg = rds_message_alloc_sgs(rm, nr_pages);
 667        if (IS_ERR(op->op_sg)) {
 668                ret = PTR_ERR(op->op_sg);
 669                goto out_pages;
 670        }
 671
 672        if (op->op_notify || op->op_recverr) {
 673                /* We allocate an uninitialized notifier here, because
 674                 * we don't want to do that in the completion handler. We
 675                 * would have to use GFP_ATOMIC there, and don't want to deal
 676                 * with failed allocations.
 677                 */
 678                op->op_notifier = kmalloc(sizeof(struct rds_notifier), GFP_KERNEL);
 679                if (!op->op_notifier) {
 680                        ret = -ENOMEM;
 681                        goto out_pages;
 682                }
 683                op->op_notifier->n_user_token = args->user_token;
 684                op->op_notifier->n_status = RDS_RDMA_SUCCESS;
 685        }
 686
 687        /* The cookie contains the R_Key of the remote memory region, and
 688         * optionally an offset into it. This is how we implement RDMA into
 689         * unaligned memory.
 690         * When setting up the RDMA, we need to add that offset to the
 691         * destination address (which is really an offset into the MR)
 692         * FIXME: We may want to move this into ib_rdma.c
 693         */
 694        op->op_rkey = rds_rdma_cookie_key(args->cookie);
 695        op->op_remote_addr = args->remote_vec.addr + rds_rdma_cookie_offset(args->cookie);
 696
 697        nr_bytes = 0;
 698
 699        rdsdebug("RDS: rdma prepare nr_local %llu rva %llx rkey %x\n",
 700               (unsigned long long)args->nr_local,
 701               (unsigned long long)args->remote_vec.addr,
 702               op->op_rkey);
 703
 704        for (i = 0; i < args->nr_local; i++) {
 705                struct rds_iovec *iov = &iovs[i];
 706                /* don't need to check, rds_rdma_pages() verified nr will be +nonzero */
 707                unsigned int nr = rds_pages_in_vec(iov);
 708
 709                rs->rs_user_addr = iov->addr;
 710                rs->rs_user_bytes = iov->bytes;
 711
 712                /* If it's a WRITE operation, we want to pin the pages for reading.
 713                 * If it's a READ operation, we need to pin the pages for writing.
 714                 */
 715                ret = rds_pin_pages(iov->addr, nr, pages, !op->op_write);
 716                if ((!odp_supported && ret <= 0) ||
 717                    (odp_supported && ret <= 0 && ret != -EOPNOTSUPP))
 718                        goto out_pages;
 719
 720                if (ret == -EOPNOTSUPP) {
 721                        struct rds_mr *local_odp_mr;
 722
 723                        if (!rs->rs_transport->get_mr) {
 724                                ret = -EOPNOTSUPP;
 725                                goto out_pages;
 726                        }
 727                        local_odp_mr =
 728                                kzalloc(sizeof(*local_odp_mr), GFP_KERNEL);
 729                        if (!local_odp_mr) {
 730                                ret = -ENOMEM;
 731                                goto out_pages;
 732                        }
 733                        RB_CLEAR_NODE(&local_odp_mr->r_rb_node);
 734                        kref_init(&local_odp_mr->r_kref);
 735                        local_odp_mr->r_trans = rs->rs_transport;
 736                        local_odp_mr->r_sock = rs;
 737                        local_odp_mr->r_trans_private =
 738                                rs->rs_transport->get_mr(
 739                                        NULL, 0, rs, &local_odp_mr->r_key, NULL,
 740                                        iov->addr, iov->bytes, ODP_VIRTUAL);
 741                        if (IS_ERR(local_odp_mr->r_trans_private)) {
 742                                ret = IS_ERR(local_odp_mr->r_trans_private);
 743                                rdsdebug("get_mr ret %d %p\"", ret,
 744                                         local_odp_mr->r_trans_private);
 745                                kfree(local_odp_mr);
 746                                ret = -EOPNOTSUPP;
 747                                goto out_pages;
 748                        }
 749                        rdsdebug("Need odp; local_odp_mr %p trans_private %p\n",
 750                                 local_odp_mr, local_odp_mr->r_trans_private);
 751                        op->op_odp_mr = local_odp_mr;
 752                        op->op_odp_addr = iov->addr;
 753                }
 754
 755                rdsdebug("RDS: nr_bytes %u nr %u iov->bytes %llu iov->addr %llx\n",
 756                         nr_bytes, nr, iov->bytes, iov->addr);
 757
 758                nr_bytes += iov->bytes;
 759
 760                for (j = 0; j < nr; j++) {
 761                        unsigned int offset = iov->addr & ~PAGE_MASK;
 762                        struct scatterlist *sg;
 763
 764                        sg = &op->op_sg[op->op_nents + j];
 765                        sg_set_page(sg, pages[j],
 766                                        min_t(unsigned int, iov->bytes, PAGE_SIZE - offset),
 767                                        offset);
 768
 769                        sg_dma_len(sg) = sg->length;
 770                        rdsdebug("RDS: sg->offset %x sg->len %x iov->addr %llx iov->bytes %llu\n",
 771                               sg->offset, sg->length, iov->addr, iov->bytes);
 772
 773                        iov->addr += sg->length;
 774                        iov->bytes -= sg->length;
 775                }
 776
 777                op->op_nents += nr;
 778        }
 779
 780        if (nr_bytes > args->remote_vec.bytes) {
 781                rdsdebug("RDS nr_bytes %u remote_bytes %u do not match\n",
 782                                nr_bytes,
 783                                (unsigned int) args->remote_vec.bytes);
 784                ret = -EINVAL;
 785                goto out_pages;
 786        }
 787        op->op_bytes = nr_bytes;
 788        ret = 0;
 789
 790out_pages:
 791        kfree(pages);
 792out_ret:
 793        if (ret)
 794                rds_rdma_free_op(op);
 795        else
 796                rds_stats_inc(s_send_rdma);
 797
 798        return ret;
 799}
 800
 801/*
 802 * The application wants us to pass an RDMA destination (aka MR)
 803 * to the remote
 804 */
 805int rds_cmsg_rdma_dest(struct rds_sock *rs, struct rds_message *rm,
 806                          struct cmsghdr *cmsg)
 807{
 808        unsigned long flags;
 809        struct rds_mr *mr;
 810        u32 r_key;
 811        int err = 0;
 812
 813        if (cmsg->cmsg_len < CMSG_LEN(sizeof(rds_rdma_cookie_t)) ||
 814            rm->m_rdma_cookie != 0)
 815                return -EINVAL;
 816
 817        memcpy(&rm->m_rdma_cookie, CMSG_DATA(cmsg), sizeof(rm->m_rdma_cookie));
 818
 819        /* We are reusing a previously mapped MR here. Most likely, the
 820         * application has written to the buffer, so we need to explicitly
 821         * flush those writes to RAM. Otherwise the HCA may not see them
 822         * when doing a DMA from that buffer.
 823         */
 824        r_key = rds_rdma_cookie_key(rm->m_rdma_cookie);
 825
 826        spin_lock_irqsave(&rs->rs_rdma_lock, flags);
 827        mr = rds_mr_tree_walk(&rs->rs_rdma_keys, r_key, NULL);
 828        if (!mr)
 829                err = -EINVAL;  /* invalid r_key */
 830        else
 831                kref_get(&mr->r_kref);
 832        spin_unlock_irqrestore(&rs->rs_rdma_lock, flags);
 833
 834        if (mr) {
 835                mr->r_trans->sync_mr(mr->r_trans_private,
 836                                     DMA_TO_DEVICE);
 837                rm->rdma.op_rdma_mr = mr;
 838        }
 839        return err;
 840}
 841
 842/*
 843 * The application passes us an address range it wants to enable RDMA
 844 * to/from. We map the area, and save the <R_Key,offset> pair
 845 * in rm->m_rdma_cookie. This causes it to be sent along to the peer
 846 * in an extension header.
 847 */
 848int rds_cmsg_rdma_map(struct rds_sock *rs, struct rds_message *rm,
 849                          struct cmsghdr *cmsg)
 850{
 851        if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct rds_get_mr_args)) ||
 852            rm->m_rdma_cookie != 0)
 853                return -EINVAL;
 854
 855        return __rds_rdma_map(rs, CMSG_DATA(cmsg), &rm->m_rdma_cookie,
 856                              &rm->rdma.op_rdma_mr, rm->m_conn_path);
 857}
 858
 859/*
 860 * Fill in rds_message for an atomic request.
 861 */
 862int rds_cmsg_atomic(struct rds_sock *rs, struct rds_message *rm,
 863                    struct cmsghdr *cmsg)
 864{
 865        struct page *page = NULL;
 866        struct rds_atomic_args *args;
 867        int ret = 0;
 868
 869        if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct rds_atomic_args))
 870         || rm->atomic.op_active)
 871                return -EINVAL;
 872
 873        args = CMSG_DATA(cmsg);
 874
 875        /* Nonmasked & masked cmsg ops converted to masked hw ops */
 876        switch (cmsg->cmsg_type) {
 877        case RDS_CMSG_ATOMIC_FADD:
 878                rm->atomic.op_type = RDS_ATOMIC_TYPE_FADD;
 879                rm->atomic.op_m_fadd.add = args->fadd.add;
 880                rm->atomic.op_m_fadd.nocarry_mask = 0;
 881                break;
 882        case RDS_CMSG_MASKED_ATOMIC_FADD:
 883                rm->atomic.op_type = RDS_ATOMIC_TYPE_FADD;
 884                rm->atomic.op_m_fadd.add = args->m_fadd.add;
 885                rm->atomic.op_m_fadd.nocarry_mask = args->m_fadd.nocarry_mask;
 886                break;
 887        case RDS_CMSG_ATOMIC_CSWP:
 888                rm->atomic.op_type = RDS_ATOMIC_TYPE_CSWP;
 889                rm->atomic.op_m_cswp.compare = args->cswp.compare;
 890                rm->atomic.op_m_cswp.swap = args->cswp.swap;
 891                rm->atomic.op_m_cswp.compare_mask = ~0;
 892                rm->atomic.op_m_cswp.swap_mask = ~0;
 893                break;
 894        case RDS_CMSG_MASKED_ATOMIC_CSWP:
 895                rm->atomic.op_type = RDS_ATOMIC_TYPE_CSWP;
 896                rm->atomic.op_m_cswp.compare = args->m_cswp.compare;
 897                rm->atomic.op_m_cswp.swap = args->m_cswp.swap;
 898                rm->atomic.op_m_cswp.compare_mask = args->m_cswp.compare_mask;
 899                rm->atomic.op_m_cswp.swap_mask = args->m_cswp.swap_mask;
 900                break;
 901        default:
 902                BUG(); /* should never happen */
 903        }
 904
 905        rm->atomic.op_notify = !!(args->flags & RDS_RDMA_NOTIFY_ME);
 906        rm->atomic.op_silent = !!(args->flags & RDS_RDMA_SILENT);
 907        rm->atomic.op_active = 1;
 908        rm->atomic.op_recverr = rs->rs_recverr;
 909        rm->atomic.op_sg = rds_message_alloc_sgs(rm, 1);
 910        if (IS_ERR(rm->atomic.op_sg)) {
 911                ret = PTR_ERR(rm->atomic.op_sg);
 912                goto err;
 913        }
 914
 915        /* verify 8 byte-aligned */
 916        if (args->local_addr & 0x7) {
 917                ret = -EFAULT;
 918                goto err;
 919        }
 920
 921        ret = rds_pin_pages(args->local_addr, 1, &page, 1);
 922        if (ret != 1)
 923                goto err;
 924        ret = 0;
 925
 926        sg_set_page(rm->atomic.op_sg, page, 8, offset_in_page(args->local_addr));
 927
 928        if (rm->atomic.op_notify || rm->atomic.op_recverr) {
 929                /* We allocate an uninitialized notifier here, because
 930                 * we don't want to do that in the completion handler. We
 931                 * would have to use GFP_ATOMIC there, and don't want to deal
 932                 * with failed allocations.
 933                 */
 934                rm->atomic.op_notifier = kmalloc(sizeof(*rm->atomic.op_notifier), GFP_KERNEL);
 935                if (!rm->atomic.op_notifier) {
 936                        ret = -ENOMEM;
 937                        goto err;
 938                }
 939
 940                rm->atomic.op_notifier->n_user_token = args->user_token;
 941                rm->atomic.op_notifier->n_status = RDS_RDMA_SUCCESS;
 942        }
 943
 944        rm->atomic.op_rkey = rds_rdma_cookie_key(args->cookie);
 945        rm->atomic.op_remote_addr = args->remote_addr + rds_rdma_cookie_offset(args->cookie);
 946
 947        return ret;
 948err:
 949        if (page)
 950                unpin_user_page(page);
 951        rm->atomic.op_active = 0;
 952        kfree(rm->atomic.op_notifier);
 953
 954        return ret;
 955}
 956