linux/fs/nfs/pagelist.c
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   1/*
   2 * linux/fs/nfs/pagelist.c
   3 *
   4 * A set of helper functions for managing NFS read and write requests.
   5 * The main purpose of these routines is to provide support for the
   6 * coalescing of several requests into a single RPC call.
   7 *
   8 * Copyright 2000, 2001 (c) Trond Myklebust <trond.myklebust@fys.uio.no>
   9 *
  10 */
  11
  12#include <linux/slab.h>
  13#include <linux/file.h>
  14#include <linux/sched.h>
  15#include <linux/sunrpc/clnt.h>
  16#include <linux/nfs.h>
  17#include <linux/nfs3.h>
  18#include <linux/nfs4.h>
  19#include <linux/nfs_page.h>
  20#include <linux/nfs_fs.h>
  21#include <linux/nfs_mount.h>
  22#include <linux/export.h>
  23
  24#include "internal.h"
  25#include "pnfs.h"
  26
  27#define NFSDBG_FACILITY         NFSDBG_PAGECACHE
  28
  29static struct kmem_cache *nfs_page_cachep;
  30static const struct rpc_call_ops nfs_pgio_common_ops;
  31
  32struct nfs_pgio_mirror *
  33nfs_pgio_current_mirror(struct nfs_pageio_descriptor *desc)
  34{
  35        return nfs_pgio_has_mirroring(desc) ?
  36                &desc->pg_mirrors[desc->pg_mirror_idx] :
  37                &desc->pg_mirrors[0];
  38}
  39EXPORT_SYMBOL_GPL(nfs_pgio_current_mirror);
  40
  41void nfs_pgheader_init(struct nfs_pageio_descriptor *desc,
  42                       struct nfs_pgio_header *hdr,
  43                       void (*release)(struct nfs_pgio_header *hdr))
  44{
  45        struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
  46
  47
  48        hdr->req = nfs_list_entry(mirror->pg_list.next);
  49        hdr->inode = desc->pg_inode;
  50        hdr->cred = hdr->req->wb_context->cred;
  51        hdr->io_start = req_offset(hdr->req);
  52        hdr->good_bytes = mirror->pg_count;
  53        hdr->io_completion = desc->pg_io_completion;
  54        hdr->dreq = desc->pg_dreq;
  55        hdr->release = release;
  56        hdr->completion_ops = desc->pg_completion_ops;
  57        if (hdr->completion_ops->init_hdr)
  58                hdr->completion_ops->init_hdr(hdr);
  59
  60        hdr->pgio_mirror_idx = desc->pg_mirror_idx;
  61}
  62EXPORT_SYMBOL_GPL(nfs_pgheader_init);
  63
  64void nfs_set_pgio_error(struct nfs_pgio_header *hdr, int error, loff_t pos)
  65{
  66        spin_lock(&hdr->lock);
  67        if (!test_and_set_bit(NFS_IOHDR_ERROR, &hdr->flags)
  68            || pos < hdr->io_start + hdr->good_bytes) {
  69                clear_bit(NFS_IOHDR_EOF, &hdr->flags);
  70                hdr->good_bytes = pos - hdr->io_start;
  71                hdr->error = error;
  72        }
  73        spin_unlock(&hdr->lock);
  74}
  75
  76static inline struct nfs_page *
  77nfs_page_alloc(void)
  78{
  79        struct nfs_page *p = kmem_cache_zalloc(nfs_page_cachep, GFP_NOIO);
  80        if (p)
  81                INIT_LIST_HEAD(&p->wb_list);
  82        return p;
  83}
  84
  85static inline void
  86nfs_page_free(struct nfs_page *p)
  87{
  88        kmem_cache_free(nfs_page_cachep, p);
  89}
  90
  91/**
  92 * nfs_iocounter_wait - wait for i/o to complete
  93 * @l_ctx: nfs_lock_context with io_counter to use
  94 *
  95 * returns -ERESTARTSYS if interrupted by a fatal signal.
  96 * Otherwise returns 0 once the io_count hits 0.
  97 */
  98int
  99nfs_iocounter_wait(struct nfs_lock_context *l_ctx)
 100{
 101        return wait_on_atomic_t(&l_ctx->io_count, nfs_wait_atomic_killable,
 102                        TASK_KILLABLE);
 103}
 104
 105/**
 106 * nfs_async_iocounter_wait - wait on a rpc_waitqueue for I/O
 107 * to complete
 108 * @task: the rpc_task that should wait
 109 * @l_ctx: nfs_lock_context with io_counter to check
 110 *
 111 * Returns true if there is outstanding I/O to wait on and the
 112 * task has been put to sleep.
 113 */
 114bool
 115nfs_async_iocounter_wait(struct rpc_task *task, struct nfs_lock_context *l_ctx)
 116{
 117        struct inode *inode = d_inode(l_ctx->open_context->dentry);
 118        bool ret = false;
 119
 120        if (atomic_read(&l_ctx->io_count) > 0) {
 121                rpc_sleep_on(&NFS_SERVER(inode)->uoc_rpcwaitq, task, NULL);
 122                ret = true;
 123        }
 124
 125        if (atomic_read(&l_ctx->io_count) == 0) {
 126                rpc_wake_up_queued_task(&NFS_SERVER(inode)->uoc_rpcwaitq, task);
 127                ret = false;
 128        }
 129
 130        return ret;
 131}
 132EXPORT_SYMBOL_GPL(nfs_async_iocounter_wait);
 133
 134/*
 135 * nfs_page_group_lock - lock the head of the page group
 136 * @req - request in group that is to be locked
 137 *
 138 * this lock must be held when traversing or modifying the page
 139 * group list
 140 *
 141 * return 0 on success, < 0 on error
 142 */
 143int
 144nfs_page_group_lock(struct nfs_page *req)
 145{
 146        struct nfs_page *head = req->wb_head;
 147
 148        WARN_ON_ONCE(head != head->wb_head);
 149
 150        if (!test_and_set_bit(PG_HEADLOCK, &head->wb_flags))
 151                return 0;
 152
 153        set_bit(PG_CONTENDED1, &head->wb_flags);
 154        smp_mb__after_atomic();
 155        return wait_on_bit_lock(&head->wb_flags, PG_HEADLOCK,
 156                                TASK_UNINTERRUPTIBLE);
 157}
 158
 159/*
 160 * nfs_page_group_unlock - unlock the head of the page group
 161 * @req - request in group that is to be unlocked
 162 */
 163void
 164nfs_page_group_unlock(struct nfs_page *req)
 165{
 166        struct nfs_page *head = req->wb_head;
 167
 168        WARN_ON_ONCE(head != head->wb_head);
 169
 170        smp_mb__before_atomic();
 171        clear_bit(PG_HEADLOCK, &head->wb_flags);
 172        smp_mb__after_atomic();
 173        if (!test_bit(PG_CONTENDED1, &head->wb_flags))
 174                return;
 175        wake_up_bit(&head->wb_flags, PG_HEADLOCK);
 176}
 177
 178/*
 179 * nfs_page_group_sync_on_bit_locked
 180 *
 181 * must be called with page group lock held
 182 */
 183static bool
 184nfs_page_group_sync_on_bit_locked(struct nfs_page *req, unsigned int bit)
 185{
 186        struct nfs_page *head = req->wb_head;
 187        struct nfs_page *tmp;
 188
 189        WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &head->wb_flags));
 190        WARN_ON_ONCE(test_and_set_bit(bit, &req->wb_flags));
 191
 192        tmp = req->wb_this_page;
 193        while (tmp != req) {
 194                if (!test_bit(bit, &tmp->wb_flags))
 195                        return false;
 196                tmp = tmp->wb_this_page;
 197        }
 198
 199        /* true! reset all bits */
 200        tmp = req;
 201        do {
 202                clear_bit(bit, &tmp->wb_flags);
 203                tmp = tmp->wb_this_page;
 204        } while (tmp != req);
 205
 206        return true;
 207}
 208
 209/*
 210 * nfs_page_group_sync_on_bit - set bit on current request, but only
 211 *   return true if the bit is set for all requests in page group
 212 * @req - request in page group
 213 * @bit - PG_* bit that is used to sync page group
 214 */
 215bool nfs_page_group_sync_on_bit(struct nfs_page *req, unsigned int bit)
 216{
 217        bool ret;
 218
 219        nfs_page_group_lock(req);
 220        ret = nfs_page_group_sync_on_bit_locked(req, bit);
 221        nfs_page_group_unlock(req);
 222
 223        return ret;
 224}
 225
 226/*
 227 * nfs_page_group_init - Initialize the page group linkage for @req
 228 * @req - a new nfs request
 229 * @prev - the previous request in page group, or NULL if @req is the first
 230 *         or only request in the group (the head).
 231 */
 232static inline void
 233nfs_page_group_init(struct nfs_page *req, struct nfs_page *prev)
 234{
 235        struct inode *inode;
 236        WARN_ON_ONCE(prev == req);
 237
 238        if (!prev) {
 239                /* a head request */
 240                req->wb_head = req;
 241                req->wb_this_page = req;
 242        } else {
 243                /* a subrequest */
 244                WARN_ON_ONCE(prev->wb_this_page != prev->wb_head);
 245                WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &prev->wb_head->wb_flags));
 246                req->wb_head = prev->wb_head;
 247                req->wb_this_page = prev->wb_this_page;
 248                prev->wb_this_page = req;
 249
 250                /* All subrequests take a ref on the head request until
 251                 * nfs_page_group_destroy is called */
 252                kref_get(&req->wb_head->wb_kref);
 253
 254                /* grab extra ref and bump the request count if head request
 255                 * has extra ref from the write/commit path to handle handoff
 256                 * between write and commit lists. */
 257                if (test_bit(PG_INODE_REF, &prev->wb_head->wb_flags)) {
 258                        inode = page_file_mapping(req->wb_page)->host;
 259                        set_bit(PG_INODE_REF, &req->wb_flags);
 260                        kref_get(&req->wb_kref);
 261                        atomic_long_inc(&NFS_I(inode)->nrequests);
 262                }
 263        }
 264}
 265
 266/*
 267 * nfs_page_group_destroy - sync the destruction of page groups
 268 * @req - request that no longer needs the page group
 269 *
 270 * releases the page group reference from each member once all
 271 * members have called this function.
 272 */
 273static void
 274nfs_page_group_destroy(struct kref *kref)
 275{
 276        struct nfs_page *req = container_of(kref, struct nfs_page, wb_kref);
 277        struct nfs_page *head = req->wb_head;
 278        struct nfs_page *tmp, *next;
 279
 280        if (!nfs_page_group_sync_on_bit(req, PG_TEARDOWN))
 281                goto out;
 282
 283        tmp = req;
 284        do {
 285                next = tmp->wb_this_page;
 286                /* unlink and free */
 287                tmp->wb_this_page = tmp;
 288                tmp->wb_head = tmp;
 289                nfs_free_request(tmp);
 290                tmp = next;
 291        } while (tmp != req);
 292out:
 293        /* subrequests must release the ref on the head request */
 294        if (head != req)
 295                nfs_release_request(head);
 296}
 297
 298/**
 299 * nfs_create_request - Create an NFS read/write request.
 300 * @ctx: open context to use
 301 * @page: page to write
 302 * @last: last nfs request created for this page group or NULL if head
 303 * @offset: starting offset within the page for the write
 304 * @count: number of bytes to read/write
 305 *
 306 * The page must be locked by the caller. This makes sure we never
 307 * create two different requests for the same page.
 308 * User should ensure it is safe to sleep in this function.
 309 */
 310struct nfs_page *
 311nfs_create_request(struct nfs_open_context *ctx, struct page *page,
 312                   struct nfs_page *last, unsigned int offset,
 313                   unsigned int count)
 314{
 315        struct nfs_page         *req;
 316        struct nfs_lock_context *l_ctx;
 317
 318        if (test_bit(NFS_CONTEXT_BAD, &ctx->flags))
 319                return ERR_PTR(-EBADF);
 320        /* try to allocate the request struct */
 321        req = nfs_page_alloc();
 322        if (req == NULL)
 323                return ERR_PTR(-ENOMEM);
 324
 325        /* get lock context early so we can deal with alloc failures */
 326        l_ctx = nfs_get_lock_context(ctx);
 327        if (IS_ERR(l_ctx)) {
 328                nfs_page_free(req);
 329                return ERR_CAST(l_ctx);
 330        }
 331        req->wb_lock_context = l_ctx;
 332        atomic_inc(&l_ctx->io_count);
 333
 334        /* Initialize the request struct. Initially, we assume a
 335         * long write-back delay. This will be adjusted in
 336         * update_nfs_request below if the region is not locked. */
 337        req->wb_page    = page;
 338        if (page) {
 339                req->wb_index = page_index(page);
 340                get_page(page);
 341        }
 342        req->wb_offset  = offset;
 343        req->wb_pgbase  = offset;
 344        req->wb_bytes   = count;
 345        req->wb_context = get_nfs_open_context(ctx);
 346        kref_init(&req->wb_kref);
 347        nfs_page_group_init(req, last);
 348        return req;
 349}
 350
 351/**
 352 * nfs_unlock_request - Unlock request and wake up sleepers.
 353 * @req:
 354 */
 355void nfs_unlock_request(struct nfs_page *req)
 356{
 357        if (!NFS_WBACK_BUSY(req)) {
 358                printk(KERN_ERR "NFS: Invalid unlock attempted\n");
 359                BUG();
 360        }
 361        smp_mb__before_atomic();
 362        clear_bit(PG_BUSY, &req->wb_flags);
 363        smp_mb__after_atomic();
 364        if (!test_bit(PG_CONTENDED2, &req->wb_flags))
 365                return;
 366        wake_up_bit(&req->wb_flags, PG_BUSY);
 367}
 368
 369/**
 370 * nfs_unlock_and_release_request - Unlock request and release the nfs_page
 371 * @req:
 372 */
 373void nfs_unlock_and_release_request(struct nfs_page *req)
 374{
 375        nfs_unlock_request(req);
 376        nfs_release_request(req);
 377}
 378
 379/*
 380 * nfs_clear_request - Free up all resources allocated to the request
 381 * @req:
 382 *
 383 * Release page and open context resources associated with a read/write
 384 * request after it has completed.
 385 */
 386static void nfs_clear_request(struct nfs_page *req)
 387{
 388        struct page *page = req->wb_page;
 389        struct nfs_open_context *ctx = req->wb_context;
 390        struct nfs_lock_context *l_ctx = req->wb_lock_context;
 391
 392        if (page != NULL) {
 393                put_page(page);
 394                req->wb_page = NULL;
 395        }
 396        if (l_ctx != NULL) {
 397                if (atomic_dec_and_test(&l_ctx->io_count)) {
 398                        wake_up_atomic_t(&l_ctx->io_count);
 399                        if (test_bit(NFS_CONTEXT_UNLOCK, &ctx->flags))
 400                                rpc_wake_up(&NFS_SERVER(d_inode(ctx->dentry))->uoc_rpcwaitq);
 401                }
 402                nfs_put_lock_context(l_ctx);
 403                req->wb_lock_context = NULL;
 404        }
 405        if (ctx != NULL) {
 406                put_nfs_open_context(ctx);
 407                req->wb_context = NULL;
 408        }
 409}
 410
 411/**
 412 * nfs_release_request - Release the count on an NFS read/write request
 413 * @req: request to release
 414 *
 415 * Note: Should never be called with the spinlock held!
 416 */
 417void nfs_free_request(struct nfs_page *req)
 418{
 419        WARN_ON_ONCE(req->wb_this_page != req);
 420
 421        /* extra debug: make sure no sync bits are still set */
 422        WARN_ON_ONCE(test_bit(PG_TEARDOWN, &req->wb_flags));
 423        WARN_ON_ONCE(test_bit(PG_UNLOCKPAGE, &req->wb_flags));
 424        WARN_ON_ONCE(test_bit(PG_UPTODATE, &req->wb_flags));
 425        WARN_ON_ONCE(test_bit(PG_WB_END, &req->wb_flags));
 426        WARN_ON_ONCE(test_bit(PG_REMOVE, &req->wb_flags));
 427
 428        /* Release struct file and open context */
 429        nfs_clear_request(req);
 430        nfs_page_free(req);
 431}
 432
 433void nfs_release_request(struct nfs_page *req)
 434{
 435        kref_put(&req->wb_kref, nfs_page_group_destroy);
 436}
 437EXPORT_SYMBOL_GPL(nfs_release_request);
 438
 439/**
 440 * nfs_wait_on_request - Wait for a request to complete.
 441 * @req: request to wait upon.
 442 *
 443 * Interruptible by fatal signals only.
 444 * The user is responsible for holding a count on the request.
 445 */
 446int
 447nfs_wait_on_request(struct nfs_page *req)
 448{
 449        if (!test_bit(PG_BUSY, &req->wb_flags))
 450                return 0;
 451        set_bit(PG_CONTENDED2, &req->wb_flags);
 452        smp_mb__after_atomic();
 453        return wait_on_bit_io(&req->wb_flags, PG_BUSY,
 454                              TASK_UNINTERRUPTIBLE);
 455}
 456EXPORT_SYMBOL_GPL(nfs_wait_on_request);
 457
 458/*
 459 * nfs_generic_pg_test - determine if requests can be coalesced
 460 * @desc: pointer to descriptor
 461 * @prev: previous request in desc, or NULL
 462 * @req: this request
 463 *
 464 * Returns zero if @req can be coalesced into @desc, otherwise it returns
 465 * the size of the request.
 466 */
 467size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
 468                           struct nfs_page *prev, struct nfs_page *req)
 469{
 470        struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
 471
 472
 473        if (mirror->pg_count > mirror->pg_bsize) {
 474                /* should never happen */
 475                WARN_ON_ONCE(1);
 476                return 0;
 477        }
 478
 479        /*
 480         * Limit the request size so that we can still allocate a page array
 481         * for it without upsetting the slab allocator.
 482         */
 483        if (((mirror->pg_count + req->wb_bytes) >> PAGE_SHIFT) *
 484                        sizeof(struct page *) > PAGE_SIZE)
 485                return 0;
 486
 487        return min(mirror->pg_bsize - mirror->pg_count, (size_t)req->wb_bytes);
 488}
 489EXPORT_SYMBOL_GPL(nfs_generic_pg_test);
 490
 491struct nfs_pgio_header *nfs_pgio_header_alloc(const struct nfs_rw_ops *ops)
 492{
 493        struct nfs_pgio_header *hdr = ops->rw_alloc_header();
 494
 495        if (hdr) {
 496                INIT_LIST_HEAD(&hdr->pages);
 497                spin_lock_init(&hdr->lock);
 498                hdr->rw_ops = ops;
 499        }
 500        return hdr;
 501}
 502EXPORT_SYMBOL_GPL(nfs_pgio_header_alloc);
 503
 504/**
 505 * nfs_pgio_data_destroy - make @hdr suitable for reuse
 506 *
 507 * Frees memory and releases refs from nfs_generic_pgio, so that it may
 508 * be called again.
 509 *
 510 * @hdr: A header that has had nfs_generic_pgio called
 511 */
 512static void nfs_pgio_data_destroy(struct nfs_pgio_header *hdr)
 513{
 514        if (hdr->args.context)
 515                put_nfs_open_context(hdr->args.context);
 516        if (hdr->page_array.pagevec != hdr->page_array.page_array)
 517                kfree(hdr->page_array.pagevec);
 518}
 519
 520/*
 521 * nfs_pgio_header_free - Free a read or write header
 522 * @hdr: The header to free
 523 */
 524void nfs_pgio_header_free(struct nfs_pgio_header *hdr)
 525{
 526        nfs_pgio_data_destroy(hdr);
 527        hdr->rw_ops->rw_free_header(hdr);
 528}
 529EXPORT_SYMBOL_GPL(nfs_pgio_header_free);
 530
 531/**
 532 * nfs_pgio_rpcsetup - Set up arguments for a pageio call
 533 * @hdr: The pageio hdr
 534 * @count: Number of bytes to read
 535 * @offset: Initial offset
 536 * @how: How to commit data (writes only)
 537 * @cinfo: Commit information for the call (writes only)
 538 */
 539static void nfs_pgio_rpcsetup(struct nfs_pgio_header *hdr,
 540                              unsigned int count,
 541                              int how, struct nfs_commit_info *cinfo)
 542{
 543        struct nfs_page *req = hdr->req;
 544
 545        /* Set up the RPC argument and reply structs
 546         * NB: take care not to mess about with hdr->commit et al. */
 547
 548        hdr->args.fh     = NFS_FH(hdr->inode);
 549        hdr->args.offset = req_offset(req);
 550        /* pnfs_set_layoutcommit needs this */
 551        hdr->mds_offset = hdr->args.offset;
 552        hdr->args.pgbase = req->wb_pgbase;
 553        hdr->args.pages  = hdr->page_array.pagevec;
 554        hdr->args.count  = count;
 555        hdr->args.context = get_nfs_open_context(req->wb_context);
 556        hdr->args.lock_context = req->wb_lock_context;
 557        hdr->args.stable  = NFS_UNSTABLE;
 558        switch (how & (FLUSH_STABLE | FLUSH_COND_STABLE)) {
 559        case 0:
 560                break;
 561        case FLUSH_COND_STABLE:
 562                if (nfs_reqs_to_commit(cinfo))
 563                        break;
 564        default:
 565                hdr->args.stable = NFS_FILE_SYNC;
 566        }
 567
 568        hdr->res.fattr   = &hdr->fattr;
 569        hdr->res.count   = count;
 570        hdr->res.eof     = 0;
 571        hdr->res.verf    = &hdr->verf;
 572        nfs_fattr_init(&hdr->fattr);
 573}
 574
 575/**
 576 * nfs_pgio_prepare - Prepare pageio hdr to go over the wire
 577 * @task: The current task
 578 * @calldata: pageio header to prepare
 579 */
 580static void nfs_pgio_prepare(struct rpc_task *task, void *calldata)
 581{
 582        struct nfs_pgio_header *hdr = calldata;
 583        int err;
 584        err = NFS_PROTO(hdr->inode)->pgio_rpc_prepare(task, hdr);
 585        if (err)
 586                rpc_exit(task, err);
 587}
 588
 589int nfs_initiate_pgio(struct rpc_clnt *clnt, struct nfs_pgio_header *hdr,
 590                      struct rpc_cred *cred, const struct nfs_rpc_ops *rpc_ops,
 591                      const struct rpc_call_ops *call_ops, int how, int flags)
 592{
 593        struct rpc_task *task;
 594        struct rpc_message msg = {
 595                .rpc_argp = &hdr->args,
 596                .rpc_resp = &hdr->res,
 597                .rpc_cred = cred,
 598        };
 599        struct rpc_task_setup task_setup_data = {
 600                .rpc_client = clnt,
 601                .task = &hdr->task,
 602                .rpc_message = &msg,
 603                .callback_ops = call_ops,
 604                .callback_data = hdr,
 605                .workqueue = nfsiod_workqueue,
 606                .flags = RPC_TASK_ASYNC | flags,
 607        };
 608        int ret = 0;
 609
 610        hdr->rw_ops->rw_initiate(hdr, &msg, rpc_ops, &task_setup_data, how);
 611
 612        dprintk("NFS: initiated pgio call "
 613                "(req %s/%llu, %u bytes @ offset %llu)\n",
 614                hdr->inode->i_sb->s_id,
 615                (unsigned long long)NFS_FILEID(hdr->inode),
 616                hdr->args.count,
 617                (unsigned long long)hdr->args.offset);
 618
 619        task = rpc_run_task(&task_setup_data);
 620        if (IS_ERR(task)) {
 621                ret = PTR_ERR(task);
 622                goto out;
 623        }
 624        if (how & FLUSH_SYNC) {
 625                ret = rpc_wait_for_completion_task(task);
 626                if (ret == 0)
 627                        ret = task->tk_status;
 628        }
 629        rpc_put_task(task);
 630out:
 631        return ret;
 632}
 633EXPORT_SYMBOL_GPL(nfs_initiate_pgio);
 634
 635/**
 636 * nfs_pgio_error - Clean up from a pageio error
 637 * @desc: IO descriptor
 638 * @hdr: pageio header
 639 */
 640static void nfs_pgio_error(struct nfs_pgio_header *hdr)
 641{
 642        set_bit(NFS_IOHDR_REDO, &hdr->flags);
 643        hdr->completion_ops->completion(hdr);
 644}
 645
 646/**
 647 * nfs_pgio_release - Release pageio data
 648 * @calldata: The pageio header to release
 649 */
 650static void nfs_pgio_release(void *calldata)
 651{
 652        struct nfs_pgio_header *hdr = calldata;
 653        hdr->completion_ops->completion(hdr);
 654}
 655
 656static void nfs_pageio_mirror_init(struct nfs_pgio_mirror *mirror,
 657                                   unsigned int bsize)
 658{
 659        INIT_LIST_HEAD(&mirror->pg_list);
 660        mirror->pg_bytes_written = 0;
 661        mirror->pg_count = 0;
 662        mirror->pg_bsize = bsize;
 663        mirror->pg_base = 0;
 664        mirror->pg_recoalesce = 0;
 665}
 666
 667/**
 668 * nfs_pageio_init - initialise a page io descriptor
 669 * @desc: pointer to descriptor
 670 * @inode: pointer to inode
 671 * @pg_ops: pointer to pageio operations
 672 * @compl_ops: pointer to pageio completion operations
 673 * @rw_ops: pointer to nfs read/write operations
 674 * @bsize: io block size
 675 * @io_flags: extra parameters for the io function
 676 */
 677void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
 678                     struct inode *inode,
 679                     const struct nfs_pageio_ops *pg_ops,
 680                     const struct nfs_pgio_completion_ops *compl_ops,
 681                     const struct nfs_rw_ops *rw_ops,
 682                     size_t bsize,
 683                     int io_flags)
 684{
 685        desc->pg_moreio = 0;
 686        desc->pg_inode = inode;
 687        desc->pg_ops = pg_ops;
 688        desc->pg_completion_ops = compl_ops;
 689        desc->pg_rw_ops = rw_ops;
 690        desc->pg_ioflags = io_flags;
 691        desc->pg_error = 0;
 692        desc->pg_lseg = NULL;
 693        desc->pg_io_completion = NULL;
 694        desc->pg_dreq = NULL;
 695        desc->pg_bsize = bsize;
 696
 697        desc->pg_mirror_count = 1;
 698        desc->pg_mirror_idx = 0;
 699
 700        desc->pg_mirrors_dynamic = NULL;
 701        desc->pg_mirrors = desc->pg_mirrors_static;
 702        nfs_pageio_mirror_init(&desc->pg_mirrors[0], bsize);
 703}
 704
 705/**
 706 * nfs_pgio_result - Basic pageio error handling
 707 * @task: The task that ran
 708 * @calldata: Pageio header to check
 709 */
 710static void nfs_pgio_result(struct rpc_task *task, void *calldata)
 711{
 712        struct nfs_pgio_header *hdr = calldata;
 713        struct inode *inode = hdr->inode;
 714
 715        dprintk("NFS: %s: %5u, (status %d)\n", __func__,
 716                task->tk_pid, task->tk_status);
 717
 718        if (hdr->rw_ops->rw_done(task, hdr, inode) != 0)
 719                return;
 720        if (task->tk_status < 0)
 721                nfs_set_pgio_error(hdr, task->tk_status, hdr->args.offset);
 722        else
 723                hdr->rw_ops->rw_result(task, hdr);
 724}
 725
 726/*
 727 * Create an RPC task for the given read or write request and kick it.
 728 * The page must have been locked by the caller.
 729 *
 730 * It may happen that the page we're passed is not marked dirty.
 731 * This is the case if nfs_updatepage detects a conflicting request
 732 * that has been written but not committed.
 733 */
 734int nfs_generic_pgio(struct nfs_pageio_descriptor *desc,
 735                     struct nfs_pgio_header *hdr)
 736{
 737        struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
 738
 739        struct nfs_page         *req;
 740        struct page             **pages,
 741                                *last_page;
 742        struct list_head *head = &mirror->pg_list;
 743        struct nfs_commit_info cinfo;
 744        struct nfs_page_array *pg_array = &hdr->page_array;
 745        unsigned int pagecount, pageused;
 746        gfp_t gfp_flags = GFP_KERNEL;
 747
 748        pagecount = nfs_page_array_len(mirror->pg_base, mirror->pg_count);
 749        pg_array->npages = pagecount;
 750
 751        if (pagecount <= ARRAY_SIZE(pg_array->page_array))
 752                pg_array->pagevec = pg_array->page_array;
 753        else {
 754                if (hdr->rw_mode == FMODE_WRITE)
 755                        gfp_flags = GFP_NOIO;
 756                pg_array->pagevec = kcalloc(pagecount, sizeof(struct page *), gfp_flags);
 757                if (!pg_array->pagevec) {
 758                        pg_array->npages = 0;
 759                        nfs_pgio_error(hdr);
 760                        desc->pg_error = -ENOMEM;
 761                        return desc->pg_error;
 762                }
 763        }
 764
 765        nfs_init_cinfo(&cinfo, desc->pg_inode, desc->pg_dreq);
 766        pages = hdr->page_array.pagevec;
 767        last_page = NULL;
 768        pageused = 0;
 769        while (!list_empty(head)) {
 770                req = nfs_list_entry(head->next);
 771                nfs_list_remove_request(req);
 772                nfs_list_add_request(req, &hdr->pages);
 773
 774                if (!last_page || last_page != req->wb_page) {
 775                        pageused++;
 776                        if (pageused > pagecount)
 777                                break;
 778                        *pages++ = last_page = req->wb_page;
 779                }
 780        }
 781        if (WARN_ON_ONCE(pageused != pagecount)) {
 782                nfs_pgio_error(hdr);
 783                desc->pg_error = -EINVAL;
 784                return desc->pg_error;
 785        }
 786
 787        if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
 788            (desc->pg_moreio || nfs_reqs_to_commit(&cinfo)))
 789                desc->pg_ioflags &= ~FLUSH_COND_STABLE;
 790
 791        /* Set up the argument struct */
 792        nfs_pgio_rpcsetup(hdr, mirror->pg_count, desc->pg_ioflags, &cinfo);
 793        desc->pg_rpc_callops = &nfs_pgio_common_ops;
 794        return 0;
 795}
 796EXPORT_SYMBOL_GPL(nfs_generic_pgio);
 797
 798static int nfs_generic_pg_pgios(struct nfs_pageio_descriptor *desc)
 799{
 800        struct nfs_pgio_header *hdr;
 801        int ret;
 802
 803        hdr = nfs_pgio_header_alloc(desc->pg_rw_ops);
 804        if (!hdr) {
 805                desc->pg_error = -ENOMEM;
 806                return desc->pg_error;
 807        }
 808        nfs_pgheader_init(desc, hdr, nfs_pgio_header_free);
 809        ret = nfs_generic_pgio(desc, hdr);
 810        if (ret == 0)
 811                ret = nfs_initiate_pgio(NFS_CLIENT(hdr->inode),
 812                                        hdr,
 813                                        hdr->cred,
 814                                        NFS_PROTO(hdr->inode),
 815                                        desc->pg_rpc_callops,
 816                                        desc->pg_ioflags, 0);
 817        return ret;
 818}
 819
 820static struct nfs_pgio_mirror *
 821nfs_pageio_alloc_mirrors(struct nfs_pageio_descriptor *desc,
 822                unsigned int mirror_count)
 823{
 824        struct nfs_pgio_mirror *ret;
 825        unsigned int i;
 826
 827        kfree(desc->pg_mirrors_dynamic);
 828        desc->pg_mirrors_dynamic = NULL;
 829        if (mirror_count == 1)
 830                return desc->pg_mirrors_static;
 831        ret = kmalloc_array(mirror_count, sizeof(*ret), GFP_NOFS);
 832        if (ret != NULL) {
 833                for (i = 0; i < mirror_count; i++)
 834                        nfs_pageio_mirror_init(&ret[i], desc->pg_bsize);
 835                desc->pg_mirrors_dynamic = ret;
 836        }
 837        return ret;
 838}
 839
 840/*
 841 * nfs_pageio_setup_mirroring - determine if mirroring is to be used
 842 *                              by calling the pg_get_mirror_count op
 843 */
 844static void nfs_pageio_setup_mirroring(struct nfs_pageio_descriptor *pgio,
 845                                       struct nfs_page *req)
 846{
 847        unsigned int mirror_count = 1;
 848
 849        if (pgio->pg_ops->pg_get_mirror_count)
 850                mirror_count = pgio->pg_ops->pg_get_mirror_count(pgio, req);
 851        if (mirror_count == pgio->pg_mirror_count || pgio->pg_error < 0)
 852                return;
 853
 854        if (!mirror_count || mirror_count > NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX) {
 855                pgio->pg_error = -EINVAL;
 856                return;
 857        }
 858
 859        pgio->pg_mirrors = nfs_pageio_alloc_mirrors(pgio, mirror_count);
 860        if (pgio->pg_mirrors == NULL) {
 861                pgio->pg_error = -ENOMEM;
 862                pgio->pg_mirrors = pgio->pg_mirrors_static;
 863                mirror_count = 1;
 864        }
 865        pgio->pg_mirror_count = mirror_count;
 866}
 867
 868/*
 869 * nfs_pageio_stop_mirroring - stop using mirroring (set mirror count to 1)
 870 */
 871void nfs_pageio_stop_mirroring(struct nfs_pageio_descriptor *pgio)
 872{
 873        pgio->pg_mirror_count = 1;
 874        pgio->pg_mirror_idx = 0;
 875}
 876
 877static void nfs_pageio_cleanup_mirroring(struct nfs_pageio_descriptor *pgio)
 878{
 879        pgio->pg_mirror_count = 1;
 880        pgio->pg_mirror_idx = 0;
 881        pgio->pg_mirrors = pgio->pg_mirrors_static;
 882        kfree(pgio->pg_mirrors_dynamic);
 883        pgio->pg_mirrors_dynamic = NULL;
 884}
 885
 886static bool nfs_match_lock_context(const struct nfs_lock_context *l1,
 887                const struct nfs_lock_context *l2)
 888{
 889        return l1->lockowner == l2->lockowner;
 890}
 891
 892/**
 893 * nfs_can_coalesce_requests - test two requests for compatibility
 894 * @prev: pointer to nfs_page
 895 * @req: pointer to nfs_page
 896 *
 897 * The nfs_page structures 'prev' and 'req' are compared to ensure that the
 898 * page data area they describe is contiguous, and that their RPC
 899 * credentials, NFSv4 open state, and lockowners are the same.
 900 *
 901 * Return 'true' if this is the case, else return 'false'.
 902 */
 903static bool nfs_can_coalesce_requests(struct nfs_page *prev,
 904                                      struct nfs_page *req,
 905                                      struct nfs_pageio_descriptor *pgio)
 906{
 907        size_t size;
 908        struct file_lock_context *flctx;
 909
 910        if (prev) {
 911                if (!nfs_match_open_context(req->wb_context, prev->wb_context))
 912                        return false;
 913                flctx = d_inode(req->wb_context->dentry)->i_flctx;
 914                if (flctx != NULL &&
 915                    !(list_empty_careful(&flctx->flc_posix) &&
 916                      list_empty_careful(&flctx->flc_flock)) &&
 917                    !nfs_match_lock_context(req->wb_lock_context,
 918                                            prev->wb_lock_context))
 919                        return false;
 920                if (req_offset(req) != req_offset(prev) + prev->wb_bytes)
 921                        return false;
 922                if (req->wb_page == prev->wb_page) {
 923                        if (req->wb_pgbase != prev->wb_pgbase + prev->wb_bytes)
 924                                return false;
 925                } else {
 926                        if (req->wb_pgbase != 0 ||
 927                            prev->wb_pgbase + prev->wb_bytes != PAGE_SIZE)
 928                                return false;
 929                }
 930        }
 931        size = pgio->pg_ops->pg_test(pgio, prev, req);
 932        WARN_ON_ONCE(size > req->wb_bytes);
 933        if (size && size < req->wb_bytes)
 934                req->wb_bytes = size;
 935        return size > 0;
 936}
 937
 938/**
 939 * nfs_pageio_do_add_request - Attempt to coalesce a request into a page list.
 940 * @desc: destination io descriptor
 941 * @req: request
 942 *
 943 * Returns true if the request 'req' was successfully coalesced into the
 944 * existing list of pages 'desc'.
 945 */
 946static int nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc,
 947                                     struct nfs_page *req)
 948{
 949        struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
 950
 951        struct nfs_page *prev = NULL;
 952
 953        if (mirror->pg_count != 0) {
 954                prev = nfs_list_entry(mirror->pg_list.prev);
 955        } else {
 956                if (desc->pg_ops->pg_init)
 957                        desc->pg_ops->pg_init(desc, req);
 958                if (desc->pg_error < 0)
 959                        return 0;
 960                mirror->pg_base = req->wb_pgbase;
 961        }
 962        if (!nfs_can_coalesce_requests(prev, req, desc))
 963                return 0;
 964        nfs_list_remove_request(req);
 965        nfs_list_add_request(req, &mirror->pg_list);
 966        mirror->pg_count += req->wb_bytes;
 967        return 1;
 968}
 969
 970/*
 971 * Helper for nfs_pageio_add_request and nfs_pageio_complete
 972 */
 973static void nfs_pageio_doio(struct nfs_pageio_descriptor *desc)
 974{
 975        struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
 976
 977
 978        if (!list_empty(&mirror->pg_list)) {
 979                int error = desc->pg_ops->pg_doio(desc);
 980                if (error < 0)
 981                        desc->pg_error = error;
 982                else
 983                        mirror->pg_bytes_written += mirror->pg_count;
 984        }
 985        if (list_empty(&mirror->pg_list)) {
 986                mirror->pg_count = 0;
 987                mirror->pg_base = 0;
 988        }
 989}
 990
 991/**
 992 * nfs_pageio_add_request - Attempt to coalesce a request into a page list.
 993 * @desc: destination io descriptor
 994 * @req: request
 995 *
 996 * This may split a request into subrequests which are all part of the
 997 * same page group.
 998 *
 999 * Returns true if the request 'req' was successfully coalesced into the
1000 * existing list of pages 'desc'.
1001 */
1002static int __nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
1003                           struct nfs_page *req)
1004{
1005        struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1006
1007        struct nfs_page *subreq;
1008        unsigned int bytes_left = 0;
1009        unsigned int offset, pgbase;
1010
1011        nfs_page_group_lock(req);
1012
1013        subreq = req;
1014        bytes_left = subreq->wb_bytes;
1015        offset = subreq->wb_offset;
1016        pgbase = subreq->wb_pgbase;
1017
1018        do {
1019                if (!nfs_pageio_do_add_request(desc, subreq)) {
1020                        /* make sure pg_test call(s) did nothing */
1021                        WARN_ON_ONCE(subreq->wb_bytes != bytes_left);
1022                        WARN_ON_ONCE(subreq->wb_offset != offset);
1023                        WARN_ON_ONCE(subreq->wb_pgbase != pgbase);
1024
1025                        nfs_page_group_unlock(req);
1026                        desc->pg_moreio = 1;
1027                        nfs_pageio_doio(desc);
1028                        if (desc->pg_error < 0)
1029                                return 0;
1030                        if (mirror->pg_recoalesce)
1031                                return 0;
1032                        /* retry add_request for this subreq */
1033                        nfs_page_group_lock(req);
1034                        continue;
1035                }
1036
1037                /* check for buggy pg_test call(s) */
1038                WARN_ON_ONCE(subreq->wb_bytes + subreq->wb_pgbase > PAGE_SIZE);
1039                WARN_ON_ONCE(subreq->wb_bytes > bytes_left);
1040                WARN_ON_ONCE(subreq->wb_bytes == 0);
1041
1042                bytes_left -= subreq->wb_bytes;
1043                offset += subreq->wb_bytes;
1044                pgbase += subreq->wb_bytes;
1045
1046                if (bytes_left) {
1047                        subreq = nfs_create_request(req->wb_context,
1048                                        req->wb_page,
1049                                        subreq, pgbase, bytes_left);
1050                        if (IS_ERR(subreq))
1051                                goto err_ptr;
1052                        nfs_lock_request(subreq);
1053                        subreq->wb_offset  = offset;
1054                        subreq->wb_index = req->wb_index;
1055                }
1056        } while (bytes_left > 0);
1057
1058        nfs_page_group_unlock(req);
1059        return 1;
1060err_ptr:
1061        desc->pg_error = PTR_ERR(subreq);
1062        nfs_page_group_unlock(req);
1063        return 0;
1064}
1065
1066static int nfs_do_recoalesce(struct nfs_pageio_descriptor *desc)
1067{
1068        struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1069        LIST_HEAD(head);
1070
1071        do {
1072                list_splice_init(&mirror->pg_list, &head);
1073                mirror->pg_bytes_written -= mirror->pg_count;
1074                mirror->pg_count = 0;
1075                mirror->pg_base = 0;
1076                mirror->pg_recoalesce = 0;
1077
1078                while (!list_empty(&head)) {
1079                        struct nfs_page *req;
1080
1081                        req = list_first_entry(&head, struct nfs_page, wb_list);
1082                        nfs_list_remove_request(req);
1083                        if (__nfs_pageio_add_request(desc, req))
1084                                continue;
1085                        if (desc->pg_error < 0) {
1086                                list_splice_tail(&head, &mirror->pg_list);
1087                                mirror->pg_recoalesce = 1;
1088                                return 0;
1089                        }
1090                        break;
1091                }
1092        } while (mirror->pg_recoalesce);
1093        return 1;
1094}
1095
1096static int nfs_pageio_add_request_mirror(struct nfs_pageio_descriptor *desc,
1097                struct nfs_page *req)
1098{
1099        int ret;
1100
1101        do {
1102                ret = __nfs_pageio_add_request(desc, req);
1103                if (ret)
1104                        break;
1105                if (desc->pg_error < 0)
1106                        break;
1107                ret = nfs_do_recoalesce(desc);
1108        } while (ret);
1109
1110        return ret;
1111}
1112
1113int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
1114                           struct nfs_page *req)
1115{
1116        u32 midx;
1117        unsigned int pgbase, offset, bytes;
1118        struct nfs_page *dupreq, *lastreq;
1119
1120        pgbase = req->wb_pgbase;
1121        offset = req->wb_offset;
1122        bytes = req->wb_bytes;
1123
1124        nfs_pageio_setup_mirroring(desc, req);
1125        if (desc->pg_error < 0)
1126                goto out_failed;
1127
1128        for (midx = 0; midx < desc->pg_mirror_count; midx++) {
1129                if (midx) {
1130                        nfs_page_group_lock(req);
1131
1132                        /* find the last request */
1133                        for (lastreq = req->wb_head;
1134                             lastreq->wb_this_page != req->wb_head;
1135                             lastreq = lastreq->wb_this_page)
1136                                ;
1137
1138                        dupreq = nfs_create_request(req->wb_context,
1139                                        req->wb_page, lastreq, pgbase, bytes);
1140
1141                        if (IS_ERR(dupreq)) {
1142                                nfs_page_group_unlock(req);
1143                                desc->pg_error = PTR_ERR(dupreq);
1144                                goto out_failed;
1145                        }
1146
1147                        nfs_lock_request(dupreq);
1148                        nfs_page_group_unlock(req);
1149                        dupreq->wb_offset = offset;
1150                        dupreq->wb_index = req->wb_index;
1151                } else
1152                        dupreq = req;
1153
1154                if (nfs_pgio_has_mirroring(desc))
1155                        desc->pg_mirror_idx = midx;
1156                if (!nfs_pageio_add_request_mirror(desc, dupreq))
1157                        goto out_failed;
1158        }
1159
1160        return 1;
1161
1162out_failed:
1163        /*
1164         * We might have failed before sending any reqs over wire.
1165         * Clean up rest of the reqs in mirror pg_list.
1166         */
1167        if (desc->pg_error) {
1168                struct nfs_pgio_mirror *mirror;
1169                void (*func)(struct list_head *);
1170
1171                /* remember fatal errors */
1172                if (nfs_error_is_fatal(desc->pg_error))
1173                        nfs_context_set_write_error(req->wb_context,
1174                                                    desc->pg_error);
1175
1176                func = desc->pg_completion_ops->error_cleanup;
1177                for (midx = 0; midx < desc->pg_mirror_count; midx++) {
1178                        mirror = &desc->pg_mirrors[midx];
1179                        func(&mirror->pg_list);
1180                }
1181        }
1182        return 0;
1183}
1184
1185/*
1186 * nfs_pageio_complete_mirror - Complete I/O on the current mirror of an
1187 *                              nfs_pageio_descriptor
1188 * @desc: pointer to io descriptor
1189 * @mirror_idx: pointer to mirror index
1190 */
1191static void nfs_pageio_complete_mirror(struct nfs_pageio_descriptor *desc,
1192                                       u32 mirror_idx)
1193{
1194        struct nfs_pgio_mirror *mirror = &desc->pg_mirrors[mirror_idx];
1195        u32 restore_idx = desc->pg_mirror_idx;
1196
1197        if (nfs_pgio_has_mirroring(desc))
1198                desc->pg_mirror_idx = mirror_idx;
1199        for (;;) {
1200                nfs_pageio_doio(desc);
1201                if (!mirror->pg_recoalesce)
1202                        break;
1203                if (!nfs_do_recoalesce(desc))
1204                        break;
1205        }
1206        desc->pg_mirror_idx = restore_idx;
1207}
1208
1209/*
1210 * nfs_pageio_resend - Transfer requests to new descriptor and resend
1211 * @hdr - the pgio header to move request from
1212 * @desc - the pageio descriptor to add requests to
1213 *
1214 * Try to move each request (nfs_page) from @hdr to @desc then attempt
1215 * to send them.
1216 *
1217 * Returns 0 on success and < 0 on error.
1218 */
1219int nfs_pageio_resend(struct nfs_pageio_descriptor *desc,
1220                      struct nfs_pgio_header *hdr)
1221{
1222        LIST_HEAD(failed);
1223
1224        desc->pg_io_completion = hdr->io_completion;
1225        desc->pg_dreq = hdr->dreq;
1226        while (!list_empty(&hdr->pages)) {
1227                struct nfs_page *req = nfs_list_entry(hdr->pages.next);
1228
1229                nfs_list_remove_request(req);
1230                if (!nfs_pageio_add_request(desc, req))
1231                        nfs_list_add_request(req, &failed);
1232        }
1233        nfs_pageio_complete(desc);
1234        if (!list_empty(&failed)) {
1235                list_move(&failed, &hdr->pages);
1236                return desc->pg_error < 0 ? desc->pg_error : -EIO;
1237        }
1238        return 0;
1239}
1240EXPORT_SYMBOL_GPL(nfs_pageio_resend);
1241
1242/**
1243 * nfs_pageio_complete - Complete I/O then cleanup an nfs_pageio_descriptor
1244 * @desc: pointer to io descriptor
1245 */
1246void nfs_pageio_complete(struct nfs_pageio_descriptor *desc)
1247{
1248        u32 midx;
1249
1250        for (midx = 0; midx < desc->pg_mirror_count; midx++)
1251                nfs_pageio_complete_mirror(desc, midx);
1252
1253        if (desc->pg_ops->pg_cleanup)
1254                desc->pg_ops->pg_cleanup(desc);
1255        nfs_pageio_cleanup_mirroring(desc);
1256}
1257
1258/**
1259 * nfs_pageio_cond_complete - Conditional I/O completion
1260 * @desc: pointer to io descriptor
1261 * @index: page index
1262 *
1263 * It is important to ensure that processes don't try to take locks
1264 * on non-contiguous ranges of pages as that might deadlock. This
1265 * function should be called before attempting to wait on a locked
1266 * nfs_page. It will complete the I/O if the page index 'index'
1267 * is not contiguous with the existing list of pages in 'desc'.
1268 */
1269void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *desc, pgoff_t index)
1270{
1271        struct nfs_pgio_mirror *mirror;
1272        struct nfs_page *prev;
1273        u32 midx;
1274
1275        for (midx = 0; midx < desc->pg_mirror_count; midx++) {
1276                mirror = &desc->pg_mirrors[midx];
1277                if (!list_empty(&mirror->pg_list)) {
1278                        prev = nfs_list_entry(mirror->pg_list.prev);
1279                        if (index != prev->wb_index + 1) {
1280                                nfs_pageio_complete(desc);
1281                                break;
1282                        }
1283                }
1284        }
1285}
1286
1287int __init nfs_init_nfspagecache(void)
1288{
1289        nfs_page_cachep = kmem_cache_create("nfs_page",
1290                                            sizeof(struct nfs_page),
1291                                            0, SLAB_HWCACHE_ALIGN,
1292                                            NULL);
1293        if (nfs_page_cachep == NULL)
1294                return -ENOMEM;
1295
1296        return 0;
1297}
1298
1299void nfs_destroy_nfspagecache(void)
1300{
1301        kmem_cache_destroy(nfs_page_cachep);
1302}
1303
1304static const struct rpc_call_ops nfs_pgio_common_ops = {
1305        .rpc_call_prepare = nfs_pgio_prepare,
1306        .rpc_call_done = nfs_pgio_result,
1307        .rpc_release = nfs_pgio_release,
1308};
1309
1310const struct nfs_pageio_ops nfs_pgio_rw_ops = {
1311        .pg_test = nfs_generic_pg_test,
1312        .pg_doio = nfs_generic_pg_pgios,
1313};
1314