linux/net/sunrpc/cache.c
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   1/*
   2 * net/sunrpc/cache.c
   3 *
   4 * Generic code for various authentication-related caches
   5 * used by sunrpc clients and servers.
   6 *
   7 * Copyright (C) 2002 Neil Brown <neilb@cse.unsw.edu.au>
   8 *
   9 * Released under terms in GPL version 2.  See COPYING.
  10 *
  11 */
  12
  13#include <linux/types.h>
  14#include <linux/fs.h>
  15#include <linux/file.h>
  16#include <linux/slab.h>
  17#include <linux/signal.h>
  18#include <linux/sched.h>
  19#include <linux/kmod.h>
  20#include <linux/list.h>
  21#include <linux/module.h>
  22#include <linux/ctype.h>
  23#include <asm/uaccess.h>
  24#include <linux/poll.h>
  25#include <linux/seq_file.h>
  26#include <linux/proc_fs.h>
  27#include <linux/net.h>
  28#include <linux/workqueue.h>
  29#include <linux/mutex.h>
  30#include <linux/pagemap.h>
  31#include <asm/ioctls.h>
  32#include <linux/sunrpc/types.h>
  33#include <linux/sunrpc/cache.h>
  34#include <linux/sunrpc/stats.h>
  35#include <linux/sunrpc/rpc_pipe_fs.h>
  36#include "netns.h"
  37
  38#define  RPCDBG_FACILITY RPCDBG_CACHE
  39
  40static bool cache_defer_req(struct cache_req *req, struct cache_head *item);
  41static void cache_revisit_request(struct cache_head *item);
  42
  43static void cache_init(struct cache_head *h)
  44{
  45        time_t now = seconds_since_boot();
  46        h->next = NULL;
  47        h->flags = 0;
  48        kref_init(&h->ref);
  49        h->expiry_time = now + CACHE_NEW_EXPIRY;
  50        h->last_refresh = now;
  51}
  52
  53static inline int cache_is_expired(struct cache_detail *detail, struct cache_head *h)
  54{
  55        return  (h->expiry_time < seconds_since_boot()) ||
  56                (detail->flush_time > h->last_refresh);
  57}
  58
  59struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail,
  60                                       struct cache_head *key, int hash)
  61{
  62        struct cache_head **head,  **hp;
  63        struct cache_head *new = NULL, *freeme = NULL;
  64
  65        head = &detail->hash_table[hash];
  66
  67        read_lock(&detail->hash_lock);
  68
  69        for (hp=head; *hp != NULL ; hp = &(*hp)->next) {
  70                struct cache_head *tmp = *hp;
  71                if (detail->match(tmp, key)) {
  72                        if (cache_is_expired(detail, tmp))
  73                                /* This entry is expired, we will discard it. */
  74                                break;
  75                        cache_get(tmp);
  76                        read_unlock(&detail->hash_lock);
  77                        return tmp;
  78                }
  79        }
  80        read_unlock(&detail->hash_lock);
  81        /* Didn't find anything, insert an empty entry */
  82
  83        new = detail->alloc();
  84        if (!new)
  85                return NULL;
  86        /* must fully initialise 'new', else
  87         * we might get lose if we need to
  88         * cache_put it soon.
  89         */
  90        cache_init(new);
  91        detail->init(new, key);
  92
  93        write_lock(&detail->hash_lock);
  94
  95        /* check if entry appeared while we slept */
  96        for (hp=head; *hp != NULL ; hp = &(*hp)->next) {
  97                struct cache_head *tmp = *hp;
  98                if (detail->match(tmp, key)) {
  99                        if (cache_is_expired(detail, tmp)) {
 100                                *hp = tmp->next;
 101                                tmp->next = NULL;
 102                                detail->entries --;
 103                                freeme = tmp;
 104                                break;
 105                        }
 106                        cache_get(tmp);
 107                        write_unlock(&detail->hash_lock);
 108                        cache_put(new, detail);
 109                        return tmp;
 110                }
 111        }
 112        new->next = *head;
 113        *head = new;
 114        detail->entries++;
 115        cache_get(new);
 116        write_unlock(&detail->hash_lock);
 117
 118        if (freeme)
 119                cache_put(freeme, detail);
 120        return new;
 121}
 122EXPORT_SYMBOL_GPL(sunrpc_cache_lookup);
 123
 124
 125static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch);
 126
 127static void cache_fresh_locked(struct cache_head *head, time_t expiry)
 128{
 129        head->expiry_time = expiry;
 130        head->last_refresh = seconds_since_boot();
 131        smp_wmb(); /* paired with smp_rmb() in cache_is_valid() */
 132        set_bit(CACHE_VALID, &head->flags);
 133}
 134
 135static void cache_fresh_unlocked(struct cache_head *head,
 136                                 struct cache_detail *detail)
 137{
 138        if (test_and_clear_bit(CACHE_PENDING, &head->flags)) {
 139                cache_revisit_request(head);
 140                cache_dequeue(detail, head);
 141        }
 142}
 143
 144struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
 145                                       struct cache_head *new, struct cache_head *old, int hash)
 146{
 147        /* The 'old' entry is to be replaced by 'new'.
 148         * If 'old' is not VALID, we update it directly,
 149         * otherwise we need to replace it
 150         */
 151        struct cache_head **head;
 152        struct cache_head *tmp;
 153
 154        if (!test_bit(CACHE_VALID, &old->flags)) {
 155                write_lock(&detail->hash_lock);
 156                if (!test_bit(CACHE_VALID, &old->flags)) {
 157                        if (test_bit(CACHE_NEGATIVE, &new->flags))
 158                                set_bit(CACHE_NEGATIVE, &old->flags);
 159                        else
 160                                detail->update(old, new);
 161                        cache_fresh_locked(old, new->expiry_time);
 162                        write_unlock(&detail->hash_lock);
 163                        cache_fresh_unlocked(old, detail);
 164                        return old;
 165                }
 166                write_unlock(&detail->hash_lock);
 167        }
 168        /* We need to insert a new entry */
 169        tmp = detail->alloc();
 170        if (!tmp) {
 171                cache_put(old, detail);
 172                return NULL;
 173        }
 174        cache_init(tmp);
 175        detail->init(tmp, old);
 176        head = &detail->hash_table[hash];
 177
 178        write_lock(&detail->hash_lock);
 179        if (test_bit(CACHE_NEGATIVE, &new->flags))
 180                set_bit(CACHE_NEGATIVE, &tmp->flags);
 181        else
 182                detail->update(tmp, new);
 183        tmp->next = *head;
 184        *head = tmp;
 185        detail->entries++;
 186        cache_get(tmp);
 187        cache_fresh_locked(tmp, new->expiry_time);
 188        cache_fresh_locked(old, 0);
 189        write_unlock(&detail->hash_lock);
 190        cache_fresh_unlocked(tmp, detail);
 191        cache_fresh_unlocked(old, detail);
 192        cache_put(old, detail);
 193        return tmp;
 194}
 195EXPORT_SYMBOL_GPL(sunrpc_cache_update);
 196
 197static int cache_make_upcall(struct cache_detail *cd, struct cache_head *h)
 198{
 199        if (!cd->cache_upcall)
 200                return -EINVAL;
 201        return cd->cache_upcall(cd, h);
 202}
 203
 204static inline int cache_is_valid(struct cache_detail *detail, struct cache_head *h)
 205{
 206        if (!test_bit(CACHE_VALID, &h->flags))
 207                return -EAGAIN;
 208        else {
 209                /* entry is valid */
 210                if (test_bit(CACHE_NEGATIVE, &h->flags))
 211                        return -ENOENT;
 212                else {
 213                        /*
 214                         * In combination with write barrier in
 215                         * sunrpc_cache_update, ensures that anyone
 216                         * using the cache entry after this sees the
 217                         * updated contents:
 218                         */
 219                        smp_rmb();
 220                        return 0;
 221                }
 222        }
 223}
 224
 225static int try_to_negate_entry(struct cache_detail *detail, struct cache_head *h)
 226{
 227        int rv;
 228
 229        write_lock(&detail->hash_lock);
 230        rv = cache_is_valid(detail, h);
 231        if (rv != -EAGAIN) {
 232                write_unlock(&detail->hash_lock);
 233                return rv;
 234        }
 235        set_bit(CACHE_NEGATIVE, &h->flags);
 236        cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY);
 237        write_unlock(&detail->hash_lock);
 238        cache_fresh_unlocked(h, detail);
 239        return -ENOENT;
 240}
 241
 242/*
 243 * This is the generic cache management routine for all
 244 * the authentication caches.
 245 * It checks the currency of a cache item and will (later)
 246 * initiate an upcall to fill it if needed.
 247 *
 248 *
 249 * Returns 0 if the cache_head can be used, or cache_puts it and returns
 250 * -EAGAIN if upcall is pending and request has been queued
 251 * -ETIMEDOUT if upcall failed or request could not be queue or
 252 *           upcall completed but item is still invalid (implying that
 253 *           the cache item has been replaced with a newer one).
 254 * -ENOENT if cache entry was negative
 255 */
 256int cache_check(struct cache_detail *detail,
 257                    struct cache_head *h, struct cache_req *rqstp)
 258{
 259        int rv;
 260        long refresh_age, age;
 261
 262        /* First decide return status as best we can */
 263        rv = cache_is_valid(detail, h);
 264
 265        /* now see if we want to start an upcall */
 266        refresh_age = (h->expiry_time - h->last_refresh);
 267        age = seconds_since_boot() - h->last_refresh;
 268
 269        if (rqstp == NULL) {
 270                if (rv == -EAGAIN)
 271                        rv = -ENOENT;
 272        } else if (rv == -EAGAIN || age > refresh_age/2) {
 273                dprintk("RPC:       Want update, refage=%ld, age=%ld\n",
 274                                refresh_age, age);
 275                if (!test_and_set_bit(CACHE_PENDING, &h->flags)) {
 276                        switch (cache_make_upcall(detail, h)) {
 277                        case -EINVAL:
 278                                clear_bit(CACHE_PENDING, &h->flags);
 279                                cache_revisit_request(h);
 280                                rv = try_to_negate_entry(detail, h);
 281                                break;
 282                        case -EAGAIN:
 283                                clear_bit(CACHE_PENDING, &h->flags);
 284                                cache_revisit_request(h);
 285                                break;
 286                        }
 287                }
 288        }
 289
 290        if (rv == -EAGAIN) {
 291                if (!cache_defer_req(rqstp, h)) {
 292                        /*
 293                         * Request was not deferred; handle it as best
 294                         * we can ourselves:
 295                         */
 296                        rv = cache_is_valid(detail, h);
 297                        if (rv == -EAGAIN)
 298                                rv = -ETIMEDOUT;
 299                }
 300        }
 301        if (rv)
 302                cache_put(h, detail);
 303        return rv;
 304}
 305EXPORT_SYMBOL_GPL(cache_check);
 306
 307/*
 308 * caches need to be periodically cleaned.
 309 * For this we maintain a list of cache_detail and
 310 * a current pointer into that list and into the table
 311 * for that entry.
 312 *
 313 * Each time clean_cache is called it finds the next non-empty entry
 314 * in the current table and walks the list in that entry
 315 * looking for entries that can be removed.
 316 *
 317 * An entry gets removed if:
 318 * - The expiry is before current time
 319 * - The last_refresh time is before the flush_time for that cache
 320 *
 321 * later we might drop old entries with non-NEVER expiry if that table
 322 * is getting 'full' for some definition of 'full'
 323 *
 324 * The question of "how often to scan a table" is an interesting one
 325 * and is answered in part by the use of the "nextcheck" field in the
 326 * cache_detail.
 327 * When a scan of a table begins, the nextcheck field is set to a time
 328 * that is well into the future.
 329 * While scanning, if an expiry time is found that is earlier than the
 330 * current nextcheck time, nextcheck is set to that expiry time.
 331 * If the flush_time is ever set to a time earlier than the nextcheck
 332 * time, the nextcheck time is then set to that flush_time.
 333 *
 334 * A table is then only scanned if the current time is at least
 335 * the nextcheck time.
 336 *
 337 */
 338
 339static LIST_HEAD(cache_list);
 340static DEFINE_SPINLOCK(cache_list_lock);
 341static struct cache_detail *current_detail;
 342static int current_index;
 343
 344static void do_cache_clean(struct work_struct *work);
 345static struct delayed_work cache_cleaner;
 346
 347void sunrpc_init_cache_detail(struct cache_detail *cd)
 348{
 349        rwlock_init(&cd->hash_lock);
 350        INIT_LIST_HEAD(&cd->queue);
 351        spin_lock(&cache_list_lock);
 352        cd->nextcheck = 0;
 353        cd->entries = 0;
 354        atomic_set(&cd->readers, 0);
 355        cd->last_close = 0;
 356        cd->last_warn = -1;
 357        list_add(&cd->others, &cache_list);
 358        spin_unlock(&cache_list_lock);
 359
 360        /* start the cleaning process */
 361        schedule_delayed_work(&cache_cleaner, 0);
 362}
 363EXPORT_SYMBOL_GPL(sunrpc_init_cache_detail);
 364
 365void sunrpc_destroy_cache_detail(struct cache_detail *cd)
 366{
 367        cache_purge(cd);
 368        spin_lock(&cache_list_lock);
 369        write_lock(&cd->hash_lock);
 370        if (cd->entries || atomic_read(&cd->inuse)) {
 371                write_unlock(&cd->hash_lock);
 372                spin_unlock(&cache_list_lock);
 373                goto out;
 374        }
 375        if (current_detail == cd)
 376                current_detail = NULL;
 377        list_del_init(&cd->others);
 378        write_unlock(&cd->hash_lock);
 379        spin_unlock(&cache_list_lock);
 380        if (list_empty(&cache_list)) {
 381                /* module must be being unloaded so its safe to kill the worker */
 382                cancel_delayed_work_sync(&cache_cleaner);
 383        }
 384        return;
 385out:
 386        printk(KERN_ERR "nfsd: failed to unregister %s cache\n", cd->name);
 387}
 388EXPORT_SYMBOL_GPL(sunrpc_destroy_cache_detail);
 389
 390/* clean cache tries to find something to clean
 391 * and cleans it.
 392 * It returns 1 if it cleaned something,
 393 *            0 if it didn't find anything this time
 394 *           -1 if it fell off the end of the list.
 395 */
 396static int cache_clean(void)
 397{
 398        int rv = 0;
 399        struct list_head *next;
 400
 401        spin_lock(&cache_list_lock);
 402
 403        /* find a suitable table if we don't already have one */
 404        while (current_detail == NULL ||
 405            current_index >= current_detail->hash_size) {
 406                if (current_detail)
 407                        next = current_detail->others.next;
 408                else
 409                        next = cache_list.next;
 410                if (next == &cache_list) {
 411                        current_detail = NULL;
 412                        spin_unlock(&cache_list_lock);
 413                        return -1;
 414                }
 415                current_detail = list_entry(next, struct cache_detail, others);
 416                if (current_detail->nextcheck > seconds_since_boot())
 417                        current_index = current_detail->hash_size;
 418                else {
 419                        current_index = 0;
 420                        current_detail->nextcheck = seconds_since_boot()+30*60;
 421                }
 422        }
 423
 424        /* find a non-empty bucket in the table */
 425        while (current_detail &&
 426               current_index < current_detail->hash_size &&
 427               current_detail->hash_table[current_index] == NULL)
 428                current_index++;
 429
 430        /* find a cleanable entry in the bucket and clean it, or set to next bucket */
 431
 432        if (current_detail && current_index < current_detail->hash_size) {
 433                struct cache_head *ch, **cp;
 434                struct cache_detail *d;
 435
 436                write_lock(&current_detail->hash_lock);
 437
 438                /* Ok, now to clean this strand */
 439
 440                cp = & current_detail->hash_table[current_index];
 441                for (ch = *cp ; ch ; cp = & ch->next, ch = *cp) {
 442                        if (current_detail->nextcheck > ch->expiry_time)
 443                                current_detail->nextcheck = ch->expiry_time+1;
 444                        if (!cache_is_expired(current_detail, ch))
 445                                continue;
 446
 447                        *cp = ch->next;
 448                        ch->next = NULL;
 449                        current_detail->entries--;
 450                        rv = 1;
 451                        break;
 452                }
 453
 454                write_unlock(&current_detail->hash_lock);
 455                d = current_detail;
 456                if (!ch)
 457                        current_index ++;
 458                spin_unlock(&cache_list_lock);
 459                if (ch) {
 460                        if (test_and_clear_bit(CACHE_PENDING, &ch->flags))
 461                                cache_dequeue(current_detail, ch);
 462                        cache_revisit_request(ch);
 463                        cache_put(ch, d);
 464                }
 465        } else
 466                spin_unlock(&cache_list_lock);
 467
 468        return rv;
 469}
 470
 471/*
 472 * We want to regularly clean the cache, so we need to schedule some work ...
 473 */
 474static void do_cache_clean(struct work_struct *work)
 475{
 476        int delay = 5;
 477        if (cache_clean() == -1)
 478                delay = round_jiffies_relative(30*HZ);
 479
 480        if (list_empty(&cache_list))
 481                delay = 0;
 482
 483        if (delay)
 484                schedule_delayed_work(&cache_cleaner, delay);
 485}
 486
 487
 488/*
 489 * Clean all caches promptly.  This just calls cache_clean
 490 * repeatedly until we are sure that every cache has had a chance to
 491 * be fully cleaned
 492 */
 493void cache_flush(void)
 494{
 495        while (cache_clean() != -1)
 496                cond_resched();
 497        while (cache_clean() != -1)
 498                cond_resched();
 499}
 500EXPORT_SYMBOL_GPL(cache_flush);
 501
 502void cache_purge(struct cache_detail *detail)
 503{
 504        detail->flush_time = LONG_MAX;
 505        detail->nextcheck = seconds_since_boot();
 506        cache_flush();
 507        detail->flush_time = 1;
 508}
 509EXPORT_SYMBOL_GPL(cache_purge);
 510
 511
 512/*
 513 * Deferral and Revisiting of Requests.
 514 *
 515 * If a cache lookup finds a pending entry, we
 516 * need to defer the request and revisit it later.
 517 * All deferred requests are stored in a hash table,
 518 * indexed by "struct cache_head *".
 519 * As it may be wasteful to store a whole request
 520 * structure, we allow the request to provide a
 521 * deferred form, which must contain a
 522 * 'struct cache_deferred_req'
 523 * This cache_deferred_req contains a method to allow
 524 * it to be revisited when cache info is available
 525 */
 526
 527#define DFR_HASHSIZE    (PAGE_SIZE/sizeof(struct list_head))
 528#define DFR_HASH(item)  ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE)
 529
 530#define DFR_MAX 300     /* ??? */
 531
 532static DEFINE_SPINLOCK(cache_defer_lock);
 533static LIST_HEAD(cache_defer_list);
 534static struct hlist_head cache_defer_hash[DFR_HASHSIZE];
 535static int cache_defer_cnt;
 536
 537static void __unhash_deferred_req(struct cache_deferred_req *dreq)
 538{
 539        hlist_del_init(&dreq->hash);
 540        if (!list_empty(&dreq->recent)) {
 541                list_del_init(&dreq->recent);
 542                cache_defer_cnt--;
 543        }
 544}
 545
 546static void __hash_deferred_req(struct cache_deferred_req *dreq, struct cache_head *item)
 547{
 548        int hash = DFR_HASH(item);
 549
 550        INIT_LIST_HEAD(&dreq->recent);
 551        hlist_add_head(&dreq->hash, &cache_defer_hash[hash]);
 552}
 553
 554static void setup_deferral(struct cache_deferred_req *dreq,
 555                           struct cache_head *item,
 556                           int count_me)
 557{
 558
 559        dreq->item = item;
 560
 561        spin_lock(&cache_defer_lock);
 562
 563        __hash_deferred_req(dreq, item);
 564
 565        if (count_me) {
 566                cache_defer_cnt++;
 567                list_add(&dreq->recent, &cache_defer_list);
 568        }
 569
 570        spin_unlock(&cache_defer_lock);
 571
 572}
 573
 574struct thread_deferred_req {
 575        struct cache_deferred_req handle;
 576        struct completion completion;
 577};
 578
 579static void cache_restart_thread(struct cache_deferred_req *dreq, int too_many)
 580{
 581        struct thread_deferred_req *dr =
 582                container_of(dreq, struct thread_deferred_req, handle);
 583        complete(&dr->completion);
 584}
 585
 586static void cache_wait_req(struct cache_req *req, struct cache_head *item)
 587{
 588        struct thread_deferred_req sleeper;
 589        struct cache_deferred_req *dreq = &sleeper.handle;
 590
 591        sleeper.completion = COMPLETION_INITIALIZER_ONSTACK(sleeper.completion);
 592        dreq->revisit = cache_restart_thread;
 593
 594        setup_deferral(dreq, item, 0);
 595
 596        if (!test_bit(CACHE_PENDING, &item->flags) ||
 597            wait_for_completion_interruptible_timeout(
 598                    &sleeper.completion, req->thread_wait) <= 0) {
 599                /* The completion wasn't completed, so we need
 600                 * to clean up
 601                 */
 602                spin_lock(&cache_defer_lock);
 603                if (!hlist_unhashed(&sleeper.handle.hash)) {
 604                        __unhash_deferred_req(&sleeper.handle);
 605                        spin_unlock(&cache_defer_lock);
 606                } else {
 607                        /* cache_revisit_request already removed
 608                         * this from the hash table, but hasn't
 609                         * called ->revisit yet.  It will very soon
 610                         * and we need to wait for it.
 611                         */
 612                        spin_unlock(&cache_defer_lock);
 613                        wait_for_completion(&sleeper.completion);
 614                }
 615        }
 616}
 617
 618static void cache_limit_defers(void)
 619{
 620        /* Make sure we haven't exceed the limit of allowed deferred
 621         * requests.
 622         */
 623        struct cache_deferred_req *discard = NULL;
 624
 625        if (cache_defer_cnt <= DFR_MAX)
 626                return;
 627
 628        spin_lock(&cache_defer_lock);
 629
 630        /* Consider removing either the first or the last */
 631        if (cache_defer_cnt > DFR_MAX) {
 632                if (net_random() & 1)
 633                        discard = list_entry(cache_defer_list.next,
 634                                             struct cache_deferred_req, recent);
 635                else
 636                        discard = list_entry(cache_defer_list.prev,
 637                                             struct cache_deferred_req, recent);
 638                __unhash_deferred_req(discard);
 639        }
 640        spin_unlock(&cache_defer_lock);
 641        if (discard)
 642                discard->revisit(discard, 1);
 643}
 644
 645/* Return true if and only if a deferred request is queued. */
 646static bool cache_defer_req(struct cache_req *req, struct cache_head *item)
 647{
 648        struct cache_deferred_req *dreq;
 649
 650        if (req->thread_wait) {
 651                cache_wait_req(req, item);
 652                if (!test_bit(CACHE_PENDING, &item->flags))
 653                        return false;
 654        }
 655        dreq = req->defer(req);
 656        if (dreq == NULL)
 657                return false;
 658        setup_deferral(dreq, item, 1);
 659        if (!test_bit(CACHE_PENDING, &item->flags))
 660                /* Bit could have been cleared before we managed to
 661                 * set up the deferral, so need to revisit just in case
 662                 */
 663                cache_revisit_request(item);
 664
 665        cache_limit_defers();
 666        return true;
 667}
 668
 669static void cache_revisit_request(struct cache_head *item)
 670{
 671        struct cache_deferred_req *dreq;
 672        struct list_head pending;
 673        struct hlist_node *lp, *tmp;
 674        int hash = DFR_HASH(item);
 675
 676        INIT_LIST_HEAD(&pending);
 677        spin_lock(&cache_defer_lock);
 678
 679        hlist_for_each_entry_safe(dreq, lp, tmp, &cache_defer_hash[hash], hash)
 680                if (dreq->item == item) {
 681                        __unhash_deferred_req(dreq);
 682                        list_add(&dreq->recent, &pending);
 683                }
 684
 685        spin_unlock(&cache_defer_lock);
 686
 687        while (!list_empty(&pending)) {
 688                dreq = list_entry(pending.next, struct cache_deferred_req, recent);
 689                list_del_init(&dreq->recent);
 690                dreq->revisit(dreq, 0);
 691        }
 692}
 693
 694void cache_clean_deferred(void *owner)
 695{
 696        struct cache_deferred_req *dreq, *tmp;
 697        struct list_head pending;
 698
 699
 700        INIT_LIST_HEAD(&pending);
 701        spin_lock(&cache_defer_lock);
 702
 703        list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) {
 704                if (dreq->owner == owner) {
 705                        __unhash_deferred_req(dreq);
 706                        list_add(&dreq->recent, &pending);
 707                }
 708        }
 709        spin_unlock(&cache_defer_lock);
 710
 711        while (!list_empty(&pending)) {
 712                dreq = list_entry(pending.next, struct cache_deferred_req, recent);
 713                list_del_init(&dreq->recent);
 714                dreq->revisit(dreq, 1);
 715        }
 716}
 717
 718/*
 719 * communicate with user-space
 720 *
 721 * We have a magic /proc file - /proc/sunrpc/<cachename>/channel.
 722 * On read, you get a full request, or block.
 723 * On write, an update request is processed.
 724 * Poll works if anything to read, and always allows write.
 725 *
 726 * Implemented by linked list of requests.  Each open file has
 727 * a ->private that also exists in this list.  New requests are added
 728 * to the end and may wakeup and preceding readers.
 729 * New readers are added to the head.  If, on read, an item is found with
 730 * CACHE_UPCALLING clear, we free it from the list.
 731 *
 732 */
 733
 734static DEFINE_SPINLOCK(queue_lock);
 735static DEFINE_MUTEX(queue_io_mutex);
 736
 737struct cache_queue {
 738        struct list_head        list;
 739        int                     reader; /* if 0, then request */
 740};
 741struct cache_request {
 742        struct cache_queue      q;
 743        struct cache_head       *item;
 744        char                    * buf;
 745        int                     len;
 746        int                     readers;
 747};
 748struct cache_reader {
 749        struct cache_queue      q;
 750        int                     offset; /* if non-0, we have a refcnt on next request */
 751};
 752
 753static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
 754                          loff_t *ppos, struct cache_detail *cd)
 755{
 756        struct cache_reader *rp = filp->private_data;
 757        struct cache_request *rq;
 758        struct inode *inode = filp->f_path.dentry->d_inode;
 759        int err;
 760
 761        if (count == 0)
 762                return 0;
 763
 764        mutex_lock(&inode->i_mutex); /* protect against multiple concurrent
 765                              * readers on this file */
 766 again:
 767        spin_lock(&queue_lock);
 768        /* need to find next request */
 769        while (rp->q.list.next != &cd->queue &&
 770               list_entry(rp->q.list.next, struct cache_queue, list)
 771               ->reader) {
 772                struct list_head *next = rp->q.list.next;
 773                list_move(&rp->q.list, next);
 774        }
 775        if (rp->q.list.next == &cd->queue) {
 776                spin_unlock(&queue_lock);
 777                mutex_unlock(&inode->i_mutex);
 778                BUG_ON(rp->offset);
 779                return 0;
 780        }
 781        rq = container_of(rp->q.list.next, struct cache_request, q.list);
 782        BUG_ON(rq->q.reader);
 783        if (rp->offset == 0)
 784                rq->readers++;
 785        spin_unlock(&queue_lock);
 786
 787        if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
 788                err = -EAGAIN;
 789                spin_lock(&queue_lock);
 790                list_move(&rp->q.list, &rq->q.list);
 791                spin_unlock(&queue_lock);
 792        } else {
 793                if (rp->offset + count > rq->len)
 794                        count = rq->len - rp->offset;
 795                err = -EFAULT;
 796                if (copy_to_user(buf, rq->buf + rp->offset, count))
 797                        goto out;
 798                rp->offset += count;
 799                if (rp->offset >= rq->len) {
 800                        rp->offset = 0;
 801                        spin_lock(&queue_lock);
 802                        list_move(&rp->q.list, &rq->q.list);
 803                        spin_unlock(&queue_lock);
 804                }
 805                err = 0;
 806        }
 807 out:
 808        if (rp->offset == 0) {
 809                /* need to release rq */
 810                spin_lock(&queue_lock);
 811                rq->readers--;
 812                if (rq->readers == 0 &&
 813                    !test_bit(CACHE_PENDING, &rq->item->flags)) {
 814                        list_del(&rq->q.list);
 815                        spin_unlock(&queue_lock);
 816                        cache_put(rq->item, cd);
 817                        kfree(rq->buf);
 818                        kfree(rq);
 819                } else
 820                        spin_unlock(&queue_lock);
 821        }
 822        if (err == -EAGAIN)
 823                goto again;
 824        mutex_unlock(&inode->i_mutex);
 825        return err ? err :  count;
 826}
 827
 828static ssize_t cache_do_downcall(char *kaddr, const char __user *buf,
 829                                 size_t count, struct cache_detail *cd)
 830{
 831        ssize_t ret;
 832
 833        if (count == 0)
 834                return -EINVAL;
 835        if (copy_from_user(kaddr, buf, count))
 836                return -EFAULT;
 837        kaddr[count] = '\0';
 838        ret = cd->cache_parse(cd, kaddr, count);
 839        if (!ret)
 840                ret = count;
 841        return ret;
 842}
 843
 844static ssize_t cache_slow_downcall(const char __user *buf,
 845                                   size_t count, struct cache_detail *cd)
 846{
 847        static char write_buf[8192]; /* protected by queue_io_mutex */
 848        ssize_t ret = -EINVAL;
 849
 850        if (count >= sizeof(write_buf))
 851                goto out;
 852        mutex_lock(&queue_io_mutex);
 853        ret = cache_do_downcall(write_buf, buf, count, cd);
 854        mutex_unlock(&queue_io_mutex);
 855out:
 856        return ret;
 857}
 858
 859static ssize_t cache_downcall(struct address_space *mapping,
 860                              const char __user *buf,
 861                              size_t count, struct cache_detail *cd)
 862{
 863        struct page *page;
 864        char *kaddr;
 865        ssize_t ret = -ENOMEM;
 866
 867        if (count >= PAGE_CACHE_SIZE)
 868                goto out_slow;
 869
 870        page = find_or_create_page(mapping, 0, GFP_KERNEL);
 871        if (!page)
 872                goto out_slow;
 873
 874        kaddr = kmap(page);
 875        ret = cache_do_downcall(kaddr, buf, count, cd);
 876        kunmap(page);
 877        unlock_page(page);
 878        page_cache_release(page);
 879        return ret;
 880out_slow:
 881        return cache_slow_downcall(buf, count, cd);
 882}
 883
 884static ssize_t cache_write(struct file *filp, const char __user *buf,
 885                           size_t count, loff_t *ppos,
 886                           struct cache_detail *cd)
 887{
 888        struct address_space *mapping = filp->f_mapping;
 889        struct inode *inode = filp->f_path.dentry->d_inode;
 890        ssize_t ret = -EINVAL;
 891
 892        if (!cd->cache_parse)
 893                goto out;
 894
 895        mutex_lock(&inode->i_mutex);
 896        ret = cache_downcall(mapping, buf, count, cd);
 897        mutex_unlock(&inode->i_mutex);
 898out:
 899        return ret;
 900}
 901
 902static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
 903
 904static unsigned int cache_poll(struct file *filp, poll_table *wait,
 905                               struct cache_detail *cd)
 906{
 907        unsigned int mask;
 908        struct cache_reader *rp = filp->private_data;
 909        struct cache_queue *cq;
 910
 911        poll_wait(filp, &queue_wait, wait);
 912
 913        /* alway allow write */
 914        mask = POLL_OUT | POLLWRNORM;
 915
 916        if (!rp)
 917                return mask;
 918
 919        spin_lock(&queue_lock);
 920
 921        for (cq= &rp->q; &cq->list != &cd->queue;
 922             cq = list_entry(cq->list.next, struct cache_queue, list))
 923                if (!cq->reader) {
 924                        mask |= POLLIN | POLLRDNORM;
 925                        break;
 926                }
 927        spin_unlock(&queue_lock);
 928        return mask;
 929}
 930
 931static int cache_ioctl(struct inode *ino, struct file *filp,
 932                       unsigned int cmd, unsigned long arg,
 933                       struct cache_detail *cd)
 934{
 935        int len = 0;
 936        struct cache_reader *rp = filp->private_data;
 937        struct cache_queue *cq;
 938
 939        if (cmd != FIONREAD || !rp)
 940                return -EINVAL;
 941
 942        spin_lock(&queue_lock);
 943
 944        /* only find the length remaining in current request,
 945         * or the length of the next request
 946         */
 947        for (cq= &rp->q; &cq->list != &cd->queue;
 948             cq = list_entry(cq->list.next, struct cache_queue, list))
 949                if (!cq->reader) {
 950                        struct cache_request *cr =
 951                                container_of(cq, struct cache_request, q);
 952                        len = cr->len - rp->offset;
 953                        break;
 954                }
 955        spin_unlock(&queue_lock);
 956
 957        return put_user(len, (int __user *)arg);
 958}
 959
 960static int cache_open(struct inode *inode, struct file *filp,
 961                      struct cache_detail *cd)
 962{
 963        struct cache_reader *rp = NULL;
 964
 965        if (!cd || !try_module_get(cd->owner))
 966                return -EACCES;
 967        nonseekable_open(inode, filp);
 968        if (filp->f_mode & FMODE_READ) {
 969                rp = kmalloc(sizeof(*rp), GFP_KERNEL);
 970                if (!rp)
 971                        return -ENOMEM;
 972                rp->offset = 0;
 973                rp->q.reader = 1;
 974                atomic_inc(&cd->readers);
 975                spin_lock(&queue_lock);
 976                list_add(&rp->q.list, &cd->queue);
 977                spin_unlock(&queue_lock);
 978        }
 979        filp->private_data = rp;
 980        return 0;
 981}
 982
 983static int cache_release(struct inode *inode, struct file *filp,
 984                         struct cache_detail *cd)
 985{
 986        struct cache_reader *rp = filp->private_data;
 987
 988        if (rp) {
 989                spin_lock(&queue_lock);
 990                if (rp->offset) {
 991                        struct cache_queue *cq;
 992                        for (cq= &rp->q; &cq->list != &cd->queue;
 993                             cq = list_entry(cq->list.next, struct cache_queue, list))
 994                                if (!cq->reader) {
 995                                        container_of(cq, struct cache_request, q)
 996                                                ->readers--;
 997                                        break;
 998                                }
 999                        rp->offset = 0;
1000                }
1001                list_del(&rp->q.list);
1002                spin_unlock(&queue_lock);
1003
1004                filp->private_data = NULL;
1005                kfree(rp);
1006
1007                cd->last_close = seconds_since_boot();
1008                atomic_dec(&cd->readers);
1009        }
1010        module_put(cd->owner);
1011        return 0;
1012}
1013
1014
1015
1016static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch)
1017{
1018        struct cache_queue *cq;
1019        spin_lock(&queue_lock);
1020        list_for_each_entry(cq, &detail->queue, list)
1021                if (!cq->reader) {
1022                        struct cache_request *cr = container_of(cq, struct cache_request, q);
1023                        if (cr->item != ch)
1024                                continue;
1025                        if (cr->readers != 0)
1026                                continue;
1027                        list_del(&cr->q.list);
1028                        spin_unlock(&queue_lock);
1029                        cache_put(cr->item, detail);
1030                        kfree(cr->buf);
1031                        kfree(cr);
1032                        return;
1033                }
1034        spin_unlock(&queue_lock);
1035}
1036
1037/*
1038 * Support routines for text-based upcalls.
1039 * Fields are separated by spaces.
1040 * Fields are either mangled to quote space tab newline slosh with slosh
1041 * or a hexified with a leading \x
1042 * Record is terminated with newline.
1043 *
1044 */
1045
1046void qword_add(char **bpp, int *lp, char *str)
1047{
1048        char *bp = *bpp;
1049        int len = *lp;
1050        char c;
1051
1052        if (len < 0) return;
1053
1054        while ((c=*str++) && len)
1055                switch(c) {
1056                case ' ':
1057                case '\t':
1058                case '\n':
1059                case '\\':
1060                        if (len >= 4) {
1061                                *bp++ = '\\';
1062                                *bp++ = '0' + ((c & 0300)>>6);
1063                                *bp++ = '0' + ((c & 0070)>>3);
1064                                *bp++ = '0' + ((c & 0007)>>0);
1065                        }
1066                        len -= 4;
1067                        break;
1068                default:
1069                        *bp++ = c;
1070                        len--;
1071                }
1072        if (c || len <1) len = -1;
1073        else {
1074                *bp++ = ' ';
1075                len--;
1076        }
1077        *bpp = bp;
1078        *lp = len;
1079}
1080EXPORT_SYMBOL_GPL(qword_add);
1081
1082void qword_addhex(char **bpp, int *lp, char *buf, int blen)
1083{
1084        char *bp = *bpp;
1085        int len = *lp;
1086
1087        if (len < 0) return;
1088
1089        if (len > 2) {
1090                *bp++ = '\\';
1091                *bp++ = 'x';
1092                len -= 2;
1093                while (blen && len >= 2) {
1094                        unsigned char c = *buf++;
1095                        *bp++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1);
1096                        *bp++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1);
1097                        len -= 2;
1098                        blen--;
1099                }
1100        }
1101        if (blen || len<1) len = -1;
1102        else {
1103                *bp++ = ' ';
1104                len--;
1105        }
1106        *bpp = bp;
1107        *lp = len;
1108}
1109EXPORT_SYMBOL_GPL(qword_addhex);
1110
1111static void warn_no_listener(struct cache_detail *detail)
1112{
1113        if (detail->last_warn != detail->last_close) {
1114                detail->last_warn = detail->last_close;
1115                if (detail->warn_no_listener)
1116                        detail->warn_no_listener(detail, detail->last_close != 0);
1117        }
1118}
1119
1120static bool cache_listeners_exist(struct cache_detail *detail)
1121{
1122        if (atomic_read(&detail->readers))
1123                return true;
1124        if (detail->last_close == 0)
1125                /* This cache was never opened */
1126                return false;
1127        if (detail->last_close < seconds_since_boot() - 30)
1128                /*
1129                 * We allow for the possibility that someone might
1130                 * restart a userspace daemon without restarting the
1131                 * server; but after 30 seconds, we give up.
1132                 */
1133                 return false;
1134        return true;
1135}
1136
1137/*
1138 * register an upcall request to user-space and queue it up for read() by the
1139 * upcall daemon.
1140 *
1141 * Each request is at most one page long.
1142 */
1143int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h,
1144                void (*cache_request)(struct cache_detail *,
1145                                      struct cache_head *,
1146                                      char **,
1147                                      int *))
1148{
1149
1150        char *buf;
1151        struct cache_request *crq;
1152        char *bp;
1153        int len;
1154
1155        if (!cache_listeners_exist(detail)) {
1156                warn_no_listener(detail);
1157                return -EINVAL;
1158        }
1159
1160        buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1161        if (!buf)
1162                return -EAGAIN;
1163
1164        crq = kmalloc(sizeof (*crq), GFP_KERNEL);
1165        if (!crq) {
1166                kfree(buf);
1167                return -EAGAIN;
1168        }
1169
1170        bp = buf; len = PAGE_SIZE;
1171
1172        cache_request(detail, h, &bp, &len);
1173
1174        if (len < 0) {
1175                kfree(buf);
1176                kfree(crq);
1177                return -EAGAIN;
1178        }
1179        crq->q.reader = 0;
1180        crq->item = cache_get(h);
1181        crq->buf = buf;
1182        crq->len = PAGE_SIZE - len;
1183        crq->readers = 0;
1184        spin_lock(&queue_lock);
1185        list_add_tail(&crq->q.list, &detail->queue);
1186        spin_unlock(&queue_lock);
1187        wake_up(&queue_wait);
1188        return 0;
1189}
1190EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall);
1191
1192/*
1193 * parse a message from user-space and pass it
1194 * to an appropriate cache
1195 * Messages are, like requests, separated into fields by
1196 * spaces and dequotes as \xHEXSTRING or embedded \nnn octal
1197 *
1198 * Message is
1199 *   reply cachename expiry key ... content....
1200 *
1201 * key and content are both parsed by cache
1202 */
1203
1204#define isodigit(c) (isdigit(c) && c <= '7')
1205int qword_get(char **bpp, char *dest, int bufsize)
1206{
1207        /* return bytes copied, or -1 on error */
1208        char *bp = *bpp;
1209        int len = 0;
1210
1211        while (*bp == ' ') bp++;
1212
1213        if (bp[0] == '\\' && bp[1] == 'x') {
1214                /* HEX STRING */
1215                bp += 2;
1216                while (len < bufsize) {
1217                        int h, l;
1218
1219                        h = hex_to_bin(bp[0]);
1220                        if (h < 0)
1221                                break;
1222
1223                        l = hex_to_bin(bp[1]);
1224                        if (l < 0)
1225                                break;
1226
1227                        *dest++ = (h << 4) | l;
1228                        bp += 2;
1229                        len++;
1230                }
1231        } else {
1232                /* text with \nnn octal quoting */
1233                while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) {
1234                        if (*bp == '\\' &&
1235                            isodigit(bp[1]) && (bp[1] <= '3') &&
1236                            isodigit(bp[2]) &&
1237                            isodigit(bp[3])) {
1238                                int byte = (*++bp -'0');
1239                                bp++;
1240                                byte = (byte << 3) | (*bp++ - '0');
1241                                byte = (byte << 3) | (*bp++ - '0');
1242                                *dest++ = byte;
1243                                len++;
1244                        } else {
1245                                *dest++ = *bp++;
1246                                len++;
1247                        }
1248                }
1249        }
1250
1251        if (*bp != ' ' && *bp != '\n' && *bp != '\0')
1252                return -1;
1253        while (*bp == ' ') bp++;
1254        *bpp = bp;
1255        *dest = '\0';
1256        return len;
1257}
1258EXPORT_SYMBOL_GPL(qword_get);
1259
1260
1261/*
1262 * support /proc/sunrpc/cache/$CACHENAME/content
1263 * as a seqfile.
1264 * We call ->cache_show passing NULL for the item to
1265 * get a header, then pass each real item in the cache
1266 */
1267
1268struct handle {
1269        struct cache_detail *cd;
1270};
1271
1272static void *c_start(struct seq_file *m, loff_t *pos)
1273        __acquires(cd->hash_lock)
1274{
1275        loff_t n = *pos;
1276        unsigned int hash, entry;
1277        struct cache_head *ch;
1278        struct cache_detail *cd = ((struct handle*)m->private)->cd;
1279
1280
1281        read_lock(&cd->hash_lock);
1282        if (!n--)
1283                return SEQ_START_TOKEN;
1284        hash = n >> 32;
1285        entry = n & ((1LL<<32) - 1);
1286
1287        for (ch=cd->hash_table[hash]; ch; ch=ch->next)
1288                if (!entry--)
1289                        return ch;
1290        n &= ~((1LL<<32) - 1);
1291        do {
1292                hash++;
1293                n += 1LL<<32;
1294        } while(hash < cd->hash_size &&
1295                cd->hash_table[hash]==NULL);
1296        if (hash >= cd->hash_size)
1297                return NULL;
1298        *pos = n+1;
1299        return cd->hash_table[hash];
1300}
1301
1302static void *c_next(struct seq_file *m, void *p, loff_t *pos)
1303{
1304        struct cache_head *ch = p;
1305        int hash = (*pos >> 32);
1306        struct cache_detail *cd = ((struct handle*)m->private)->cd;
1307
1308        if (p == SEQ_START_TOKEN)
1309                hash = 0;
1310        else if (ch->next == NULL) {
1311                hash++;
1312                *pos += 1LL<<32;
1313        } else {
1314                ++*pos;
1315                return ch->next;
1316        }
1317        *pos &= ~((1LL<<32) - 1);
1318        while (hash < cd->hash_size &&
1319               cd->hash_table[hash] == NULL) {
1320                hash++;
1321                *pos += 1LL<<32;
1322        }
1323        if (hash >= cd->hash_size)
1324                return NULL;
1325        ++*pos;
1326        return cd->hash_table[hash];
1327}
1328
1329static void c_stop(struct seq_file *m, void *p)
1330        __releases(cd->hash_lock)
1331{
1332        struct cache_detail *cd = ((struct handle*)m->private)->cd;
1333        read_unlock(&cd->hash_lock);
1334}
1335
1336static int c_show(struct seq_file *m, void *p)
1337{
1338        struct cache_head *cp = p;
1339        struct cache_detail *cd = ((struct handle*)m->private)->cd;
1340
1341        if (p == SEQ_START_TOKEN)
1342                return cd->cache_show(m, cd, NULL);
1343
1344        ifdebug(CACHE)
1345                seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n",
1346                           convert_to_wallclock(cp->expiry_time),
1347                           atomic_read(&cp->ref.refcount), cp->flags);
1348        cache_get(cp);
1349        if (cache_check(cd, cp, NULL))
1350                /* cache_check does a cache_put on failure */
1351                seq_printf(m, "# ");
1352        else {
1353                if (cache_is_expired(cd, cp))
1354                        seq_printf(m, "# ");
1355                cache_put(cp, cd);
1356        }
1357
1358        return cd->cache_show(m, cd, cp);
1359}
1360
1361static const struct seq_operations cache_content_op = {
1362        .start  = c_start,
1363        .next   = c_next,
1364        .stop   = c_stop,
1365        .show   = c_show,
1366};
1367
1368static int content_open(struct inode *inode, struct file *file,
1369                        struct cache_detail *cd)
1370{
1371        struct handle *han;
1372
1373        if (!cd || !try_module_get(cd->owner))
1374                return -EACCES;
1375        han = __seq_open_private(file, &cache_content_op, sizeof(*han));
1376        if (han == NULL) {
1377                module_put(cd->owner);
1378                return -ENOMEM;
1379        }
1380
1381        han->cd = cd;
1382        return 0;
1383}
1384
1385static int content_release(struct inode *inode, struct file *file,
1386                struct cache_detail *cd)
1387{
1388        int ret = seq_release_private(inode, file);
1389        module_put(cd->owner);
1390        return ret;
1391}
1392
1393static int open_flush(struct inode *inode, struct file *file,
1394                        struct cache_detail *cd)
1395{
1396        if (!cd || !try_module_get(cd->owner))
1397                return -EACCES;
1398        return nonseekable_open(inode, file);
1399}
1400
1401static int release_flush(struct inode *inode, struct file *file,
1402                        struct cache_detail *cd)
1403{
1404        module_put(cd->owner);
1405        return 0;
1406}
1407
1408static ssize_t read_flush(struct file *file, char __user *buf,
1409                          size_t count, loff_t *ppos,
1410                          struct cache_detail *cd)
1411{
1412        char tbuf[22];
1413        unsigned long p = *ppos;
1414        size_t len;
1415
1416        snprintf(tbuf, sizeof(tbuf), "%lu\n", convert_to_wallclock(cd->flush_time));
1417        len = strlen(tbuf);
1418        if (p >= len)
1419                return 0;
1420        len -= p;
1421        if (len > count)
1422                len = count;
1423        if (copy_to_user(buf, (void*)(tbuf+p), len))
1424                return -EFAULT;
1425        *ppos += len;
1426        return len;
1427}
1428
1429static ssize_t write_flush(struct file *file, const char __user *buf,
1430                           size_t count, loff_t *ppos,
1431                           struct cache_detail *cd)
1432{
1433        char tbuf[20];
1434        char *bp, *ep;
1435
1436        if (*ppos || count > sizeof(tbuf)-1)
1437                return -EINVAL;
1438        if (copy_from_user(tbuf, buf, count))
1439                return -EFAULT;
1440        tbuf[count] = 0;
1441        simple_strtoul(tbuf, &ep, 0);
1442        if (*ep && *ep != '\n')
1443                return -EINVAL;
1444
1445        bp = tbuf;
1446        cd->flush_time = get_expiry(&bp);
1447        cd->nextcheck = seconds_since_boot();
1448        cache_flush();
1449
1450        *ppos += count;
1451        return count;
1452}
1453
1454static ssize_t cache_read_procfs(struct file *filp, char __user *buf,
1455                                 size_t count, loff_t *ppos)
1456{
1457        struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
1458
1459        return cache_read(filp, buf, count, ppos, cd);
1460}
1461
1462static ssize_t cache_write_procfs(struct file *filp, const char __user *buf,
1463                                  size_t count, loff_t *ppos)
1464{
1465        struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
1466
1467        return cache_write(filp, buf, count, ppos, cd);
1468}
1469
1470static unsigned int cache_poll_procfs(struct file *filp, poll_table *wait)
1471{
1472        struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
1473
1474        return cache_poll(filp, wait, cd);
1475}
1476
1477static long cache_ioctl_procfs(struct file *filp,
1478                               unsigned int cmd, unsigned long arg)
1479{
1480        struct inode *inode = filp->f_path.dentry->d_inode;
1481        struct cache_detail *cd = PDE(inode)->data;
1482
1483        return cache_ioctl(inode, filp, cmd, arg, cd);
1484}
1485
1486static int cache_open_procfs(struct inode *inode, struct file *filp)
1487{
1488        struct cache_detail *cd = PDE(inode)->data;
1489
1490        return cache_open(inode, filp, cd);
1491}
1492
1493static int cache_release_procfs(struct inode *inode, struct file *filp)
1494{
1495        struct cache_detail *cd = PDE(inode)->data;
1496
1497        return cache_release(inode, filp, cd);
1498}
1499
1500static const struct file_operations cache_file_operations_procfs = {
1501        .owner          = THIS_MODULE,
1502        .llseek         = no_llseek,
1503        .read           = cache_read_procfs,
1504        .write          = cache_write_procfs,
1505        .poll           = cache_poll_procfs,
1506        .unlocked_ioctl = cache_ioctl_procfs, /* for FIONREAD */
1507        .open           = cache_open_procfs,
1508        .release        = cache_release_procfs,
1509};
1510
1511static int content_open_procfs(struct inode *inode, struct file *filp)
1512{
1513        struct cache_detail *cd = PDE(inode)->data;
1514
1515        return content_open(inode, filp, cd);
1516}
1517
1518static int content_release_procfs(struct inode *inode, struct file *filp)
1519{
1520        struct cache_detail *cd = PDE(inode)->data;
1521
1522        return content_release(inode, filp, cd);
1523}
1524
1525static const struct file_operations content_file_operations_procfs = {
1526        .open           = content_open_procfs,
1527        .read           = seq_read,
1528        .llseek         = seq_lseek,
1529        .release        = content_release_procfs,
1530};
1531
1532static int open_flush_procfs(struct inode *inode, struct file *filp)
1533{
1534        struct cache_detail *cd = PDE(inode)->data;
1535
1536        return open_flush(inode, filp, cd);
1537}
1538
1539static int release_flush_procfs(struct inode *inode, struct file *filp)
1540{
1541        struct cache_detail *cd = PDE(inode)->data;
1542
1543        return release_flush(inode, filp, cd);
1544}
1545
1546static ssize_t read_flush_procfs(struct file *filp, char __user *buf,
1547                            size_t count, loff_t *ppos)
1548{
1549        struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
1550
1551        return read_flush(filp, buf, count, ppos, cd);
1552}
1553
1554static ssize_t write_flush_procfs(struct file *filp,
1555                                  const char __user *buf,
1556                                  size_t count, loff_t *ppos)
1557{
1558        struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
1559
1560        return write_flush(filp, buf, count, ppos, cd);
1561}
1562
1563static const struct file_operations cache_flush_operations_procfs = {
1564        .open           = open_flush_procfs,
1565        .read           = read_flush_procfs,
1566        .write          = write_flush_procfs,
1567        .release        = release_flush_procfs,
1568        .llseek         = no_llseek,
1569};
1570
1571static void remove_cache_proc_entries(struct cache_detail *cd, struct net *net)
1572{
1573        struct sunrpc_net *sn;
1574
1575        if (cd->u.procfs.proc_ent == NULL)
1576                return;
1577        if (cd->u.procfs.flush_ent)
1578                remove_proc_entry("flush", cd->u.procfs.proc_ent);
1579        if (cd->u.procfs.channel_ent)
1580                remove_proc_entry("channel", cd->u.procfs.proc_ent);
1581        if (cd->u.procfs.content_ent)
1582                remove_proc_entry("content", cd->u.procfs.proc_ent);
1583        cd->u.procfs.proc_ent = NULL;
1584        sn = net_generic(net, sunrpc_net_id);
1585        remove_proc_entry(cd->name, sn->proc_net_rpc);
1586}
1587
1588#ifdef CONFIG_PROC_FS
1589static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1590{
1591        struct proc_dir_entry *p;
1592        struct sunrpc_net *sn;
1593
1594        sn = net_generic(net, sunrpc_net_id);
1595        cd->u.procfs.proc_ent = proc_mkdir(cd->name, sn->proc_net_rpc);
1596        if (cd->u.procfs.proc_ent == NULL)
1597                goto out_nomem;
1598        cd->u.procfs.channel_ent = NULL;
1599        cd->u.procfs.content_ent = NULL;
1600
1601        p = proc_create_data("flush", S_IFREG|S_IRUSR|S_IWUSR,
1602                             cd->u.procfs.proc_ent,
1603                             &cache_flush_operations_procfs, cd);
1604        cd->u.procfs.flush_ent = p;
1605        if (p == NULL)
1606                goto out_nomem;
1607
1608        if (cd->cache_upcall || cd->cache_parse) {
1609                p = proc_create_data("channel", S_IFREG|S_IRUSR|S_IWUSR,
1610                                     cd->u.procfs.proc_ent,
1611                                     &cache_file_operations_procfs, cd);
1612                cd->u.procfs.channel_ent = p;
1613                if (p == NULL)
1614                        goto out_nomem;
1615        }
1616        if (cd->cache_show) {
1617                p = proc_create_data("content", S_IFREG|S_IRUSR|S_IWUSR,
1618                                cd->u.procfs.proc_ent,
1619                                &content_file_operations_procfs, cd);
1620                cd->u.procfs.content_ent = p;
1621                if (p == NULL)
1622                        goto out_nomem;
1623        }
1624        return 0;
1625out_nomem:
1626        remove_cache_proc_entries(cd, net);
1627        return -ENOMEM;
1628}
1629#else /* CONFIG_PROC_FS */
1630static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1631{
1632        return 0;
1633}
1634#endif
1635
1636void __init cache_initialize(void)
1637{
1638        INIT_DELAYED_WORK_DEFERRABLE(&cache_cleaner, do_cache_clean);
1639}
1640
1641int cache_register_net(struct cache_detail *cd, struct net *net)
1642{
1643        int ret;
1644
1645        sunrpc_init_cache_detail(cd);
1646        ret = create_cache_proc_entries(cd, net);
1647        if (ret)
1648                sunrpc_destroy_cache_detail(cd);
1649        return ret;
1650}
1651EXPORT_SYMBOL_GPL(cache_register_net);
1652
1653void cache_unregister_net(struct cache_detail *cd, struct net *net)
1654{
1655        remove_cache_proc_entries(cd, net);
1656        sunrpc_destroy_cache_detail(cd);
1657}
1658EXPORT_SYMBOL_GPL(cache_unregister_net);
1659
1660struct cache_detail *cache_create_net(struct cache_detail *tmpl, struct net *net)
1661{
1662        struct cache_detail *cd;
1663
1664        cd = kmemdup(tmpl, sizeof(struct cache_detail), GFP_KERNEL);
1665        if (cd == NULL)
1666                return ERR_PTR(-ENOMEM);
1667
1668        cd->hash_table = kzalloc(cd->hash_size * sizeof(struct cache_head *),
1669                                 GFP_KERNEL);
1670        if (cd->hash_table == NULL) {
1671                kfree(cd);
1672                return ERR_PTR(-ENOMEM);
1673        }
1674        cd->net = net;
1675        return cd;
1676}
1677EXPORT_SYMBOL_GPL(cache_create_net);
1678
1679void cache_destroy_net(struct cache_detail *cd, struct net *net)
1680{
1681        kfree(cd->hash_table);
1682        kfree(cd);
1683}
1684EXPORT_SYMBOL_GPL(cache_destroy_net);
1685
1686static ssize_t cache_read_pipefs(struct file *filp, char __user *buf,
1687                                 size_t count, loff_t *ppos)
1688{
1689        struct cache_detail *cd = RPC_I(filp->f_path.dentry->d_inode)->private;
1690
1691        return cache_read(filp, buf, count, ppos, cd);
1692}
1693
1694static ssize_t cache_write_pipefs(struct file *filp, const char __user *buf,
1695                                  size_t count, loff_t *ppos)
1696{
1697        struct cache_detail *cd = RPC_I(filp->f_path.dentry->d_inode)->private;
1698
1699        return cache_write(filp, buf, count, ppos, cd);
1700}
1701
1702static unsigned int cache_poll_pipefs(struct file *filp, poll_table *wait)
1703{
1704        struct cache_detail *cd = RPC_I(filp->f_path.dentry->d_inode)->private;
1705
1706        return cache_poll(filp, wait, cd);
1707}
1708
1709static long cache_ioctl_pipefs(struct file *filp,
1710                              unsigned int cmd, unsigned long arg)
1711{
1712        struct inode *inode = filp->f_dentry->d_inode;
1713        struct cache_detail *cd = RPC_I(inode)->private;
1714
1715        return cache_ioctl(inode, filp, cmd, arg, cd);
1716}
1717
1718static int cache_open_pipefs(struct inode *inode, struct file *filp)
1719{
1720        struct cache_detail *cd = RPC_I(inode)->private;
1721
1722        return cache_open(inode, filp, cd);
1723}
1724
1725static int cache_release_pipefs(struct inode *inode, struct file *filp)
1726{
1727        struct cache_detail *cd = RPC_I(inode)->private;
1728
1729        return cache_release(inode, filp, cd);
1730}
1731
1732const struct file_operations cache_file_operations_pipefs = {
1733        .owner          = THIS_MODULE,
1734        .llseek         = no_llseek,
1735        .read           = cache_read_pipefs,
1736        .write          = cache_write_pipefs,
1737        .poll           = cache_poll_pipefs,
1738        .unlocked_ioctl = cache_ioctl_pipefs, /* for FIONREAD */
1739        .open           = cache_open_pipefs,
1740        .release        = cache_release_pipefs,
1741};
1742
1743static int content_open_pipefs(struct inode *inode, struct file *filp)
1744{
1745        struct cache_detail *cd = RPC_I(inode)->private;
1746
1747        return content_open(inode, filp, cd);
1748}
1749
1750static int content_release_pipefs(struct inode *inode, struct file *filp)
1751{
1752        struct cache_detail *cd = RPC_I(inode)->private;
1753
1754        return content_release(inode, filp, cd);
1755}
1756
1757const struct file_operations content_file_operations_pipefs = {
1758        .open           = content_open_pipefs,
1759        .read           = seq_read,
1760        .llseek         = seq_lseek,
1761        .release        = content_release_pipefs,
1762};
1763
1764static int open_flush_pipefs(struct inode *inode, struct file *filp)
1765{
1766        struct cache_detail *cd = RPC_I(inode)->private;
1767
1768        return open_flush(inode, filp, cd);
1769}
1770
1771static int release_flush_pipefs(struct inode *inode, struct file *filp)
1772{
1773        struct cache_detail *cd = RPC_I(inode)->private;
1774
1775        return release_flush(inode, filp, cd);
1776}
1777
1778static ssize_t read_flush_pipefs(struct file *filp, char __user *buf,
1779                            size_t count, loff_t *ppos)
1780{
1781        struct cache_detail *cd = RPC_I(filp->f_path.dentry->d_inode)->private;
1782
1783        return read_flush(filp, buf, count, ppos, cd);
1784}
1785
1786static ssize_t write_flush_pipefs(struct file *filp,
1787                                  const char __user *buf,
1788                                  size_t count, loff_t *ppos)
1789{
1790        struct cache_detail *cd = RPC_I(filp->f_path.dentry->d_inode)->private;
1791
1792        return write_flush(filp, buf, count, ppos, cd);
1793}
1794
1795const struct file_operations cache_flush_operations_pipefs = {
1796        .open           = open_flush_pipefs,
1797        .read           = read_flush_pipefs,
1798        .write          = write_flush_pipefs,
1799        .release        = release_flush_pipefs,
1800        .llseek         = no_llseek,
1801};
1802
1803int sunrpc_cache_register_pipefs(struct dentry *parent,
1804                                 const char *name, umode_t umode,
1805                                 struct cache_detail *cd)
1806{
1807        struct qstr q;
1808        struct dentry *dir;
1809        int ret = 0;
1810
1811        q.name = name;
1812        q.len = strlen(name);
1813        q.hash = full_name_hash(q.name, q.len);
1814        dir = rpc_create_cache_dir(parent, &q, umode, cd);
1815        if (!IS_ERR(dir))
1816                cd->u.pipefs.dir = dir;
1817        else
1818                ret = PTR_ERR(dir);
1819        return ret;
1820}
1821EXPORT_SYMBOL_GPL(sunrpc_cache_register_pipefs);
1822
1823void sunrpc_cache_unregister_pipefs(struct cache_detail *cd)
1824{
1825        rpc_remove_cache_dir(cd->u.pipefs.dir);
1826        cd->u.pipefs.dir = NULL;
1827}
1828EXPORT_SYMBOL_GPL(sunrpc_cache_unregister_pipefs);
1829
1830
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