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