net/sunrpc/cache.c

   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
  40 static void cache_defer_req(struct cache_req *req, struct cache_head *item);
  41 static void cache_revisit_request(struct cache_head *item);
  42
  43 static 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
  53 static 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
  59 struct 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 }
 122 EXPORT_SYMBOL_GPL(sunrpc_cache_lookup);
 123
 124
 125 static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch);
 126
 127 static 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         set_bit(CACHE_VALID, &head->flags);
 132 }
 133
 134 static void cache_fresh_unlocked(struct cache_head *head,
 135                                  struct cache_detail *detail)
 136 {
 137         if (test_and_clear_bit(CACHE_PENDING, &head->flags)) {
 138                 cache_revisit_request(head);
 139                 cache_dequeue(detail, head);
 140         }
 141 }
 142
 143 struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
 144                                        struct cache_head *new, struct cache_head *old, int hash)
 145 {
 146         /* The 'old' entry is to be replaced by 'new'.
 147          * If 'old' is not VALID, we update it directly,
 148          * otherwise we need to replace it
 149          */
 150         struct cache_head **head;
 151         struct cache_head *tmp;
 152
 153         if (!test_bit(CACHE_VALID, &old->flags)) {
 154                 write_lock(&detail->hash_lock);
 155                 if (!test_bit(CACHE_VALID, &old->flags)) {
 156                         if (test_bit(CACHE_NEGATIVE, &new->flags))
 157                                 set_bit(CACHE_NEGATIVE, &old->flags);
 158                         else
 159                                 detail->update(old, new);
 160                         cache_fresh_locked(old, new->expiry_time);
 161                         write_unlock(&detail->hash_lock);
 162                         cache_fresh_unlocked(old, detail);
 163                         return old;
 164                 }
 165                 write_unlock(&detail->hash_lock);
 166         }
 167         /* We need to insert a new entry */
 168         tmp = detail->alloc();
 169         if (!tmp) {
 170                 cache_put(old, detail);
 171                 return NULL;
 172         }
 173         cache_init(tmp);
 174         detail->init(tmp, old);
 175         head = &detail->hash_table[hash];
 176
 177         write_lock(&detail->hash_lock);
 178         if (test_bit(CACHE_NEGATIVE, &new->flags))
 179                 set_bit(CACHE_NEGATIVE, &tmp->flags);
 180         else
 181                 detail->update(tmp, new);
 182         tmp->next = *head;
 183         *head = tmp;
 184         detail->entries++;
 185         cache_get(tmp);
 186         cache_fresh_locked(tmp, new->expiry_time);
 187         cache_fresh_locked(old, 0);
 188         write_unlock(&detail->hash_lock);
 189         cache_fresh_unlocked(tmp, detail);
 190         cache_fresh_unlocked(old, detail);
 191         cache_put(old, detail);
 192         return tmp;
 193 }
 194 EXPORT_SYMBOL_GPL(sunrpc_cache_update);
 195
 196 static int cache_make_upcall(struct cache_detail *cd, struct cache_head *h)
 197 {
 198         if (!cd->cache_upcall)
 199                 return -EINVAL;
 200         return cd->cache_upcall(cd, h);
 201 }
 202
 203 static inline int cache_is_valid(struct cache_detail *detail, struct cache_head *h)
 204 {
 205         if (!test_bit(CACHE_VALID, &h->flags))
 206                 return -EAGAIN;
 207         else {
 208                 /* entry is valid */
 209                 if (test_bit(CACHE_NEGATIVE, &h->flags))
 210                         return -ENOENT;
 211                 else
 212                         return 0;
 213         }
 214 }
 215
 216 /*
 217  * This is the generic cache management routine for all
 218  * the authentication caches.
 219  * It checks the currency of a cache item and will (later)
 220  * initiate an upcall to fill it if needed.
 221  *
 222  *
 223  * Returns 0 if the cache_head can be used, or cache_puts it and returns
 224  * -EAGAIN if upcall is pending and request has been queued
 225  * -ETIMEDOUT if upcall failed or request could not be queue or
 226  *           upcall completed but item is still invalid (implying that
 227  *           the cache item has been replaced with a newer one).
 228  * -ENOENT if cache entry was negative
 229  */
 230 int cache_check(struct cache_detail *detail,
 231                     struct cache_head *h, struct cache_req *rqstp)
 232 {
 233         int rv;
 234         long refresh_age, age;
 235
 236         /* First decide return status as best we can */
 237         rv = cache_is_valid(detail, h);
 238
 239         /* now see if we want to start an upcall */
 240         refresh_age = (h->expiry_time - h->last_refresh);
 241         age = seconds_since_boot() - h->last_refresh;
 242
 243         if (rqstp == NULL) {
 244                 if (rv == -EAGAIN)
 245                         rv = -ENOENT;
 246         } else if (rv == -EAGAIN || age > refresh_age/2) {
 247                 dprintk("RPC:       Want update, refage=%ld, age=%ld\n",
 248                                 refresh_age, age);
 249                 if (!test_and_set_bit(CACHE_PENDING, &h->flags)) {
 250                         switch (cache_make_upcall(detail, h)) {
 251                         case -EINVAL:
 252                                 clear_bit(CACHE_PENDING, &h->flags);
 253                                 cache_revisit_request(h);
 254                                 if (rv == -EAGAIN) {
 255                                         set_bit(CACHE_NEGATIVE, &h->flags);
 256                                         cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY);
 257                                         cache_fresh_unlocked(h, detail);
 258                                         rv = -ENOENT;
 259                                 }
 260                                 break;
 261
 262                         case -EAGAIN:
 263                                 clear_bit(CACHE_PENDING, &h->flags);
 264                                 cache_revisit_request(h);
 265                                 break;
 266                         }
 267                 }
 268         }
 269
 270         if (rv == -EAGAIN) {
 271                 cache_defer_req(rqstp, h);
 272                 if (!test_bit(CACHE_PENDING, &h->flags)) {
 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 }
 283 EXPORT_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
 317 static LIST_HEAD(cache_list);
 318 static DEFINE_SPINLOCK(cache_list_lock);
 319 static struct cache_detail *current_detail;
 320 static int current_index;
 321
 322 static void do_cache_clean(struct work_struct *work);
 323 static struct delayed_work cache_cleaner;
 324
 325 static 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
 342 static 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;
 362 out:
 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  */
 372 static 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 > seconds_since_boot())
 393                         current_index = current_detail->hash_size;
 394                 else {
 395                         current_index = 0;
 396                         current_detail->nextcheck = seconds_since_boot()+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  */
 450 static 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  */
 469 void cache_flush(void)
 470 {
 471         while (cache_clean() != -1)
 472                 cond_resched();
 473         while (cache_clean() != -1)
 474                 cond_resched();
 475 }
 476 EXPORT_SYMBOL_GPL(cache_flush);
 477
 478 void cache_purge(struct cache_detail *detail)
 479 {
 480         detail->flush_time = LONG_MAX;
 481         detail->nextcheck = seconds_since_boot();
 482         cache_flush();
 483         detail->flush_time = 1;
 484 }
 485 EXPORT_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
 508 static DEFINE_SPINLOCK(cache_defer_lock);
 509 static LIST_HEAD(cache_defer_list);
 510 static struct hlist_head cache_defer_hash[DFR_HASHSIZE];
 511 static int cache_defer_cnt;
 512
 513 static void __unhash_deferred_req(struct cache_deferred_req *dreq)
 514 {
 515         hlist_del_init(&dreq->hash);
 516         if (!list_empty(&dreq->recent)) {
 517                 list_del_init(&dreq->recent);
 518                 cache_defer_cnt--;
 519         }
 520 }
 521
 522 static void __hash_deferred_req(struct cache_deferred_req *dreq, struct cache_head *item)
 523 {
 524         int hash = DFR_HASH(item);
 525
 526         INIT_LIST_HEAD(&dreq->recent);
 527         hlist_add_head(&dreq->hash, &cache_defer_hash[hash]);
 528 }
 529
 530 static void setup_deferral(struct cache_deferred_req *dreq,
 531                            struct cache_head *item,
 532                            int count_me)
 533 {
 534
 535         dreq->item = item;
 536
 537         spin_lock(&cache_defer_lock);
 538
 539         __hash_deferred_req(dreq, item);
 540
 541         if (count_me) {
 542                 cache_defer_cnt++;
 543                 list_add(&dreq->recent, &cache_defer_list);
 544         }
 545
 546         spin_unlock(&cache_defer_lock);
 547
 548 }
 549
 550 struct thread_deferred_req {
 551         struct cache_deferred_req handle;
 552         struct completion completion;
 553 };
 554
 555 static void cache_restart_thread(struct cache_deferred_req *dreq, int too_many)
 556 {
 557         struct thread_deferred_req *dr =
 558                 container_of(dreq, struct thread_deferred_req, handle);
 559         complete(&dr->completion);
 560 }
 561
 562 static void cache_wait_req(struct cache_req *req, struct cache_head *item)
 563 {
 564         struct thread_deferred_req sleeper;
 565         struct cache_deferred_req *dreq = &sleeper.handle;
 566
 567         sleeper.completion = COMPLETION_INITIALIZER_ONSTACK(sleeper.completion);
 568         dreq->revisit = cache_restart_thread;
 569
 570         setup_deferral(dreq, item, 0);
 571
 572         if (!test_bit(CACHE_PENDING, &item->flags) ||
 573             wait_for_completion_interruptible_timeout(
 574                     &sleeper.completion, req->thread_wait) <= 0) {
 575                 /* The completion wasn't completed, so we need
 576                  * to clean up
 577                  */
 578                 spin_lock(&cache_defer_lock);
 579                 if (!hlist_unhashed(&sleeper.handle.hash)) {
 580                         __unhash_deferred_req(&sleeper.handle);
 581                         spin_unlock(&cache_defer_lock);
 582                 } else {
 583                         /* cache_revisit_request already removed
 584                          * this from the hash table, but hasn't
 585                          * called ->revisit yet.  It will very soon
 586                          * and we need to wait for it.
 587                          */
 588                         spin_unlock(&cache_defer_lock);
 589                         wait_for_completion(&sleeper.completion);
 590                 }
 591         }
 592 }
 593
 594 static void cache_limit_defers(void)
 595 {
 596         /* Make sure we haven't exceed the limit of allowed deferred
 597          * requests.
 598          */
 599         struct cache_deferred_req *discard = NULL;
 600
 601         if (cache_defer_cnt <= DFR_MAX)
 602                 return;
 603
 604         spin_lock(&cache_defer_lock);
 605
 606         /* Consider removing either the first or the last */
 607         if (cache_defer_cnt > DFR_MAX) {
 608                 if (net_random() & 1)
 609                         discard = list_entry(cache_defer_list.next,
 610                                              struct cache_deferred_req, recent);
 611                 else
 612                         discard = list_entry(cache_defer_list.prev,
 613                                              struct cache_deferred_req, recent);
 614                 __unhash_deferred_req(discard);
 615         }
 616         spin_unlock(&cache_defer_lock);
 617         if (discard)
 618                 discard->revisit(discard, 1);
 619 }
 620
 621 static void cache_defer_req(struct cache_req *req, struct cache_head *item)
 622 {
 623         struct cache_deferred_req *dreq;
 624
 625         if (req->thread_wait) {
 626                 cache_wait_req(req, item);
 627                 if (!test_bit(CACHE_PENDING, &item->flags))
 628                         return;
 629         }
 630         dreq = req->defer(req);
 631         if (dreq == NULL)
 632                 return;
 633         setup_deferral(dreq, item, 1);
 634         if (!test_bit(CACHE_PENDING, &item->flags))
 635                 /* Bit could have been cleared before we managed to
 636                  * set up the deferral, so need to revisit just in case
 637                  */
 638                 cache_revisit_request(item);
 639
 640         cache_limit_defers();
 641 }
 642
 643 static void cache_revisit_request(struct cache_head *item)
 644 {
 645         struct cache_deferred_req *dreq;
 646         struct list_head pending;
 647         struct hlist_node *lp, *tmp;
 648         int hash = DFR_HASH(item);
 649
 650         INIT_LIST_HEAD(&pending);
 651         spin_lock(&cache_defer_lock);
 652
 653         hlist_for_each_entry_safe(dreq, lp, tmp, &cache_defer_hash[hash], hash)
 654                 if (dreq->item == item) {
 655                         __unhash_deferred_req(dreq);
 656                         list_add(&dreq->recent, &pending);
 657                 }
 658
 659         spin_unlock(&cache_defer_lock);
 660
 661         while (!list_empty(&pending)) {
 662                 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
 663                 list_del_init(&dreq->recent);
 664                 dreq->revisit(dreq, 0);
 665         }
 666 }
 667
 668 void cache_clean_deferred(void *owner)
 669 {
 670         struct cache_deferred_req *dreq, *tmp;
 671         struct list_head pending;
 672
 673
 674         INIT_LIST_HEAD(&pending);
 675         spin_lock(&cache_defer_lock);
 676
 677         list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) {
 678                 if (dreq->owner == owner) {
 679                         __unhash_deferred_req(dreq);
 680                         list_add(&dreq->recent, &pending);
 681                 }
 682         }
 683         spin_unlock(&cache_defer_lock);
 684
 685         while (!list_empty(&pending)) {
 686                 dreq = list_entry(pending.next, struct cache_deferred_req, recent);
 687                 list_del_init(&dreq->recent);
 688                 dreq->revisit(dreq, 1);
 689         }
 690 }
 691
 692 /*
 693  * communicate with user-space
 694  *
 695  * We have a magic /proc file - /proc/sunrpc/<cachename>/channel.
 696  * On read, you get a full request, or block.
 697  * On write, an update request is processed.
 698  * Poll works if anything to read, and always allows write.
 699  *
 700  * Implemented by linked list of requests.  Each open file has
 701  * a ->private that also exists in this list.  New requests are added
 702  * to the end and may wakeup and preceding readers.
 703  * New readers are added to the head.  If, on read, an item is found with
 704  * CACHE_UPCALLING clear, we free it from the list.
 705  *
 706  */
 707
 708 static DEFINE_SPINLOCK(queue_lock);
 709 static DEFINE_MUTEX(queue_io_mutex);
 710
 711 struct cache_queue {
 712         struct list_head        list;
 713         int                     reader; /* if 0, then request */
 714 };
 715 struct cache_request {
 716         struct cache_queue      q;
 717         struct cache_head       *item;
 718         char                    * buf;
 719         int                     len;
 720         int                     readers;
 721 };
 722 struct cache_reader {
 723         struct cache_queue      q;
 724         int                     offset; /* if non-0, we have a refcnt on next request */
 725 };
 726
 727 static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
 728                           loff_t *ppos, struct cache_detail *cd)
 729 {
 730         struct cache_reader *rp = filp->private_data;
 731         struct cache_request *rq;
 732         struct inode *inode = filp->f_path.dentry->d_inode;
 733         int err;
 734
 735         if (count == 0)
 736                 return 0;
 737
 738         mutex_lock(&inode->i_mutex); /* protect against multiple concurrent
 739                               * readers on this file */
 740  again:
 741         spin_lock(&queue_lock);
 742         /* need to find next request */
 743         while (rp->q.list.next != &cd->queue &&
 744                list_entry(rp->q.list.next, struct cache_queue, list)
 745                ->reader) {
 746                 struct list_head *next = rp->q.list.next;
 747                 list_move(&rp->q.list, next);
 748         }
 749         if (rp->q.list.next == &cd->queue) {
 750                 spin_unlock(&queue_lock);
 751                 mutex_unlock(&inode->i_mutex);
 752                 BUG_ON(rp->offset);
 753                 return 0;
 754         }
 755         rq = container_of(rp->q.list.next, struct cache_request, q.list);
 756         BUG_ON(rq->q.reader);
 757         if (rp->offset == 0)
 758                 rq->readers++;
 759         spin_unlock(&queue_lock);
 760
 761         if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
 762                 err = -EAGAIN;
 763                 spin_lock(&queue_lock);
 764                 list_move(&rp->q.list, &rq->q.list);
 765                 spin_unlock(&queue_lock);
 766         } else {
 767                 if (rp->offset + count > rq->len)
 768                         count = rq->len - rp->offset;
 769                 err = -EFAULT;
 770                 if (copy_to_user(buf, rq->buf + rp->offset, count))
 771                         goto out;
 772                 rp->offset += count;
 773                 if (rp->offset >= rq->len) {
 774                         rp->offset = 0;
 775                         spin_lock(&queue_lock);
 776                         list_move(&rp->q.list, &rq->q.list);
 777                         spin_unlock(&queue_lock);
 778                 }
 779                 err = 0;
 780         }
 781  out:
 782         if (rp->offset == 0) {
 783                 /* need to release rq */
 784                 spin_lock(&queue_lock);
 785                 rq->readers--;
 786                 if (rq->readers == 0 &&
 787                     !test_bit(CACHE_PENDING, &rq->item->flags)) {
 788                         list_del(&rq->q.list);
 789                         spin_unlock(&queue_lock);
 790                         cache_put(rq->item, cd);
 791                         kfree(rq->buf);
 792                         kfree(rq);
 793                 } else
 794                         spin_unlock(&queue_lock);
 795         }
 796         if (err == -EAGAIN)
 797                 goto again;
 798         mutex_unlock(&inode->i_mutex);
 799         return err ? err :  count;
 800 }
 801
 802 static ssize_t cache_do_downcall(char *kaddr, const char __user *buf,
 803                                  size_t count, struct cache_detail *cd)
 804 {
 805         ssize_t ret;
 806
 807         if (copy_from_user(kaddr, buf, count))
 808                 return -EFAULT;
 809         kaddr[count] = '\0';
 810         ret = cd->cache_parse(cd, kaddr, count);
 811         if (!ret)
 812                 ret = count;
 813         return ret;
 814 }
 815
 816 static ssize_t cache_slow_downcall(const char __user *buf,
 817                                    size_t count, struct cache_detail *cd)
 818 {
 819         static char write_buf[8192]; /* protected by queue_io_mutex */
 820         ssize_t ret = -EINVAL;
 821
 822         if (count >= sizeof(write_buf))
 823                 goto out;
 824         mutex_lock(&queue_io_mutex);
 825         ret = cache_do_downcall(write_buf, buf, count, cd);
 826         mutex_unlock(&queue_io_mutex);
 827 out:
 828         return ret;
 829 }
 830
 831 static ssize_t cache_downcall(struct address_space *mapping,
 832                               const char __user *buf,
 833                               size_t count, struct cache_detail *cd)
 834 {
 835         struct page *page;
 836         char *kaddr;
 837         ssize_t ret = -ENOMEM;
 838
 839         if (count >= PAGE_CACHE_SIZE)
 840                 goto out_slow;
 841
 842         page = find_or_create_page(mapping, 0, GFP_KERNEL);
 843         if (!page)
 844                 goto out_slow;
 845
 846         kaddr = kmap(page);
 847         ret = cache_do_downcall(kaddr, buf, count, cd);
 848         kunmap(page);
 849         unlock_page(page);
 850         page_cache_release(page);
 851         return ret;
 852 out_slow:
 853         return cache_slow_downcall(buf, count, cd);
 854 }
 855
 856 static ssize_t cache_write(struct file *filp, const char __user *buf,
 857                            size_t count, loff_t *ppos,
 858                            struct cache_detail *cd)
 859 {
 860         struct address_space *mapping = filp->f_mapping;
 861         struct inode *inode = filp->f_path.dentry->d_inode;
 862         ssize_t ret = -EINVAL;
 863
 864         if (!cd->cache_parse)
 865                 goto out;
 866
 867         mutex_lock(&inode->i_mutex);
 868         ret = cache_downcall(mapping, buf, count, cd);
 869         mutex_unlock(&inode->i_mutex);
 870 out:
 871         return ret;
 872 }
 873
 874 static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
 875
 876 static unsigned int cache_poll(struct file *filp, poll_table *wait,
 877                                struct cache_detail *cd)
 878 {
 879         unsigned int mask;
 880         struct cache_reader *rp = filp->private_data;
 881         struct cache_queue *cq;
 882
 883         poll_wait(filp, &queue_wait, wait);
 884
 885         /* alway allow write */
 886         mask = POLL_OUT | POLLWRNORM;
 887
 888         if (!rp)
 889                 return mask;
 890
 891         spin_lock(&queue_lock);
 892
 893         for (cq= &rp->q; &cq->list != &cd->queue;
 894              cq = list_entry(cq->list.next, struct cache_queue, list))
 895                 if (!cq->reader) {
 896                         mask |= POLLIN | POLLRDNORM;
 897                         break;
 898                 }
 899         spin_unlock(&queue_lock);
 900         return mask;
 901 }
 902
 903 static int cache_ioctl(struct inode *ino, struct file *filp,
 904                        unsigned int cmd, unsigned long arg,
 905                        struct cache_detail *cd)
 906 {
 907         int len = 0;
 908         struct cache_reader *rp = filp->private_data;
 909         struct cache_queue *cq;
 910
 911         if (cmd != FIONREAD || !rp)
 912                 return -EINVAL;
 913
 914         spin_lock(&queue_lock);
 915
 916         /* only find the length remaining in current request,
 917          * or the length of the next request
 918          */
 919         for (cq= &rp->q; &cq->list != &cd->queue;
 920              cq = list_entry(cq->list.next, struct cache_queue, list))
 921                 if (!cq->reader) {
 922                         struct cache_request *cr =
 923                                 container_of(cq, struct cache_request, q);
 924                         len = cr->len - rp->offset;
 925                         break;
 926                 }
 927         spin_unlock(&queue_lock);
 928
 929         return put_user(len, (int __user *)arg);
 930 }
 931
 932 static int cache_open(struct inode *inode, struct file *filp,
 933                       struct cache_detail *cd)
 934 {
 935         struct cache_reader *rp = NULL;
 936
 937         if (!cd || !try_module_get(cd->owner))
 938                 return -EACCES;
 939         nonseekable_open(inode, filp);
 940         if (filp->f_mode & FMODE_READ) {
 941                 rp = kmalloc(sizeof(*rp), GFP_KERNEL);
 942                 if (!rp)
 943                         return -ENOMEM;
 944                 rp->offset = 0;
 945                 rp->q.reader = 1;
 946                 atomic_inc(&cd->readers);
 947                 spin_lock(&queue_lock);
 948                 list_add(&rp->q.list, &cd->queue);
 949                 spin_unlock(&queue_lock);
 950         }
 951         filp->private_data = rp;
 952         return 0;
 953 }
 954
 955 static int cache_release(struct inode *inode, struct file *filp,
 956                          struct cache_detail *cd)
 957 {
 958         struct cache_reader *rp = filp->private_data;
 959
 960         if (rp) {
 961                 spin_lock(&queue_lock);
 962                 if (rp->offset) {
 963                         struct cache_queue *cq;
 964                         for (cq= &rp->q; &cq->list != &cd->queue;
 965                              cq = list_entry(cq->list.next, struct cache_queue, list))
 966                                 if (!cq->reader) {
 967                                         container_of(cq, struct cache_request, q)
 968                                                 ->readers--;
 969                                         break;
 970                                 }
 971                         rp->offset = 0;
 972                 }
 973                 list_del(&rp->q.list);
 974                 spin_unlock(&queue_lock);
 975
 976                 filp->private_data = NULL;
 977                 kfree(rp);
 978
 979                 cd->last_close = seconds_since_boot();
 980                 atomic_dec(&cd->readers);
 981         }
 982         module_put(cd->owner);
 983         return 0;
 984 }
 985
 986
 987
 988 static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch)
 989 {
 990         struct cache_queue *cq;
 991         spin_lock(&queue_lock);
 992         list_for_each_entry(cq, &detail->queue, list)
 993                 if (!cq->reader) {
 994                         struct cache_request *cr = container_of(cq, struct cache_request, q);
 995                         if (cr->item != ch)
 996                                 continue;
 997                         if (cr->readers != 0)
 998                                 continue;
 999                         list_del(&cr->q.list);
1000                         spin_unlock(&queue_lock);
1001                         cache_put(cr->item, detail);
1002                         kfree(cr->buf);
1003                         kfree(cr);
1004                         return;
1005                 }
1006         spin_unlock(&queue_lock);
1007 }
1008
1009 /*
1010  * Support routines for text-based upcalls.
1011  * Fields are separated by spaces.
1012  * Fields are either mangled to quote space tab newline slosh with slosh
1013  * or a hexified with a leading \x
1014  * Record is terminated with newline.
1015  *
1016  */
1017
1018 void qword_add(char **bpp, int *lp, char *str)
1019 {
1020         char *bp = *bpp;
1021         int len = *lp;
1022         char c;
1023
1024         if (len < 0) return;
1025
1026         while ((c=*str++) && len)
1027                 switch(c) {
1028                 case ' ':
1029                 case '\t':
1030                 case '\n':
1031                 case '\\':
1032                         if (len >= 4) {
1033                                 *bp++ = '\\';
1034                                 *bp++ = '0' + ((c & 0300)>>6);
1035                                 *bp++ = '0' + ((c & 0070)>>3);
1036                                 *bp++ = '0' + ((c & 0007)>>0);
1037                         }
1038                         len -= 4;
1039                         break;
1040                 default:
1041                         *bp++ = c;
1042                         len--;
1043                 }
1044         if (c || len <1) len = -1;
1045         else {
1046                 *bp++ = ' ';
1047                 len--;
1048         }
1049         *bpp = bp;
1050         *lp = len;
1051 }
1052 EXPORT_SYMBOL_GPL(qword_add);
1053
1054 void qword_addhex(char **bpp, int *lp, char *buf, int blen)
1055 {
1056         char *bp = *bpp;
1057         int len = *lp;
1058
1059         if (len < 0) return;
1060
1061         if (len > 2) {
1062                 *bp++ = '\\';
1063                 *bp++ = 'x';
1064                 len -= 2;
1065                 while (blen && len >= 2) {
1066                         unsigned char c = *buf++;
1067                         *bp++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1);
1068                         *bp++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1);
1069                         len -= 2;
1070                         blen--;
1071                 }
1072         }
1073         if (blen || len<1) len = -1;
1074         else {
1075                 *bp++ = ' ';
1076                 len--;
1077         }
1078         *bpp = bp;
1079         *lp = len;
1080 }
1081 EXPORT_SYMBOL_GPL(qword_addhex);
1082
1083 static void warn_no_listener(struct cache_detail *detail)
1084 {
1085         if (detail->last_warn != detail->last_close) {
1086                 detail->last_warn = detail->last_close;
1087                 if (detail->warn_no_listener)
1088                         detail->warn_no_listener(detail, detail->last_close != 0);
1089         }
1090 }
1091
1092 static bool cache_listeners_exist(struct cache_detail *detail)
1093 {
1094         if (atomic_read(&detail->readers))
1095                 return true;
1096         if (detail->last_close == 0)
1097                 /* This cache was never opened */
1098                 return false;
1099         if (detail->last_close < seconds_since_boot() - 30)
1100                 /*
1101                  * We allow for the possibility that someone might
1102                  * restart a userspace daemon without restarting the
1103                  * server; but after 30 seconds, we give up.
1104                  */
1105                  return false;
1106         return true;
1107 }
1108
1109 /*
1110  * register an upcall request to user-space and queue it up for read() by the
1111  * upcall daemon.
1112  *
1113  * Each request is at most one page long.
1114  */
1115 int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h,
1116                 void (*cache_request)(struct cache_detail *,
1117                                       struct cache_head *,
1118                                       char **,
1119                                       int *))
1120 {
1121
1122         char *buf;
1123         struct cache_request *crq;
1124         char *bp;
1125         int len;
1126
1127         if (!cache_listeners_exist(detail)) {
1128                 warn_no_listener(detail);
1129                 return -EINVAL;
1130         }
1131
1132         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1133         if (!buf)
1134                 return -EAGAIN;
1135
1136         crq = kmalloc(sizeof (*crq), GFP_KERNEL);
1137         if (!crq) {
1138                 kfree(buf);
1139                 return -EAGAIN;
1140         }
1141
1142         bp = buf; len = PAGE_SIZE;
1143
1144         cache_request(detail, h, &bp, &len);
1145
1146         if (len < 0) {
1147                 kfree(buf);
1148                 kfree(crq);
1149                 return -EAGAIN;
1150         }
1151         crq->q.reader = 0;
1152         crq->item = cache_get(h);
1153         crq->buf = buf;
1154         crq->len = PAGE_SIZE - len;
1155         crq->readers = 0;
1156         spin_lock(&queue_lock);
1157         list_add_tail(&crq->q.list, &detail->queue);
1158         spin_unlock(&queue_lock);
1159         wake_up(&queue_wait);
1160         return 0;
1161 }
1162 EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall);
1163
1164 /*
1165  * parse a message from user-space and pass it
1166  * to an appropriate cache
1167  * Messages are, like requests, separated into fields by
1168  * spaces and dequotes as \xHEXSTRING or embedded \nnn octal
1169  *
1170  * Message is
1171  *   reply cachename expiry key ... content....
1172  *
1173  * key and content are both parsed by cache
1174  */
1175
1176 #define isodigit(c) (isdigit(c) && c <= '7')
1177 int qword_get(char **bpp, char *dest, int bufsize)
1178 {
1179         /* return bytes copied, or -1 on error */
1180         char *bp = *bpp;
1181         int len = 0;
1182
1183         while (*bp == ' ') bp++;
1184
1185         if (bp[0] == '\\' && bp[1] == 'x') {
1186                 /* HEX STRING */
1187                 bp += 2;
1188                 while (len < bufsize) {
1189                         int h, l;
1190
1191                         h = hex_to_bin(bp[0]);
1192                         if (h < 0)
1193                                 break;
1194
1195                         l = hex_to_bin(bp[1]);
1196                         if (l < 0)
1197                                 break;
1198
1199                         *dest++ = (h << 4) | l;
1200                         bp += 2;
1201                         len++;
1202                 }
1203         } else {
1204                 /* text with \nnn octal quoting */
1205                 while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) {
1206                         if (*bp == '\\' &&
1207                             isodigit(bp[1]) && (bp[1] <= '3') &&
1208                             isodigit(bp[2]) &&
1209                             isodigit(bp[3])) {
1210                                 int byte = (*++bp -'0');
1211                                 bp++;
1212                                 byte = (byte << 3) | (*bp++ - '0');
1213                                 byte = (byte << 3) | (*bp++ - '0');
1214                                 *dest++ = byte;
1215                                 len++;
1216                         } else {
1217                                 *dest++ = *bp++;
1218                                 len++;
1219                         }
1220                 }
1221         }
1222
1223         if (*bp != ' ' && *bp != '\n' && *bp != '\0')
1224                 return -1;
1225         while (*bp == ' ') bp++;
1226         *bpp = bp;
1227         *dest = '\0';
1228         return len;
1229 }
1230 EXPORT_SYMBOL_GPL(qword_get);
1231
1232
1233 /*
1234  * support /proc/sunrpc/cache/$CACHENAME/content
1235  * as a seqfile.
1236  * We call ->cache_show passing NULL for the item to
1237  * get a header, then pass each real item in the cache
1238  */
1239
1240 struct handle {
1241         struct cache_detail *cd;
1242 };
1243
1244 static void *c_start(struct seq_file *m, loff_t *pos)
1245         __acquires(cd->hash_lock)
1246 {
1247         loff_t n = *pos;
1248         unsigned hash, entry;
1249         struct cache_head *ch;
1250         struct cache_detail *cd = ((struct handle*)m->private)->cd;
1251
1252
1253         read_lock(&cd->hash_lock);
1254         if (!n--)
1255                 return SEQ_START_TOKEN;
1256         hash = n >> 32;
1257         entry = n & ((1LL<<32) - 1);
1258
1259         for (ch=cd->hash_table[hash]; ch; ch=ch->next)
1260                 if (!entry--)
1261                         return ch;
1262         n &= ~((1LL<<32) - 1);
1263         do {
1264                 hash++;
1265                 n += 1LL<<32;
1266         } while(hash < cd->hash_size &&
1267                 cd->hash_table[hash]==NULL);
1268         if (hash >= cd->hash_size)
1269                 return NULL;
1270         *pos = n+1;
1271         return cd->hash_table[hash];
1272 }
1273
1274 static void *c_next(struct seq_file *m, void *p, loff_t *pos)
1275 {
1276         struct cache_head *ch = p;
1277         int hash = (*pos >> 32);
1278         struct cache_detail *cd = ((struct handle*)m->private)->cd;
1279
1280         if (p == SEQ_START_TOKEN)
1281                 hash = 0;
1282         else if (ch->next == NULL) {
1283                 hash++;
1284                 *pos += 1LL<<32;
1285         } else {
1286                 ++*pos;
1287                 return ch->next;
1288         }
1289         *pos &= ~((1LL<<32) - 1);
1290         while (hash < cd->hash_size &&
1291                cd->hash_table[hash] == NULL) {
1292                 hash++;
1293                 *pos += 1LL<<32;
1294         }
1295         if (hash >= cd->hash_size)
1296                 return NULL;
1297         ++*pos;
1298         return cd->hash_table[hash];
1299 }
1300
1301 static void c_stop(struct seq_file *m, void *p)
1302         __releases(cd->hash_lock)
1303 {
1304         struct cache_detail *cd = ((struct handle*)m->private)->cd;
1305         read_unlock(&cd->hash_lock);
1306 }
1307
1308 static int c_show(struct seq_file *m, void *p)
1309 {
1310         struct cache_head *cp = p;
1311         struct cache_detail *cd = ((struct handle*)m->private)->cd;
1312
1313         if (p == SEQ_START_TOKEN)
1314                 return cd->cache_show(m, cd, NULL);
1315
1316         ifdebug(CACHE)
1317                 seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n",
1318                            convert_to_wallclock(cp->expiry_time),
1319                            atomic_read(&cp->ref.refcount), cp->flags);
1320         cache_get(cp);
1321         if (cache_check(cd, cp, NULL))
1322                 /* cache_check does a cache_put on failure */
1323                 seq_printf(m, "# ");
1324         else
1325                 cache_put(cp, cd);
1326
1327         return cd->cache_show(m, cd, cp);
1328 }
1329
1330 static const struct seq_operations cache_content_op = {
1331         .start  = c_start,
1332         .next   = c_next,
1333         .stop   = c_stop,
1334         .show   = c_show,
1335 };
1336
1337 static int content_open(struct inode *inode, struct file *file,
1338                         struct cache_detail *cd)
1339 {
1340         struct handle *han;
1341
1342         if (!cd || !try_module_get(cd->owner))
1343                 return -EACCES;
1344         han = __seq_open_private(file, &cache_content_op, sizeof(*han));
1345         if (han == NULL) {
1346                 module_put(cd->owner);
1347                 return -ENOMEM;
1348         }
1349
1350         han->cd = cd;
1351         return 0;
1352 }
1353
1354 static int content_release(struct inode *inode, struct file *file,
1355                 struct cache_detail *cd)
1356 {
1357         int ret = seq_release_private(inode, file);
1358         module_put(cd->owner);
1359         return ret;
1360 }
1361
1362 static int open_flush(struct inode *inode, struct file *file,
1363                         struct cache_detail *cd)
1364 {
1365         if (!cd || !try_module_get(cd->owner))
1366                 return -EACCES;
1367         return nonseekable_open(inode, file);
1368 }
1369
1370 static int release_flush(struct inode *inode, struct file *file,
1371                         struct cache_detail *cd)
1372 {
1373         module_put(cd->owner);
1374         return 0;
1375 }
1376
1377 static ssize_t read_flush(struct file *file, char __user *buf,
1378                           size_t count, loff_t *ppos,
1379                           struct cache_detail *cd)
1380 {
1381         char tbuf[20];
1382         unsigned long p = *ppos;
1383         size_t len;
1384
1385         sprintf(tbuf, "%lu\n", convert_to_wallclock(cd->flush_time));
1386         len = strlen(tbuf);
1387         if (p >= len)
1388                 return 0;
1389         len -= p;
1390         if (len > count)
1391                 len = count;
1392         if (copy_to_user(buf, (void*)(tbuf+p), len))
1393                 return -EFAULT;
1394         *ppos += len;
1395         return len;
1396 }
1397
1398 static ssize_t write_flush(struct file *file, const char __user *buf,
1399                            size_t count, loff_t *ppos,
1400                            struct cache_detail *cd)
1401 {
1402         char tbuf[20];
1403         char *bp, *ep;
1404
1405         if (*ppos || count > sizeof(tbuf)-1)
1406                 return -EINVAL;
1407         if (copy_from_user(tbuf, buf, count))
1408                 return -EFAULT;
1409         tbuf[count] = 0;
1410         simple_strtoul(tbuf, &ep, 0);
1411         if (*ep && *ep != '\n')
1412                 return -EINVAL;
1413
1414         bp = tbuf;
1415         cd->flush_time = get_expiry(&bp);
1416         cd->nextcheck = seconds_since_boot();
1417         cache_flush();
1418
1419         *ppos += count;
1420         return count;
1421 }
1422
1423 static ssize_t cache_read_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 cache_read(filp, buf, count, ppos, cd);
1429 }
1430
1431 static ssize_t cache_write_procfs(struct file *filp, const char __user *buf,
1432                                   size_t count, loff_t *ppos)
1433 {
1434         struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
1435
1436         return cache_write(filp, buf, count, ppos, cd);
1437 }
1438
1439 static unsigned int cache_poll_procfs(struct file *filp, poll_table *wait)
1440 {
1441         struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
1442
1443         return cache_poll(filp, wait, cd);
1444 }
1445
1446 static long cache_ioctl_procfs(struct file *filp,
1447                                unsigned int cmd, unsigned long arg)
1448 {
1449         struct inode *inode = filp->f_path.dentry->d_inode;
1450         struct cache_detail *cd = PDE(inode)->data;
1451
1452         return cache_ioctl(inode, filp, cmd, arg, cd);
1453 }
1454
1455 static int cache_open_procfs(struct inode *inode, struct file *filp)
1456 {
1457         struct cache_detail *cd = PDE(inode)->data;
1458
1459         return cache_open(inode, filp, cd);
1460 }
1461
1462 static int cache_release_procfs(struct inode *inode, struct file *filp)
1463 {
1464         struct cache_detail *cd = PDE(inode)->data;
1465
1466         return cache_release(inode, filp, cd);
1467 }
1468
1469 static const struct file_operations cache_file_operations_procfs = {
1470         .owner          = THIS_MODULE,
1471         .llseek         = no_llseek,
1472         .read           = cache_read_procfs,
1473         .write          = cache_write_procfs,
1474         .poll           = cache_poll_procfs,
1475         .unlocked_ioctl = cache_ioctl_procfs, /* for FIONREAD */
1476         .open           = cache_open_procfs,
1477         .release        = cache_release_procfs,
1478 };
1479
1480 static int content_open_procfs(struct inode *inode, struct file *filp)
1481 {
1482         struct cache_detail *cd = PDE(inode)->data;
1483
1484         return content_open(inode, filp, cd);
1485 }
1486
1487 static int content_release_procfs(struct inode *inode, struct file *filp)
1488 {
1489         struct cache_detail *cd = PDE(inode)->data;
1490
1491         return content_release(inode, filp, cd);
1492 }
1493
1494 static const struct file_operations content_file_operations_procfs = {
1495         .open           = content_open_procfs,
1496         .read           = seq_read,
1497         .llseek         = seq_lseek,
1498         .release        = content_release_procfs,
1499 };
1500
1501 static int open_flush_procfs(struct inode *inode, struct file *filp)
1502 {
1503         struct cache_detail *cd = PDE(inode)->data;
1504
1505         return open_flush(inode, filp, cd);
1506 }
1507
1508 static int release_flush_procfs(struct inode *inode, struct file *filp)
1509 {
1510         struct cache_detail *cd = PDE(inode)->data;
1511
1512         return release_flush(inode, filp, cd);
1513 }
1514
1515 static ssize_t read_flush_procfs(struct file *filp, char __user *buf,
1516                             size_t count, loff_t *ppos)
1517 {
1518         struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
1519
1520         return read_flush(filp, buf, count, ppos, cd);
1521 }
1522
1523 static ssize_t write_flush_procfs(struct file *filp,
1524                                   const char __user *buf,
1525                                   size_t count, loff_t *ppos)
1526 {
1527         struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data;
1528
1529         return write_flush(filp, buf, count, ppos, cd);
1530 }
1531
1532 static const struct file_operations cache_flush_operations_procfs = {
1533         .open           = open_flush_procfs,
1534         .read           = read_flush_procfs,
1535         .write          = write_flush_procfs,
1536         .release        = release_flush_procfs,
1537         .llseek         = no_llseek,
1538 };
1539
1540 static void remove_cache_proc_entries(struct cache_detail *cd, struct net *net)
1541 {
1542         struct sunrpc_net *sn;
1543
1544         if (cd->u.procfs.proc_ent == NULL)
1545                 return;
1546         if (cd->u.procfs.flush_ent)
1547                 remove_proc_entry("flush", cd->u.procfs.proc_ent);
1548         if (cd->u.procfs.channel_ent)
1549                 remove_proc_entry("channel", cd->u.procfs.proc_ent);
1550         if (cd->u.procfs.content_ent)
1551                 remove_proc_entry("content", cd->u.procfs.proc_ent);
1552         cd->u.procfs.proc_ent = NULL;
1553         sn = net_generic(net, sunrpc_net_id);
1554         remove_proc_entry(cd->name, sn->proc_net_rpc);
1555 }
1556
1557 #ifdef CONFIG_PROC_FS
1558 static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1559 {
1560         struct proc_dir_entry *p;
1561         struct sunrpc_net *sn;
1562
1563         sn = net_generic(net, sunrpc_net_id);
1564         cd->u.procfs.proc_ent = proc_mkdir(cd->name, sn->proc_net_rpc);
1565         if (cd->u.procfs.proc_ent == NULL)
1566                 goto out_nomem;
1567         cd->u.procfs.channel_ent = NULL;
1568         cd->u.procfs.content_ent = NULL;
1569
1570         p = proc_create_data("flush", S_IFREG|S_IRUSR|S_IWUSR,
1571                              cd->u.procfs.proc_ent,
1572                              &cache_flush_operations_procfs, cd);
1573         cd->u.procfs.flush_ent = p;
1574         if (p == NULL)
1575                 goto out_nomem;
1576
1577         if (cd->cache_upcall || cd->cache_parse) {
1578                 p = proc_create_data("channel", S_IFREG|S_IRUSR|S_IWUSR,
1579                                      cd->u.procfs.proc_ent,
1580                                      &cache_file_operations_procfs, cd);
1581                 cd->u.procfs.channel_ent = p;
1582                 if (p == NULL)
1583                         goto out_nomem;
1584         }
1585         if (cd->cache_show) {
1586                 p = proc_create_data("content", S_IFREG|S_IRUSR|S_IWUSR,
1587                                 cd->u.procfs.proc_ent,
1588                                 &content_file_operations_procfs, cd);
1589                 cd->u.procfs.content_ent = p;
1590                 if (p == NULL)
1591                         goto out_nomem;
1592         }
1593         return 0;
1594 out_nomem:
1595         remove_cache_proc_entries(cd, net);
1596         return -ENOMEM;
1597 }
1598 #else /* CONFIG_PROC_FS */
1599 static int create_cache_proc_entries(struct cache_detail *cd, struct net *net)
1600 {
1601         return 0;
1602 }
1603 #endif
1604
1605 void __init cache_initialize(void)
1606 {
1607         INIT_DELAYED_WORK_DEFERRABLE(&cache_cleaner, do_cache_clean);
1608 }
1609
1610 int cache_register_net(struct cache_detail *cd, struct net *net)
1611 {
1612         int ret;
1613
1614         sunrpc_init_cache_detail(cd);
1615         ret = create_cache_proc_entries(cd, net);
1616         if (ret)
1617                 sunrpc_destroy_cache_detail(cd);
1618         return ret;
1619 }
1620
1621 int cache_register(struct cache_detail *cd)
1622 {
1623         return cache_register_net(cd, &init_net);
1624 }
1625 EXPORT_SYMBOL_GPL(cache_register);
1626
1627 void cache_unregister_net(struct cache_detail *cd, struct net *net)
1628 {
1629         remove_cache_proc_entries(cd, net);
1630         sunrpc_destroy_cache_detail(cd);
1631 }
1632
1633 void cache_unregister(struct cache_detail *cd)
1634 {
1635         cache_unregister_net(cd, &init_net);
1636 }
1637 EXPORT_SYMBOL_GPL(cache_unregister);
1638
1639 static ssize_t cache_read_pipefs(struct file *filp, char __user *buf,
1640                                  size_t count, loff_t *ppos)
1641 {
1642         struct cache_detail *cd = RPC_I(filp->f_path.dentry->d_inode)->private;
1643
1644         return cache_read(filp, buf, count, ppos, cd);
1645 }
1646
1647 static ssize_t cache_write_pipefs(struct file *filp, const char __user *buf,
1648                                   size_t count, loff_t *ppos)
1649 {
1650         struct cache_detail *cd = RPC_I(filp->f_path.dentry->d_inode)->private;
1651
1652         return cache_write(filp, buf, count, ppos, cd);
1653 }
1654
1655 static unsigned int cache_poll_pipefs(struct file *filp, poll_table *wait)
1656 {
1657         struct cache_detail *cd = RPC_I(filp->f_path.dentry->d_inode)->private;
1658
1659         return cache_poll(filp, wait, cd);
1660 }
1661
1662 static long cache_ioctl_pipefs(struct file *filp,
1663                               unsigned int cmd, unsigned long arg)
1664 {
1665         struct inode *inode = filp->f_dentry->d_inode;
1666         struct cache_detail *cd = RPC_I(inode)->private;
1667
1668         return cache_ioctl(inode, filp, cmd, arg, cd);
1669 }
1670
1671 static int cache_open_pipefs(struct inode *inode, struct file *filp)
1672 {
1673         struct cache_detail *cd = RPC_I(inode)->private;
1674
1675         return cache_open(inode, filp, cd);
1676 }
1677
1678 static int cache_release_pipefs(struct inode *inode, struct file *filp)
1679 {
1680         struct cache_detail *cd = RPC_I(inode)->private;
1681
1682         return cache_release(inode, filp, cd);
1683 }
1684
1685 const struct file_operations cache_file_operations_pipefs = {
1686         .owner          = THIS_MODULE,
1687         .llseek         = no_llseek,
1688         .read           = cache_read_pipefs,
1689         .write          = cache_write_pipefs,
1690         .poll           = cache_poll_pipefs,
1691         .unlocked_ioctl = cache_ioctl_pipefs, /* for FIONREAD */
1692         .open           = cache_open_pipefs,
1693         .release        = cache_release_pipefs,
1694 };
1695
1696 static int content_open_pipefs(struct inode *inode, struct file *filp)
1697 {
1698         struct cache_detail *cd = RPC_I(inode)->private;
1699
1700         return content_open(inode, filp, cd);
1701 }
1702
1703 static int content_release_pipefs(struct inode *inode, struct file *filp)
1704 {
1705         struct cache_detail *cd = RPC_I(inode)->private;
1706
1707         return content_release(inode, filp, cd);
1708 }
1709
1710 const struct file_operations content_file_operations_pipefs = {
1711         .open           = content_open_pipefs,
1712         .read           = seq_read,
1713         .llseek         = seq_lseek,
1714         .release        = content_release_pipefs,
1715 };
1716
1717 static int open_flush_pipefs(struct inode *inode, struct file *filp)
1718 {
1719         struct cache_detail *cd = RPC_I(inode)->private;
1720
1721         return open_flush(inode, filp, cd);
1722 }
1723
1724 static int release_flush_pipefs(struct inode *inode, struct file *filp)
1725 {
1726         struct cache_detail *cd = RPC_I(inode)->private;
1727
1728         return release_flush(inode, filp, cd);
1729 }
1730
1731 static ssize_t read_flush_pipefs(struct file *filp, char __user *buf,
1732                             size_t count, loff_t *ppos)
1733 {
1734         struct cache_detail *cd = RPC_I(filp->f_path.dentry->d_inode)->private;
1735
1736         return read_flush(filp, buf, count, ppos, cd);
1737 }
1738
1739 static ssize_t write_flush_pipefs(struct file *filp,
1740                                   const char __user *buf,
1741                                   size_t count, loff_t *ppos)
1742 {
1743         struct cache_detail *cd = RPC_I(filp->f_path.dentry->d_inode)->private;
1744
1745         return write_flush(filp, buf, count, ppos, cd);
1746 }
1747
1748 const struct file_operations cache_flush_operations_pipefs = {
1749         .open           = open_flush_pipefs,
1750         .read           = read_flush_pipefs,
1751         .write          = write_flush_pipefs,
1752         .release        = release_flush_pipefs,
1753         .llseek         = no_llseek,
1754 };
1755
1756 int sunrpc_cache_register_pipefs(struct dentry *parent,
1757                                  const char *name, mode_t umode,
1758                                  struct cache_detail *cd)
1759 {
1760         struct qstr q;
1761         struct dentry *dir;
1762         int ret = 0;
1763
1764         sunrpc_init_cache_detail(cd);
1765         q.name = name;
1766         q.len = strlen(name);
1767         q.hash = full_name_hash(q.name, q.len);
1768         dir = rpc_create_cache_dir(parent, &q, umode, cd);
1769         if (!IS_ERR(dir))
1770                 cd->u.pipefs.dir = dir;
1771         else {
1772                 sunrpc_destroy_cache_detail(cd);
1773                 ret = PTR_ERR(dir);
1774         }
1775         return ret;
1776 }
1777 EXPORT_SYMBOL_GPL(sunrpc_cache_register_pipefs);
1778
1779 void sunrpc_cache_unregister_pipefs(struct cache_detail *cd)
1780 {
1781         rpc_remove_cache_dir(cd->u.pipefs.dir);
1782         cd->u.pipefs.dir = NULL;
1783         sunrpc_destroy_cache_detail(cd);
1784 }
1785 EXPORT_SYMBOL_GPL(sunrpc_cache_unregister_pipefs);
1786