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