David Howells | 955d0091 | 2009-04-03 16:42:38 +0100 | [diff] [blame^] | 1 | /* netfs cookie management |
| 2 | * |
| 3 | * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved. |
| 4 | * Written by David Howells (dhowells@redhat.com) |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public License |
| 8 | * as published by the Free Software Foundation; either version |
| 9 | * 2 of the License, or (at your option) any later version. |
| 10 | */ |
| 11 | |
| 12 | #define FSCACHE_DEBUG_LEVEL COOKIE |
| 13 | #include <linux/module.h> |
| 14 | #include <linux/slab.h> |
| 15 | #include "internal.h" |
| 16 | |
| 17 | struct kmem_cache *fscache_cookie_jar; |
| 18 | |
| 19 | /* |
| 20 | * initialise an cookie jar slab element prior to any use |
| 21 | */ |
| 22 | void fscache_cookie_init_once(void *_cookie) |
| 23 | { |
| 24 | struct fscache_cookie *cookie = _cookie; |
| 25 | |
| 26 | memset(cookie, 0, sizeof(*cookie)); |
| 27 | spin_lock_init(&cookie->lock); |
| 28 | INIT_HLIST_HEAD(&cookie->backing_objects); |
| 29 | } |
| 30 | |
| 31 | /* |
| 32 | * destroy a cookie |
| 33 | */ |
| 34 | void __fscache_cookie_put(struct fscache_cookie *cookie) |
| 35 | { |
| 36 | struct fscache_cookie *parent; |
| 37 | |
| 38 | _enter("%p", cookie); |
| 39 | |
| 40 | for (;;) { |
| 41 | _debug("FREE COOKIE %p", cookie); |
| 42 | parent = cookie->parent; |
| 43 | BUG_ON(!hlist_empty(&cookie->backing_objects)); |
| 44 | kmem_cache_free(fscache_cookie_jar, cookie); |
| 45 | |
| 46 | if (!parent) |
| 47 | break; |
| 48 | |
| 49 | cookie = parent; |
| 50 | BUG_ON(atomic_read(&cookie->usage) <= 0); |
| 51 | if (!atomic_dec_and_test(&cookie->usage)) |
| 52 | break; |
| 53 | } |
| 54 | |
| 55 | _leave(""); |
| 56 | } |