/* * net/sunrpc/cache.c * * Generic code for various authentication-related caches * used by sunrpc clients and servers. * * Copyright (C) 2002 Neil Brown <neilb@cse.unsw.edu.au> * * Released under terms in GPL version 2. See COPYING. * */ #include <linux/types.h>#include <linux/fs.h>#include <linux/file.h>#include <linux/slab.h>#include <linux/signal.h>#include <linux/sched.h>#include <linux/kmod.h>#include <linux/list.h>#include <linux/module.h>#include <linux/ctype.h>#include <asm/uaccess.h>#include <linux/poll.h>#include <linux/seq_file.h>#include <linux/proc_fs.h>#include <linux/net.h>#include <linux/workqueue.h>#include <linux/mutex.h>#include <linux/pagemap.h>#include <asm/ioctls.h>#include <linux/sunrpc/types.h>#include <linux/sunrpc/cache.h>#include <linux/sunrpc/stats.h>#include <linux/sunrpc/rpc_pipe_fs.h>#include "netns.h" #define RPCDBG_FACILITY RPCDBG_CACHE static bool cache_defer_req(struct cache_req *req, struct cache_head *item);static void cache_revisit_request(struct cache_head *item); static void cache_init(struct cache_head *h){ time_t now = seconds_since_boot(); h->next = NULL; h->flags = 0; kref_init(&h->ref); h->expiry_time = now + CACHE_NEW_EXPIRY; h->last_refresh = now;} struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail, struct cache_head *key, int hash){ struct cache_head **head, **hp; struct cache_head *new = NULL, *freeme = NULL; head = &detail->hash_table[hash]; read_lock(&detail->hash_lock); for (hp=head; *hp != NULL ; hp = &(*hp)->next) { struct cache_head *tmp = *hp; if (detail->match(tmp, key)) { if (cache_is_expired(detail, tmp)) /* This entry is expired, we will discard it. */ break; cache_get(tmp); read_unlock(&detail->hash_lock); return tmp; } } read_unlock(&detail->hash_lock); /* Didn't find anything, insert an empty entry */ new = detail->alloc(); if (!new) return NULL; /* must fully initialise 'new', else * we might get lose if we need to * cache_put it soon. */ cache_init(new); detail->init(new, key); write_lock(&detail->hash_lock); /* check if entry appeared while we slept */ for (hp=head; *hp != NULL ; hp = &(*hp)->next) { struct cache_head *tmp = *hp; if (detail->match(tmp, key)) { if (cache_is_expired(detail, tmp)) { *hp = tmp->next; tmp->next = NULL; detail->entries --; freeme = tmp; break; } cache_get(tmp); write_unlock(&detail->hash_lock); cache_put(new, detail); return tmp; } } new->next = *head; *head = new; detail->entries++; cache_get(new); write_unlock(&detail->hash_lock); if (freeme) cache_put(freeme, detail); return new;}EXPORT_SYMBOL_GPL(sunrpc_cache_lookup); static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch); static void cache_fresh_locked(struct cache_head *head, time_t expiry){ head->expiry_time = expiry; head->last_refresh = seconds_since_boot(); smp_wmb(); /* paired with smp_rmb() in cache_is_valid() */ set_bit(CACHE_VALID, &head->flags);} static void cache_fresh_unlocked(struct cache_head *head, struct cache_detail *detail){ if (test_and_clear_bit(CACHE_PENDING, &head->flags)) { cache_revisit_request(head); cache_dequeue(detail, head); }} struct cache_head *sunrpc_cache_update(struct cache_detail *detail, struct cache_head *new, struct cache_head *old, int hash){ /* The 'old' entry is to be replaced by 'new'. * If 'old' is not VALID, we update it directly, * otherwise we need to replace it */ struct cache_head **head; struct cache_head *tmp; if (!test_bit(CACHE_VALID, &old->flags)) { write_lock(&detail->hash_lock); if (!test_bit(CACHE_VALID, &old->flags)) { if (test_bit(CACHE_NEGATIVE, &new->flags)) set_bit(CACHE_NEGATIVE, &old->flags); else detail->update(old, new); cache_fresh_locked(old, new->expiry_time); write_unlock(&detail->hash_lock); cache_fresh_unlocked(old, detail); return old; } write_unlock(&detail->hash_lock); } /* We need to insert a new entry */ tmp = detail->alloc(); if (!tmp) { cache_put(old, detail); return NULL; } cache_init(tmp); detail->init(tmp, old); head = &detail->hash_table[hash]; write_lock(&detail->hash_lock); if (test_bit(CACHE_NEGATIVE, &new->flags)) set_bit(CACHE_NEGATIVE, &tmp->flags); else detail->update(tmp, new); tmp->next = *head; *head = tmp; detail->entries++; cache_get(tmp); cache_fresh_locked(tmp, new->expiry_time); cache_fresh_locked(old, 0); write_unlock(&detail->hash_lock); cache_fresh_unlocked(tmp, detail); cache_fresh_unlocked(old, detail); cache_put(old, detail); return tmp;}EXPORT_SYMBOL_GPL(sunrpc_cache_update); static int cache_make_upcall(struct cache_detail *cd, struct cache_head *h){ if (cd->cache_upcall) return cd->cache_upcall(cd, h); return sunrpc_cache_pipe_upcall(cd, h);} static inline int cache_is_valid(struct cache_head *h){ if (!test_bit(CACHE_VALID, &h->flags)) return -EAGAIN; else { /* entry is valid */ if (test_bit(CACHE_NEGATIVE, &h->flags)) return -ENOENT; else { /* * In combination with write barrier in * sunrpc_cache_update, ensures that anyone * using the cache entry after this sees the * updated contents: */ smp_rmb(); return 0; } }} static int try_to_negate_entry(struct cache_detail *detail, struct cache_head *h){ int rv; write_lock(&detail->hash_lock); rv = cache_is_valid(h); if (rv == -EAGAIN) { set_bit(CACHE_NEGATIVE, &h->flags); cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY); rv = -ENOENT; } write_unlock(&detail->hash_lock); cache_fresh_unlocked(h, detail); return rv;} /* * This is the generic cache management routine for all * the authentication caches. * It checks the currency of a cache item and will (later) * initiate an upcall to fill it if needed. * * * Returns 0 if the cache_head can be used, or cache_puts it and returns * -EAGAIN if upcall is pending and request has been queued * -ETIMEDOUT if upcall failed or request could not be queue or * upcall completed but item is still invalid (implying that * the cache item has been replaced with a newer one). * -ENOENT if cache entry was negative */int cache_check(struct cache_detail *detail, struct cache_head *h, struct cache_req *rqstp){ int rv; long refresh_age, age; /* First decide return status as best we can */ rv = cache_is_valid(h); /* now see if we want to start an upcall */ refresh_age = (h->expiry_time - h->last_refresh); age = seconds_since_boot() - h->last_refresh; if (rqstp == NULL) { if (rv == -EAGAIN) rv = -ENOENT; } else if (rv == -EAGAIN || (h->expiry_time != 0 && age > refresh_age/2)) { dprintk("RPC: Want update, refage=%ld, age=%ld\n", refresh_age, age); if (!test_and_set_bit(CACHE_PENDING, &h->flags)) { switch (cache_make_upcall(detail, h)) { case -EINVAL: rv = try_to_negate_entry(detail, h); break; case -EAGAIN: cache_fresh_unlocked(h, detail); break; } } } if (rv == -EAGAIN) { if (!cache_defer_req(rqstp, h)) { /* * Request was not deferred; handle it as best * we can ourselves: */ rv = cache_is_valid(h); if (rv == -EAGAIN) rv = -ETIMEDOUT; } } if (rv) cache_put(h, detail); return rv;}EXPORT_SYMBOL_GPL(cache_check); /* * caches need to be periodically cleaned. * For this we maintain a list of cache_detail and * a current pointer into that list and into the table * for that entry. * * Each time cache_clean is called it finds the next non-empty entry * in the current table and walks the list in that entry * looking for entries that can be removed. * * An entry gets removed if: * - The expiry is before current time * - The last_refresh time is before the flush_time for that cache * * later we might drop old entries with non-NEVER expiry if that table * is getting 'full' for some definition of 'full' * * The question of "how often to scan a table" is an interesting one * and is answered in part by the use of the "nextcheck" field in the * cache_detail. * When a scan of a table begins, the nextcheck field is set to a time * that is well into the future. * While scanning, if an expiry time is found that is earlier than the * current nextcheck time, nextcheck is set to that expiry time. * If the flush_time is ever set to a time earlier than the nextcheck * time, the nextcheck time is then set to that flush_time. * * A table is then only scanned if the current time is at least * the nextcheck time. * */ static LIST_HEAD(cache_list);static DEFINE_SPINLOCK(cache_list_lock);static struct cache_detail *current_detail;static int current_index; static void do_cache_clean(struct work_struct *work);static struct delayed_work cache_cleaner; void sunrpc_init_cache_detail(struct cache_detail *cd){ rwlock_init(&cd->hash_lock); INIT_LIST_HEAD(&cd->queue); spin_lock(&cache_list_lock); cd->nextcheck = 0; cd->entries = 0; atomic_set(&cd->readers, 0); cd->last_close = 0; cd->last_warn = -1; list_add(&cd->others, &cache_list); spin_unlock(&cache_list_lock); /* start the cleaning process */ schedule_delayed_work(&cache_cleaner, 0);}EXPORT_SYMBOL_GPL(sunrpc_init_cache_detail); void sunrpc_destroy_cache_detail(struct cache_detail *cd){ cache_purge(cd); spin_lock(&cache_list_lock); write_lock(&cd->hash_lock); if (cd->entries || atomic_read(&cd->inuse)) { write_unlock(&cd->hash_lock); spin_unlock(&cache_list_lock); goto out; } if (current_detail == cd) current_detail = NULL; list_del_init(&cd->others); write_unlock(&cd->hash_lock); spin_unlock(&cache_list_lock); if (list_empty(&cache_list)) { /* module must be being unloaded so its safe to kill the worker */ cancel_delayed_work_sync(&cache_cleaner); } return;out: printk(KERN_ERR "nfsd: failed to unregister %s cache\n", cd->name);}EXPORT_SYMBOL_GPL(sunrpc_destroy_cache_detail); /* clean cache tries to find something to clean * and cleans it. * It returns 1 if it cleaned something, * 0 if it didn't find anything this time * -1 if it fell off the end of the list. */static int cache_clean(void){ int rv = 0; struct list_head *next; spin_lock(&cache_list_lock); /* find a suitable table if we don't already have one */ while (current_detail == NULL || current_index >= current_detail->hash_size) { if (current_detail) next = current_detail->others.next; else next = cache_list.next; if (next == &cache_list) { current_detail = NULL; spin_unlock(&cache_list_lock); return -1; } current_detail = list_entry(next, struct cache_detail, others); if (current_detail->nextcheck > seconds_since_boot()) current_index = current_detail->hash_size; else { current_index = 0; current_detail->nextcheck = seconds_since_boot()+30*60; } } /* find a non-empty bucket in the table */ while (current_detail && current_index < current_detail->hash_size && current_detail->hash_table[current_index] == NULL) current_index++; /* find a cleanable entry in the bucket and clean it, or set to next bucket */ if (current_detail && current_index < current_detail->hash_size) { struct cache_head *ch, **cp; struct cache_detail *d; write_lock(¤t_detail->hash_lock); /* Ok, now to clean this strand */ cp = & current_detail->hash_table[current_index]; for (ch = *cp ; ch ; cp = & ch->next, ch = *cp) { if (current_detail->nextcheck > ch->expiry_time) current_detail->nextcheck = ch->expiry_time+1; if (!cache_is_expired(current_detail, ch)) continue; *cp = ch->next; ch->next = NULL; current_detail->entries--; rv = 1; break; } write_unlock(¤t_detail->hash_lock); d = current_detail; if (!ch) current_index ++; spin_unlock(&cache_list_lock); if (ch) { set_bit(CACHE_CLEANED, &ch->flags); cache_fresh_unlocked(ch, d); cache_put(ch, d); } } else spin_unlock(&cache_list_lock); return rv;} /* * We want to regularly clean the cache, so we need to schedule some work ... */static void do_cache_clean(struct work_struct *work){ int delay = 5; if (cache_clean() == -1) delay = round_jiffies_relative(30*HZ); if (list_empty(&cache_list)) delay = 0; if (delay) schedule_delayed_work(&cache_cleaner, delay);} /* * Clean all caches promptly. This just calls cache_clean * repeatedly until we are sure that every cache has had a chance to * be fully cleaned */void cache_flush(void){ while (cache_clean() != -1) cond_resched(); while (cache_clean() != -1) cond_resched();}EXPORT_SYMBOL_GPL(cache_flush); void cache_purge(struct cache_detail *detail){ detail->flush_time = LONG_MAX; detail->nextcheck = seconds_since_boot(); cache_flush(); detail->flush_time = 1;}EXPORT_SYMBOL_GPL(cache_purge); Lines 1–500 of 1840. Load more
/* * net/sunrpc/cache.c * * Generic code for various authentication-related caches * used by sunrpc clients and servers. * * Copyright (C) 2002 Neil Brown <neilb@cse.unsw.edu.au> * * Released under terms in GPL version 2. See COPYING. * */ #include <linux/types.h> #include <linux/fs.h> #include <linux/file.h> #include <linux/slab.h> #include <linux/signal.h> #include <linux/sched.h> #include <linux/kmod.h> #include <linux/list.h> #include <linux/module.h> #include <linux/ctype.h> #include <asm/uaccess.h> #include <linux/poll.h> #include <linux/seq_file.h> #include <linux/proc_fs.h> #include <linux/net.h> #include <linux/workqueue.h> #include <linux/mutex.h> #include <linux/pagemap.h> #include <asm/ioctls.h> #include <linux/sunrpc/types.h> #include <linux/sunrpc/cache.h> #include <linux/sunrpc/stats.h> #include <linux/sunrpc/rpc_pipe_fs.h> #include "netns.h" #define RPCDBG_FACILITY RPCDBG_CACHE static bool cache_defer_req(struct cache_req *req, struct cache_head *item); static void cache_revisit_request(struct cache_head *item); static void cache_init(struct cache_head *h) { time_t now = seconds_since_boot(); h->next = NULL; h->flags = 0; kref_init(&h->ref); h->expiry_time = now + CACHE_NEW_EXPIRY; h->last_refresh = now; } struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail, struct cache_head *key, int hash) { struct cache_head **head, **hp; struct cache_head *new = NULL, *freeme = NULL; head = &detail->hash_table[hash]; read_lock(&detail->hash_lock); for (hp=head; *hp != NULL ; hp = &(*hp)->next) { struct cache_head *tmp = *hp; if (detail->match(tmp, key)) { if (cache_is_expired(detail, tmp)) /* This entry is expired, we will discard it. */ break; cache_get(tmp); read_unlock(&detail->hash_lock); return tmp; } } read_unlock(&detail->hash_lock); /* Didn't find anything, insert an empty entry */ new = detail->alloc(); if (!new) return NULL; /* must fully initialise 'new', else * we might get lose if we need to * cache_put it soon. */ cache_init(new); detail->init(new, key); write_lock(&detail->hash_lock); /* check if entry appeared while we slept */ for (hp=head; *hp != NULL ; hp = &(*hp)->next) { struct cache_head *tmp = *hp; if (detail->match(tmp, key)) { if (cache_is_expired(detail, tmp)) { *hp = tmp->next; tmp->next = NULL; detail->entries --; freeme = tmp; break; } cache_get(tmp); write_unlock(&detail->hash_lock); cache_put(new, detail); return tmp; } } new->next = *head; *head = new; detail->entries++; cache_get(new); write_unlock(&detail->hash_lock); if (freeme) cache_put(freeme, detail); return new; } EXPORT_SYMBOL_GPL(sunrpc_cache_lookup); static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch); static void cache_fresh_locked(struct cache_head *head, time_t expiry) { head->expiry_time = expiry; head->last_refresh = seconds_since_boot(); smp_wmb(); /* paired with smp_rmb() in cache_is_valid() */ set_bit(CACHE_VALID, &head->flags); } static void cache_fresh_unlocked(struct cache_head *head, struct cache_detail *detail) { if (test_and_clear_bit(CACHE_PENDING, &head->flags)) { cache_revisit_request(head); cache_dequeue(detail, head); } } struct cache_head *sunrpc_cache_update(struct cache_detail *detail, struct cache_head *new, struct cache_head *old, int hash) { /* The 'old' entry is to be replaced by 'new'. * If 'old' is not VALID, we update it directly, * otherwise we need to replace it */ struct cache_head **head; struct cache_head *tmp; if (!test_bit(CACHE_VALID, &old->flags)) { write_lock(&detail->hash_lock); if (!test_bit(CACHE_VALID, &old->flags)) { if (test_bit(CACHE_NEGATIVE, &new->flags)) set_bit(CACHE_NEGATIVE, &old->flags); else detail->update(old, new); cache_fresh_locked(old, new->expiry_time); write_unlock(&detail->hash_lock); cache_fresh_unlocked(old, detail); return old; } write_unlock(&detail->hash_lock); } /* We need to insert a new entry */ tmp = detail->alloc(); if (!tmp) { cache_put(old, detail); return NULL; } cache_init(tmp); detail->init(tmp, old); head = &detail->hash_table[hash]; write_lock(&detail->hash_lock); if (test_bit(CACHE_NEGATIVE, &new->flags)) set_bit(CACHE_NEGATIVE, &tmp->flags); else detail->update(tmp, new); tmp->next = *head; *head = tmp; detail->entries++; cache_get(tmp); cache_fresh_locked(tmp, new->expiry_time); cache_fresh_locked(old, 0); write_unlock(&detail->hash_lock); cache_fresh_unlocked(tmp, detail); cache_fresh_unlocked(old, detail); cache_put(old, detail); return tmp; } EXPORT_SYMBOL_GPL(sunrpc_cache_update); static int cache_make_upcall(struct cache_detail *cd, struct cache_head *h) { if (cd->cache_upcall) return cd->cache_upcall(cd, h); return sunrpc_cache_pipe_upcall(cd, h); } static inline int cache_is_valid(struct cache_head *h) { if (!test_bit(CACHE_VALID, &h->flags)) return -EAGAIN; else { /* entry is valid */ if (test_bit(CACHE_NEGATIVE, &h->flags)) return -ENOENT; else { /* * In combination with write barrier in * sunrpc_cache_update, ensures that anyone * using the cache entry after this sees the * updated contents: */ smp_rmb(); return 0; } } } static int try_to_negate_entry(struct cache_detail *detail, struct cache_head *h) { int rv; write_lock(&detail->hash_lock); rv = cache_is_valid(h); if (rv == -EAGAIN) { set_bit(CACHE_NEGATIVE, &h->flags); cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY); rv = -ENOENT; } write_unlock(&detail->hash_lock); cache_fresh_unlocked(h, detail); return rv; } /* * This is the generic cache management routine for all * the authentication caches. * It checks the currency of a cache item and will (later) * initiate an upcall to fill it if needed. * * * Returns 0 if the cache_head can be used, or cache_puts it and returns * -EAGAIN if upcall is pending and request has been queued * -ETIMEDOUT if upcall failed or request could not be queue or * upcall completed but item is still invalid (implying that * the cache item has been replaced with a newer one). * -ENOENT if cache entry was negative */ int cache_check(struct cache_detail *detail, struct cache_head *h, struct cache_req *rqstp) { int rv; long refresh_age, age; /* First decide return status as best we can */ rv = cache_is_valid(h); /* now see if we want to start an upcall */ refresh_age = (h->expiry_time - h->last_refresh); age = seconds_since_boot() - h->last_refresh; if (rqstp == NULL) { if (rv == -EAGAIN) rv = -ENOENT; } else if (rv == -EAGAIN || (h->expiry_time != 0 && age > refresh_age/2)) { dprintk("RPC: Want update, refage=%ld, age=%ld\n", refresh_age, age); if (!test_and_set_bit(CACHE_PENDING, &h->flags)) { switch (cache_make_upcall(detail, h)) { case -EINVAL: rv = try_to_negate_entry(detail, h); break; case -EAGAIN: cache_fresh_unlocked(h, detail); break; } } } if (rv == -EAGAIN) { if (!cache_defer_req(rqstp, h)) { /* * Request was not deferred; handle it as best * we can ourselves: */ rv = cache_is_valid(h); if (rv == -EAGAIN) rv = -ETIMEDOUT; } } if (rv) cache_put(h, detail); return rv; } EXPORT_SYMBOL_GPL(cache_check); /* * caches need to be periodically cleaned. * For this we maintain a list of cache_detail and * a current pointer into that list and into the table * for that entry. * * Each time cache_clean is called it finds the next non-empty entry * in the current table and walks the list in that entry * looking for entries that can be removed. * * An entry gets removed if: * - The expiry is before current time * - The last_refresh time is before the flush_time for that cache * * later we might drop old entries with non-NEVER expiry if that table * is getting 'full' for some definition of 'full' * * The question of "how often to scan a table" is an interesting one * and is answered in part by the use of the "nextcheck" field in the * cache_detail. * When a scan of a table begins, the nextcheck field is set to a time * that is well into the future. * While scanning, if an expiry time is found that is earlier than the * current nextcheck time, nextcheck is set to that expiry time. * If the flush_time is ever set to a time earlier than the nextcheck * time, the nextcheck time is then set to that flush_time. * * A table is then only scanned if the current time is at least * the nextcheck time. * */ static LIST_HEAD(cache_list); static DEFINE_SPINLOCK(cache_list_lock); static struct cache_detail *current_detail; static int current_index; static void do_cache_clean(struct work_struct *work); static struct delayed_work cache_cleaner; void sunrpc_init_cache_detail(struct cache_detail *cd) { rwlock_init(&cd->hash_lock); INIT_LIST_HEAD(&cd->queue); spin_lock(&cache_list_lock); cd->nextcheck = 0; cd->entries = 0; atomic_set(&cd->readers, 0); cd->last_close = 0; cd->last_warn = -1; list_add(&cd->others, &cache_list); spin_unlock(&cache_list_lock); /* start the cleaning process */ schedule_delayed_work(&cache_cleaner, 0); } EXPORT_SYMBOL_GPL(sunrpc_init_cache_detail); void sunrpc_destroy_cache_detail(struct cache_detail *cd) { cache_purge(cd); spin_lock(&cache_list_lock); write_lock(&cd->hash_lock); if (cd->entries || atomic_read(&cd->inuse)) { write_unlock(&cd->hash_lock); spin_unlock(&cache_list_lock); goto out; } if (current_detail == cd) current_detail = NULL; list_del_init(&cd->others); write_unlock(&cd->hash_lock); spin_unlock(&cache_list_lock); if (list_empty(&cache_list)) { /* module must be being unloaded so its safe to kill the worker */ cancel_delayed_work_sync(&cache_cleaner); } return; out: printk(KERN_ERR "nfsd: failed to unregister %s cache\n", cd->name); } EXPORT_SYMBOL_GPL(sunrpc_destroy_cache_detail); /* clean cache tries to find something to clean * and cleans it. * It returns 1 if it cleaned something, * 0 if it didn't find anything this time * -1 if it fell off the end of the list. */ static int cache_clean(void) { int rv = 0; struct list_head *next; spin_lock(&cache_list_lock); /* find a suitable table if we don't already have one */ while (current_detail == NULL || current_index >= current_detail->hash_size) { if (current_detail) next = current_detail->others.next; else next = cache_list.next; if (next == &cache_list) { current_detail = NULL; spin_unlock(&cache_list_lock); return -1; } current_detail = list_entry(next, struct cache_detail, others); if (current_detail->nextcheck > seconds_since_boot()) current_index = current_detail->hash_size; else { current_index = 0; current_detail->nextcheck = seconds_since_boot()+30*60; } } /* find a non-empty bucket in the table */ while (current_detail && current_index < current_detail->hash_size && current_detail->hash_table[current_index] == NULL) current_index++; /* find a cleanable entry in the bucket and clean it, or set to next bucket */ if (current_detail && current_index < current_detail->hash_size) { struct cache_head *ch, **cp; struct cache_detail *d; write_lock(¤t_detail->hash_lock); /* Ok, now to clean this strand */ cp = & current_detail->hash_table[current_index]; for (ch = *cp ; ch ; cp = & ch->next, ch = *cp) { if (current_detail->nextcheck > ch->expiry_time) current_detail->nextcheck = ch->expiry_time+1; if (!cache_is_expired(current_detail, ch)) continue; *cp = ch->next; ch->next = NULL; current_detail->entries--; rv = 1; break; } write_unlock(¤t_detail->hash_lock); d = current_detail; if (!ch) current_index ++; spin_unlock(&cache_list_lock); if (ch) { set_bit(CACHE_CLEANED, &ch->flags); cache_fresh_unlocked(ch, d); cache_put(ch, d); } } else spin_unlock(&cache_list_lock); return rv; } /* * We want to regularly clean the cache, so we need to schedule some work ... */ static void do_cache_clean(struct work_struct *work) { int delay = 5; if (cache_clean() == -1) delay = round_jiffies_relative(30*HZ); if (list_empty(&cache_list)) delay = 0; if (delay) schedule_delayed_work(&cache_cleaner, delay); } /* * Clean all caches promptly. This just calls cache_clean * repeatedly until we are sure that every cache has had a chance to * be fully cleaned */ void cache_flush(void) { while (cache_clean() != -1) cond_resched(); while (cache_clean() != -1) cond_resched(); } EXPORT_SYMBOL_GPL(cache_flush); void cache_purge(struct cache_detail *detail) { detail->flush_time = LONG_MAX; detail->nextcheck = seconds_since_boot(); cache_flush(); detail->flush_time = 1; } EXPORT_SYMBOL_GPL(cache_purge);