diff options
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/fscache-cache.h | 175 | ||||
| -rw-r--r-- | include/linux/wait.h | 24 |
2 files changed, 113 insertions, 86 deletions
diff --git a/include/linux/fscache-cache.h b/include/linux/fscache-cache.h index 5dfa0aa216b6..a9ff9a36b86d 100644 --- a/include/linux/fscache-cache.h +++ b/include/linux/fscache-cache.h @@ -97,7 +97,8 @@ struct fscache_operation { #define FSCACHE_OP_WAITING 4 /* cleared when op is woken */ #define FSCACHE_OP_EXCLUSIVE 5 /* exclusive op, other ops must wait */ #define FSCACHE_OP_DEC_READ_CNT 6 /* decrement object->n_reads on destruction */ -#define FSCACHE_OP_KEEP_FLAGS 0x0070 /* flags to keep when repurposing an op */ +#define FSCACHE_OP_UNUSE_COOKIE 7 /* call fscache_unuse_cookie() on completion */ +#define FSCACHE_OP_KEEP_FLAGS 0x00f0 /* flags to keep when repurposing an op */ enum fscache_operation_state state; atomic_t usage; @@ -150,7 +151,7 @@ struct fscache_retrieval { void *context; /* netfs read context (pinned) */ struct list_head to_do; /* list of things to be done by the backend */ unsigned long start_time; /* time at which retrieval started */ - unsigned n_pages; /* number of pages to be retrieved */ + atomic_t n_pages; /* number of pages to be retrieved */ }; typedef int (*fscache_page_retrieval_func_t)(struct fscache_retrieval *op, @@ -194,15 +195,14 @@ static inline void fscache_enqueue_retrieval(struct fscache_retrieval *op) static inline void fscache_retrieval_complete(struct fscache_retrieval *op, int n_pages) { - op->n_pages -= n_pages; - if (op->n_pages <= 0) + atomic_sub(n_pages, &op->n_pages); + if (atomic_read(&op->n_pages) <= 0) fscache_op_complete(&op->op, true); } /** * fscache_put_retrieval - Drop a reference to a retrieval operation * @op: The retrieval operation affected - * @n_pages: The number of pages to account for * * Drop a reference to a retrieval operation. */ @@ -314,6 +314,7 @@ struct fscache_cache_ops { struct fscache_cookie { atomic_t usage; /* number of users of this cookie */ atomic_t n_children; /* number of children of this cookie */ + atomic_t n_active; /* number of active users of netfs ptrs */ spinlock_t lock; spinlock_t stores_lock; /* lock on page store tree */ struct hlist_head backing_objects; /* object(s) backing this file/index */ @@ -326,13 +327,11 @@ struct fscache_cookie { unsigned long flags; #define FSCACHE_COOKIE_LOOKING_UP 0 /* T if non-index cookie being looked up still */ -#define FSCACHE_COOKIE_CREATING 1 /* T if non-index object being created still */ -#define FSCACHE_COOKIE_NO_DATA_YET 2 /* T if new object with no cached data yet */ -#define FSCACHE_COOKIE_PENDING_FILL 3 /* T if pending initial fill on object */ -#define FSCACHE_COOKIE_FILLING 4 /* T if filling object incrementally */ -#define FSCACHE_COOKIE_UNAVAILABLE 5 /* T if cookie is unavailable (error, etc) */ -#define FSCACHE_COOKIE_WAITING_ON_READS 6 /* T if cookie is waiting on reads */ -#define FSCACHE_COOKIE_INVALIDATING 7 /* T if cookie is being invalidated */ +#define FSCACHE_COOKIE_NO_DATA_YET 1 /* T if new object with no cached data yet */ +#define FSCACHE_COOKIE_UNAVAILABLE 2 /* T if cookie is unavailable (error, etc) */ +#define FSCACHE_COOKIE_INVALIDATING 3 /* T if cookie is being invalidated */ +#define FSCACHE_COOKIE_RELINQUISHED 4 /* T if cookie has been relinquished */ +#define FSCACHE_COOKIE_RETIRED 5 /* T if cookie was retired */ }; extern struct fscache_cookie fscache_fsdef_index; @@ -341,45 +340,40 @@ extern struct fscache_cookie fscache_fsdef_index; * Event list for fscache_object::{event_mask,events} */ enum { - FSCACHE_OBJECT_EV_REQUEUE, /* T if object should be requeued */ + FSCACHE_OBJECT_EV_NEW_CHILD, /* T if object has a new child */ + FSCACHE_OBJECT_EV_PARENT_READY, /* T if object's parent is ready */ FSCACHE_OBJECT_EV_UPDATE, /* T if object should be updated */ FSCACHE_OBJECT_EV_INVALIDATE, /* T if cache requested object invalidation */ FSCACHE_OBJECT_EV_CLEARED, /* T if accessors all gone */ FSCACHE_OBJECT_EV_ERROR, /* T if fatal error occurred during processing */ - FSCACHE_OBJECT_EV_RELEASE, /* T if netfs requested object release */ - FSCACHE_OBJECT_EV_RETIRE, /* T if netfs requested object retirement */ - FSCACHE_OBJECT_EV_WITHDRAW, /* T if cache requested object withdrawal */ + FSCACHE_OBJECT_EV_KILL, /* T if netfs relinquished or cache withdrew object */ NR_FSCACHE_OBJECT_EVENTS }; #define FSCACHE_OBJECT_EVENTS_MASK ((1UL << NR_FSCACHE_OBJECT_EVENTS) - 1) /* + * States for object state machine. + */ +struct fscache_transition { + unsigned long events; + const struct fscache_state *transit_to; +}; + +struct fscache_state { + char name[24]; + char short_name[8]; + const struct fscache_state *(*work)(struct fscache_object *object, + int event); + const struct fscache_transition transitions[]; +}; + +/* * on-disk cache file or index handle */ struct fscache_object { - enum fscache_object_state { - FSCACHE_OBJECT_INIT, /* object in initial unbound state */ - FSCACHE_OBJECT_LOOKING_UP, /* looking up object */ - FSCACHE_OBJECT_CREATING, /* creating object */ - - /* active states */ - FSCACHE_OBJECT_AVAILABLE, /* cleaning up object after creation */ - FSCACHE_OBJECT_ACTIVE, /* object is usable */ - FSCACHE_OBJECT_INVALIDATING, /* object is invalidating */ - FSCACHE_OBJECT_UPDATING, /* object is updating */ - - /* terminal states */ - FSCACHE_OBJECT_DYING, /* object waiting for accessors to finish */ - FSCACHE_OBJECT_LC_DYING, /* object cleaning up after lookup/create */ - FSCACHE_OBJECT_ABORT_INIT, /* abort the init state */ - FSCACHE_OBJECT_RELEASING, /* releasing object */ - FSCACHE_OBJECT_RECYCLING, /* retiring object */ - FSCACHE_OBJECT_WITHDRAWING, /* withdrawing object */ - FSCACHE_OBJECT_DEAD, /* object is now dead */ - FSCACHE_OBJECT__NSTATES - } state; - + const struct fscache_state *state; /* Object state machine state */ + const struct fscache_transition *oob_table; /* OOB state transition table */ int debug_id; /* debugging ID */ int n_children; /* number of child objects */ int n_ops; /* number of extant ops on object */ @@ -390,6 +384,7 @@ struct fscache_object { spinlock_t lock; /* state and operations lock */ unsigned long lookup_jif; /* time at which lookup started */ + unsigned long oob_event_mask; /* OOB events this object is interested in */ unsigned long event_mask; /* events this object is interested in */ unsigned long events; /* events to be processed by this object * (order is important - using fls) */ @@ -398,6 +393,9 @@ struct fscache_object { #define FSCACHE_OBJECT_LOCK 0 /* T if object is busy being processed */ #define FSCACHE_OBJECT_PENDING_WRITE 1 /* T if object has pending write */ #define FSCACHE_OBJECT_WAITING 2 /* T if object is waiting on its parent */ +#define FSCACHE_OBJECT_IS_LIVE 3 /* T if object is not withdrawn or relinquished */ +#define FSCACHE_OBJECT_IS_LOOKED_UP 4 /* T if object has been looked up */ +#define FSCACHE_OBJECT_IS_AVAILABLE 5 /* T if object has become active */ struct list_head cache_link; /* link in cache->object_list */ struct hlist_node cookie_link; /* link in cookie->backing_objects */ @@ -415,62 +413,40 @@ struct fscache_object { loff_t store_limit_l; /* current storage limit */ }; -extern const char *fscache_object_states[]; +extern void fscache_object_init(struct fscache_object *, struct fscache_cookie *, + struct fscache_cache *); +extern void fscache_object_destroy(struct fscache_object *); -#define fscache_object_is_active(obj) \ - (!test_bit(FSCACHE_IOERROR, &(obj)->cache->flags) && \ - (obj)->state >= FSCACHE_OBJECT_AVAILABLE && \ - (obj)->state < FSCACHE_OBJECT_DYING) +extern void fscache_object_lookup_negative(struct fscache_object *object); +extern void fscache_obtained_object(struct fscache_object *object); -#define fscache_object_is_dead(obj) \ - (test_bit(FSCACHE_IOERROR, &(obj)->cache->flags) && \ - (obj)->state >= FSCACHE_OBJECT_DYING) +static inline bool fscache_object_is_live(struct fscache_object *object) +{ + return test_bit(FSCACHE_OBJECT_IS_LIVE, &object->flags); +} -extern void fscache_object_work_func(struct work_struct *work); +static inline bool fscache_object_is_dying(struct fscache_object *object) +{ + return !fscache_object_is_live(object); +} -/** - * fscache_object_init - Initialise a cache object description - * @object: Object description - * - * Initialise a cache object description to its basic values. - * - * See Documentation/filesystems/caching/backend-api.txt for a complete - * description. - */ -static inline -void fscache_object_init(struct fscache_object *object, - struct fscache_cookie *cookie, - struct fscache_cache *cache) +static inline bool fscache_object_is_available(struct fscache_object *object) { - atomic_inc(&cache->object_count); - - object->state = FSCACHE_OBJECT_INIT; - spin_lock_init(&object->lock); - INIT_LIST_HEAD(&object->cache_link); - INIT_HLIST_NODE(&object->cookie_link); - INIT_WORK(&object->work, fscache_object_work_func); - INIT_LIST_HEAD(&object->dependents); - INIT_LIST_HEAD(&object->dep_link); - INIT_LIST_HEAD(&object->pending_ops); - object->n_children = 0; - object->n_ops = object->n_in_progress = object->n_exclusive = 0; - object->events = object->event_mask = 0; - object->flags = 0; - object->store_limit = 0; - object->store_limit_l = 0; - object->cache = cache; - object->cookie = cookie; - object->parent = NULL; + return test_bit(FSCACHE_OBJECT_IS_AVAILABLE, &object->flags); } -extern void fscache_object_lookup_negative(struct fscache_object *object); -extern void fscache_obtained_object(struct fscache_object *object); +static inline bool fscache_object_is_active(struct fscache_object *object) +{ + return fscache_object_is_available(object) && + fscache_object_is_live(object) && + !test_bit(FSCACHE_IOERROR, &object->cache->flags); +} -#ifdef CONFIG_FSCACHE_OBJECT_LIST -extern void fscache_object_destroy(struct fscache_object *object); -#else -#define fscache_object_destroy(object) do {} while(0) -#endif +static inline bool fscache_object_is_dead(struct fscache_object *object) +{ + return fscache_object_is_dying(object) && + test_bit(FSCACHE_IOERROR, &object->cache->flags); +} /** * fscache_object_destroyed - Note destruction of an object in a cache @@ -531,6 +507,33 @@ static inline void fscache_end_io(struct fscache_retrieval *op, op->end_io_func(page, op->context, error); } +/** + * fscache_use_cookie - Request usage of cookie attached to an object + * @object: Object description + * + * Request usage of the cookie attached to an object. NULL is returned if the + * relinquishment had reduced the cookie usage count to 0. + */ +static inline bool fscache_use_cookie(struct fscache_object *object) +{ + struct fscache_cookie *cookie = object->cookie; + return atomic_inc_not_zero(&cookie->n_active) != 0; +} + +/** + * fscache_unuse_cookie - Cease usage of cookie attached to an object + * @object: Object description + * + * Cease usage of the cookie attached to an object. When the users count + * reaches zero then the cookie relinquishment will be permitted to proceed. + */ +static inline void fscache_unuse_cookie(struct fscache_object *object) +{ + struct fscache_cookie *cookie = object->cookie; + if (atomic_dec_and_test(&cookie->n_active)) + wake_up_atomic_t(&cookie->n_active); +} + /* * out-of-line cache backend functions */ diff --git a/include/linux/wait.h b/include/linux/wait.h index 1133695eb067..f487a4750b7f 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -23,6 +23,7 @@ struct __wait_queue { struct wait_bit_key { void *flags; int bit_nr; +#define WAIT_ATOMIC_T_BIT_NR -1 }; struct wait_bit_queue { @@ -60,6 +61,9 @@ struct task_struct; #define __WAIT_BIT_KEY_INITIALIZER(word, bit) \ { .flags = word, .bit_nr = bit, } +#define __WAIT_ATOMIC_T_KEY_INITIALIZER(p) \ + { .flags = p, .bit_nr = WAIT_ATOMIC_T_BIT_NR, } + extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct lock_class_key *); #define init_waitqueue_head(q) \ @@ -146,8 +150,10 @@ void __wake_up_bit(wait_queue_head_t *, void *, int); int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned); int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned); void wake_up_bit(void *, int); +void wake_up_atomic_t(atomic_t *); int out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned); int out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned); +int out_of_line_wait_on_atomic_t(atomic_t *, int (*)(atomic_t *), unsigned); wait_queue_head_t *bit_waitqueue(void *, int); #define wake_up(x) __wake_up(x, TASK_NORMAL, 1, NULL) @@ -902,5 +908,23 @@ static inline int wait_on_bit_lock(void *word, int bit, return 0; return out_of_line_wait_on_bit_lock(word, bit, action, mode); } + +/** + * wait_on_atomic_t - Wait for an atomic_t to become 0 + * @val: The atomic value being waited on, a kernel virtual address + * @action: the function used to sleep, which may take special actions + * @mode: the task state to sleep in + * + * Wait for an atomic_t to become 0. We abuse the bit-wait waitqueue table for + * the purpose of getting a waitqueue, but we set the key to a bit number + * outside of the target 'word'. + */ +static inline +int wait_on_atomic_t(atomic_t *val, int (*action)(atomic_t *), unsigned mode) +{ + if (atomic_read(val) == 0) + return 0; + return out_of_line_wait_on_atomic_t(val, action, mode); +} #endif |