diff options
Diffstat (limited to 'block/elevator.c')
-rw-r--r-- | block/elevator.c | 217 |
1 files changed, 107 insertions, 110 deletions
diff --git a/block/elevator.c b/block/elevator.c index 66343d6917d0..91e18f8af9be 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -61,8 +61,8 @@ static int elv_iosched_allow_merge(struct request *rq, struct bio *bio) struct request_queue *q = rq->q; struct elevator_queue *e = q->elevator; - if (e->ops->elevator_allow_merge_fn) - return e->ops->elevator_allow_merge_fn(q, rq, bio); + if (e->type->ops.elevator_allow_merge_fn) + return e->type->ops.elevator_allow_merge_fn(q, rq, bio); return 1; } @@ -168,17 +168,13 @@ static struct elevator_type *elevator_get(const char *name) return e; } -static void *elevator_init_queue(struct request_queue *q, - struct elevator_queue *eq) +static int elevator_init_queue(struct request_queue *q, + struct elevator_queue *eq) { - return eq->ops->elevator_init_fn(q); -} - -static void elevator_attach(struct request_queue *q, struct elevator_queue *eq, - void *data) -{ - q->elevator = eq; - eq->elevator_data = data; + eq->elevator_data = eq->type->ops.elevator_init_fn(q); + if (eq->elevator_data) + return 0; + return -ENOMEM; } static char chosen_elevator[ELV_NAME_MAX]; @@ -207,8 +203,7 @@ static struct elevator_queue *elevator_alloc(struct request_queue *q, if (unlikely(!eq)) goto err; - eq->ops = &e->ops; - eq->elevator_type = e; + eq->type = e; kobject_init(&eq->kobj, &elv_ktype); mutex_init(&eq->sysfs_lock); @@ -232,7 +227,7 @@ static void elevator_release(struct kobject *kobj) struct elevator_queue *e; e = container_of(kobj, struct elevator_queue, kobj); - elevator_put(e->elevator_type); + elevator_put(e->type); kfree(e->hash); kfree(e); } @@ -241,7 +236,7 @@ int elevator_init(struct request_queue *q, char *name) { struct elevator_type *e = NULL; struct elevator_queue *eq; - void *data; + int err; if (unlikely(q->elevator)) return 0; @@ -278,13 +273,13 @@ int elevator_init(struct request_queue *q, char *name) if (!eq) return -ENOMEM; - data = elevator_init_queue(q, eq); - if (!data) { + err = elevator_init_queue(q, eq); + if (err) { kobject_put(&eq->kobj); - return -ENOMEM; + return err; } - elevator_attach(q, eq, data); + q->elevator = eq; return 0; } EXPORT_SYMBOL(elevator_init); @@ -292,9 +287,8 @@ EXPORT_SYMBOL(elevator_init); void elevator_exit(struct elevator_queue *e) { mutex_lock(&e->sysfs_lock); - if (e->ops->elevator_exit_fn) - e->ops->elevator_exit_fn(e); - e->ops = NULL; + if (e->type->ops.elevator_exit_fn) + e->type->ops.elevator_exit_fn(e); mutex_unlock(&e->sysfs_lock); kobject_put(&e->kobj); @@ -504,8 +498,8 @@ int elv_merge(struct request_queue *q, struct request **req, struct bio *bio) return ELEVATOR_BACK_MERGE; } - if (e->ops->elevator_merge_fn) - return e->ops->elevator_merge_fn(q, req, bio); + if (e->type->ops.elevator_merge_fn) + return e->type->ops.elevator_merge_fn(q, req, bio); return ELEVATOR_NO_MERGE; } @@ -548,8 +542,8 @@ void elv_merged_request(struct request_queue *q, struct request *rq, int type) { struct elevator_queue *e = q->elevator; - if (e->ops->elevator_merged_fn) - e->ops->elevator_merged_fn(q, rq, type); + if (e->type->ops.elevator_merged_fn) + e->type->ops.elevator_merged_fn(q, rq, type); if (type == ELEVATOR_BACK_MERGE) elv_rqhash_reposition(q, rq); @@ -563,8 +557,8 @@ void elv_merge_requests(struct request_queue *q, struct request *rq, struct elevator_queue *e = q->elevator; const int next_sorted = next->cmd_flags & REQ_SORTED; - if (next_sorted && e->ops->elevator_merge_req_fn) - e->ops->elevator_merge_req_fn(q, rq, next); + if (next_sorted && e->type->ops.elevator_merge_req_fn) + e->type->ops.elevator_merge_req_fn(q, rq, next); elv_rqhash_reposition(q, rq); @@ -581,8 +575,8 @@ void elv_bio_merged(struct request_queue *q, struct request *rq, { struct elevator_queue *e = q->elevator; - if (e->ops->elevator_bio_merged_fn) - e->ops->elevator_bio_merged_fn(q, rq, bio); + if (e->type->ops.elevator_bio_merged_fn) + e->type->ops.elevator_bio_merged_fn(q, rq, bio); } void elv_requeue_request(struct request_queue *q, struct request *rq) @@ -608,12 +602,12 @@ void elv_drain_elevator(struct request_queue *q) lockdep_assert_held(q->queue_lock); - while (q->elevator->ops->elevator_dispatch_fn(q, 1)) + while (q->elevator->type->ops.elevator_dispatch_fn(q, 1)) ; if (q->nr_sorted && printed++ < 10) { printk(KERN_ERR "%s: forced dispatching is broken " "(nr_sorted=%u), please report this\n", - q->elevator->elevator_type->elevator_name, q->nr_sorted); + q->elevator->type->elevator_name, q->nr_sorted); } } @@ -702,7 +696,7 @@ void __elv_add_request(struct request_queue *q, struct request *rq, int where) * rq cannot be accessed after calling * elevator_add_req_fn. */ - q->elevator->ops->elevator_add_req_fn(q, rq); + q->elevator->type->ops.elevator_add_req_fn(q, rq); break; case ELEVATOR_INSERT_FLUSH: @@ -731,8 +725,8 @@ struct request *elv_latter_request(struct request_queue *q, struct request *rq) { struct elevator_queue *e = q->elevator; - if (e->ops->elevator_latter_req_fn) - return e->ops->elevator_latter_req_fn(q, rq); + if (e->type->ops.elevator_latter_req_fn) + return e->type->ops.elevator_latter_req_fn(q, rq); return NULL; } @@ -740,8 +734,8 @@ struct request *elv_former_request(struct request_queue *q, struct request *rq) { struct elevator_queue *e = q->elevator; - if (e->ops->elevator_former_req_fn) - return e->ops->elevator_former_req_fn(q, rq); + if (e->type->ops.elevator_former_req_fn) + return e->type->ops.elevator_former_req_fn(q, rq); return NULL; } @@ -749,10 +743,8 @@ int elv_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask) { struct elevator_queue *e = q->elevator; - if (e->ops->elevator_set_req_fn) - return e->ops->elevator_set_req_fn(q, rq, gfp_mask); - - rq->elevator_private[0] = NULL; + if (e->type->ops.elevator_set_req_fn) + return e->type->ops.elevator_set_req_fn(q, rq, gfp_mask); return 0; } @@ -760,16 +752,16 @@ void elv_put_request(struct request_queue *q, struct request *rq) { struct elevator_queue *e = q->elevator; - if (e->ops->elevator_put_req_fn) - e->ops->elevator_put_req_fn(rq); + if (e->type->ops.elevator_put_req_fn) + e->type->ops.elevator_put_req_fn(rq); } int elv_may_queue(struct request_queue *q, int rw) { struct elevator_queue *e = q->elevator; - if (e->ops->elevator_may_queue_fn) - return e->ops->elevator_may_queue_fn(q, rw); + if (e->type->ops.elevator_may_queue_fn) + return e->type->ops.elevator_may_queue_fn(q, rw); return ELV_MQUEUE_MAY; } @@ -804,8 +796,8 @@ void elv_completed_request(struct request_queue *q, struct request *rq) if (blk_account_rq(rq)) { q->in_flight[rq_is_sync(rq)]--; if ((rq->cmd_flags & REQ_SORTED) && - e->ops->elevator_completed_req_fn) - e->ops->elevator_completed_req_fn(q, rq); + e->type->ops.elevator_completed_req_fn) + e->type->ops.elevator_completed_req_fn(q, rq); } } @@ -823,7 +815,7 @@ elv_attr_show(struct kobject *kobj, struct attribute *attr, char *page) e = container_of(kobj, struct elevator_queue, kobj); mutex_lock(&e->sysfs_lock); - error = e->ops ? entry->show(e, page) : -ENOENT; + error = e->type ? entry->show(e, page) : -ENOENT; mutex_unlock(&e->sysfs_lock); return error; } @@ -841,7 +833,7 @@ elv_attr_store(struct kobject *kobj, struct attribute *attr, e = container_of(kobj, struct elevator_queue, kobj); mutex_lock(&e->sysfs_lock); - error = e->ops ? entry->store(e, page, length) : -ENOENT; + error = e->type ? entry->store(e, page, length) : -ENOENT; mutex_unlock(&e->sysfs_lock); return error; } @@ -856,14 +848,13 @@ static struct kobj_type elv_ktype = { .release = elevator_release, }; -int elv_register_queue(struct request_queue *q) +int __elv_register_queue(struct request_queue *q, struct elevator_queue *e) { - struct elevator_queue *e = q->elevator; int error; error = kobject_add(&e->kobj, &q->kobj, "%s", "iosched"); if (!error) { - struct elv_fs_entry *attr = e->elevator_type->elevator_attrs; + struct elv_fs_entry *attr = e->type->elevator_attrs; if (attr) { while (attr->attr.name) { if (sysfs_create_file(&e->kobj, &attr->attr)) @@ -876,31 +867,55 @@ int elv_register_queue(struct request_queue *q) } return error; } -EXPORT_SYMBOL(elv_register_queue); -static void __elv_unregister_queue(struct elevator_queue *e) +int elv_register_queue(struct request_queue *q) { - kobject_uevent(&e->kobj, KOBJ_REMOVE); - kobject_del(&e->kobj); - e->registered = 0; + return __elv_register_queue(q, q->elevator); } +EXPORT_SYMBOL(elv_register_queue); void elv_unregister_queue(struct request_queue *q) { - if (q) - __elv_unregister_queue(q->elevator); + if (q) { + struct elevator_queue *e = q->elevator; + + kobject_uevent(&e->kobj, KOBJ_REMOVE); + kobject_del(&e->kobj); + e->registered = 0; + } } EXPORT_SYMBOL(elv_unregister_queue); -void elv_register(struct elevator_type *e) +int elv_register(struct elevator_type *e) { char *def = ""; + /* create icq_cache if requested */ + if (e->icq_size) { + if (WARN_ON(e->icq_size < sizeof(struct io_cq)) || + WARN_ON(e->icq_align < __alignof__(struct io_cq))) + return -EINVAL; + + snprintf(e->icq_cache_name, sizeof(e->icq_cache_name), + "%s_io_cq", e->elevator_name); + e->icq_cache = kmem_cache_create(e->icq_cache_name, e->icq_size, + e->icq_align, 0, NULL); + if (!e->icq_cache) + return -ENOMEM; + } + + /* register, don't allow duplicate names */ spin_lock(&elv_list_lock); - BUG_ON(elevator_find(e->elevator_name)); + if (elevator_find(e->elevator_name)) { + spin_unlock(&elv_list_lock); + if (e->icq_cache) + kmem_cache_destroy(e->icq_cache); + return -EBUSY; + } list_add_tail(&e->list, &elv_list); spin_unlock(&elv_list_lock); + /* print pretty message */ if (!strcmp(e->elevator_name, chosen_elevator) || (!*chosen_elevator && !strcmp(e->elevator_name, CONFIG_DEFAULT_IOSCHED))) @@ -908,30 +923,26 @@ void elv_register(struct elevator_type *e) printk(KERN_INFO "io scheduler %s registered%s\n", e->elevator_name, def); + return 0; } EXPORT_SYMBOL_GPL(elv_register); void elv_unregister(struct elevator_type *e) { - struct task_struct *g, *p; + /* unregister */ + spin_lock(&elv_list_lock); + list_del_init(&e->list); + spin_unlock(&elv_list_lock); /* - * Iterate every thread in the process to remove the io contexts. + * Destroy icq_cache if it exists. icq's are RCU managed. Make + * sure all RCU operations are complete before proceeding. */ - if (e->ops.trim) { - read_lock(&tasklist_lock); - do_each_thread(g, p) { - task_lock(p); - if (p->io_context) - e->ops.trim(p->io_context); - task_unlock(p); - } while_each_thread(g, p); - read_unlock(&tasklist_lock); + if (e->icq_cache) { + rcu_barrier(); + kmem_cache_destroy(e->icq_cache); + e->icq_cache = NULL; } - - spin_lock(&elv_list_lock); - list_del_init(&e->list); - spin_unlock(&elv_list_lock); } EXPORT_SYMBOL_GPL(elv_unregister); @@ -944,54 +955,41 @@ EXPORT_SYMBOL_GPL(elv_unregister); static int elevator_switch(struct request_queue *q, struct elevator_type *new_e) { struct elevator_queue *old_elevator, *e; - void *data; int err; - /* - * Allocate new elevator - */ + /* allocate new elevator */ e = elevator_alloc(q, new_e); if (!e) return -ENOMEM; - data = elevator_init_queue(q, e); - if (!data) { + err = elevator_init_queue(q, e); + if (err) { kobject_put(&e->kobj); - return -ENOMEM; + return err; } - /* - * Turn on BYPASS and drain all requests w/ elevator private data - */ + /* turn on BYPASS and drain all requests w/ elevator private data */ elv_quiesce_start(q); - /* - * Remember old elevator. - */ - old_elevator = q->elevator; - - /* - * attach and start new elevator - */ - spin_lock_irq(q->queue_lock); - elevator_attach(q, e, data); - spin_unlock_irq(q->queue_lock); - - if (old_elevator->registered) { - __elv_unregister_queue(old_elevator); - - err = elv_register_queue(q); + /* unregister old queue, register new one and kill old elevator */ + if (q->elevator->registered) { + elv_unregister_queue(q); + err = __elv_register_queue(q, e); if (err) goto fail_register; } - /* - * finally exit old elevator and turn off BYPASS. - */ + /* done, clear io_cq's, switch elevators and turn off BYPASS */ + spin_lock_irq(q->queue_lock); + ioc_clear_queue(q); + old_elevator = q->elevator; + q->elevator = e; + spin_unlock_irq(q->queue_lock); + elevator_exit(old_elevator); elv_quiesce_end(q); - blk_add_trace_msg(q, "elv switch: %s", e->elevator_type->elevator_name); + blk_add_trace_msg(q, "elv switch: %s", e->type->elevator_name); return 0; @@ -1001,7 +999,6 @@ fail_register: * one again (along with re-adding the sysfs dir) */ elevator_exit(e); - q->elevator = old_elevator; elv_register_queue(q); elv_quiesce_end(q); @@ -1026,7 +1023,7 @@ int elevator_change(struct request_queue *q, const char *name) return -EINVAL; } - if (!strcmp(elevator_name, q->elevator->elevator_type->elevator_name)) { + if (!strcmp(elevator_name, q->elevator->type->elevator_name)) { elevator_put(e); return 0; } @@ -1061,7 +1058,7 @@ ssize_t elv_iosched_show(struct request_queue *q, char *name) if (!q->elevator || !blk_queue_stackable(q)) return sprintf(name, "none\n"); - elv = e->elevator_type; + elv = e->type; spin_lock(&elv_list_lock); list_for_each_entry(__e, &elv_list, list) { |