X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=block%2Felevator.c;h=d00b283f31d21fdb5256754b75336e1005fb7eed;hb=94f6c59dcf16f10a20fbe3d1f098b159433f94bd;hp=0232df2b16e6a9bbec94606554a5fd1dc0357961;hpb=e17a9489b4a686bb5e9615e1d375c67619cb99c5;p=safe%2Fjmp%2Flinux-2.6 diff --git a/block/elevator.c b/block/elevator.c index 0232df2..d00b283 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -33,6 +33,7 @@ #include #include #include +#include #include @@ -120,21 +121,16 @@ static struct elevator_type *elevator_get(const char *name) return e; } -static int elevator_attach(request_queue_t *q, struct elevator_type *e, - struct elevator_queue *eq) +static void *elevator_init_queue(request_queue_t *q, struct elevator_queue *eq) { - int ret = 0; - - memset(eq, 0, sizeof(*eq)); - eq->ops = &e->ops; - eq->elevator_type = e; + return eq->ops->elevator_init_fn(q, eq); +} +static void elevator_attach(request_queue_t *q, struct elevator_queue *eq, + void *data) +{ q->elevator = eq; - - if (eq->ops->elevator_init_fn) - ret = eq->ops->elevator_init_fn(q, eq); - - return ret; + eq->elevator_data = data; } static char chosen_elevator[16]; @@ -149,16 +145,43 @@ static int __init elevator_setup(char *str) strcpy(chosen_elevator, "anticipatory"); else strncpy(chosen_elevator, str, sizeof(chosen_elevator) - 1); - return 0; + return 1; } __setup("elevator=", elevator_setup); +static struct kobj_type elv_ktype; + +static elevator_t *elevator_alloc(struct elevator_type *e) +{ + elevator_t *eq = kmalloc(sizeof(elevator_t), GFP_KERNEL); + if (eq) { + memset(eq, 0, sizeof(*eq)); + eq->ops = &e->ops; + eq->elevator_type = e; + kobject_init(&eq->kobj); + snprintf(eq->kobj.name, KOBJ_NAME_LEN, "%s", "iosched"); + eq->kobj.ktype = &elv_ktype; + mutex_init(&eq->sysfs_lock); + } else { + elevator_put(e); + } + return eq; +} + +static void elevator_release(struct kobject *kobj) +{ + elevator_t *e = container_of(kobj, elevator_t, kobj); + elevator_put(e->elevator_type); + kfree(e); +} + int elevator_init(request_queue_t *q, char *name) { struct elevator_type *e = NULL; struct elevator_queue *eq; int ret = 0; + void *data; INIT_LIST_HEAD(&q->queue_head); q->last_merge = NULL; @@ -176,29 +199,29 @@ int elevator_init(request_queue_t *q, char *name) e = elevator_get("noop"); } - eq = kmalloc(sizeof(struct elevator_queue), GFP_KERNEL); - if (!eq) { - elevator_put(e); + eq = elevator_alloc(e); + if (!eq) return -ENOMEM; - } - ret = elevator_attach(q, e, eq); - if (ret) { - kfree(eq); - elevator_put(e); + data = elevator_init_queue(q, eq); + if (!data) { + kobject_put(&eq->kobj); + return -ENOMEM; } + elevator_attach(q, eq, data); return ret; } void elevator_exit(elevator_t *e) { + mutex_lock(&e->sysfs_lock); if (e->ops->elevator_exit_fn) e->ops->elevator_exit_fn(e); + e->ops = NULL; + mutex_unlock(&e->sysfs_lock); - elevator_put(e->elevator_type); - e->elevator_type = NULL; - kfree(e); + kobject_put(&e->kobj); } /* @@ -314,6 +337,9 @@ void elv_insert(request_queue_t *q, struct request *rq, int where) { struct list_head *pos; unsigned ordseq; + int unplug_it = 1; + + blk_add_trace_rq(q, rq, BLK_TA_INSERT); rq->q = q; @@ -378,6 +404,11 @@ void elv_insert(request_queue_t *q, struct request *rq, int where) } list_add_tail(&rq->queuelist, pos); + /* + * most requeues happen because of a busy condition, don't + * force unplug of the queue for that case. + */ + unplug_it = 0; break; default: @@ -386,7 +417,7 @@ void elv_insert(request_queue_t *q, struct request *rq, int where) BUG(); } - if (blk_queue_plugged(q)) { + if (unplug_it && blk_queue_plugged(q)) { int nrq = q->rq.count[READ] + q->rq.count[WRITE] - q->in_flight; @@ -481,6 +512,7 @@ struct request *elv_next_request(request_queue_t *q) * not be passed by new incoming requests */ rq->flags |= REQ_STARTED; + blk_add_trace_rq(q, rq, BLK_TA_ISSUE); } if (!q->boundary_rq || q->boundary_rq == rq) { @@ -627,34 +659,89 @@ void elv_completed_request(request_queue_t *q, struct request *rq) } } -int elv_register_queue(struct request_queue *q) +#define to_elv(atr) container_of((atr), struct elv_fs_entry, attr) + +static ssize_t +elv_attr_show(struct kobject *kobj, struct attribute *attr, char *page) { - elevator_t *e = q->elevator; + elevator_t *e = container_of(kobj, elevator_t, kobj); + struct elv_fs_entry *entry = to_elv(attr); + ssize_t error; + + if (!entry->show) + return -EIO; + + mutex_lock(&e->sysfs_lock); + error = e->ops ? entry->show(e, page) : -ENOENT; + mutex_unlock(&e->sysfs_lock); + return error; +} - e->kobj.parent = kobject_get(&q->kobj); - if (!e->kobj.parent) - return -EBUSY; +static ssize_t +elv_attr_store(struct kobject *kobj, struct attribute *attr, + const char *page, size_t length) +{ + elevator_t *e = container_of(kobj, elevator_t, kobj); + struct elv_fs_entry *entry = to_elv(attr); + ssize_t error; - snprintf(e->kobj.name, KOBJ_NAME_LEN, "%s", "iosched"); - e->kobj.ktype = e->elevator_type->elevator_ktype; + if (!entry->store) + return -EIO; - return kobject_register(&e->kobj); + mutex_lock(&e->sysfs_lock); + error = e->ops ? entry->store(e, page, length) : -ENOENT; + mutex_unlock(&e->sysfs_lock); + return error; } -void elv_unregister_queue(struct request_queue *q) +static struct sysfs_ops elv_sysfs_ops = { + .show = elv_attr_show, + .store = elv_attr_store, +}; + +static struct kobj_type elv_ktype = { + .sysfs_ops = &elv_sysfs_ops, + .release = elevator_release, +}; + +int elv_register_queue(struct request_queue *q) { - if (q) { - elevator_t *e = q->elevator; - kobject_unregister(&e->kobj); - kobject_put(&q->kobj); + elevator_t *e = q->elevator; + int error; + + e->kobj.parent = &q->kobj; + + error = kobject_add(&e->kobj); + if (!error) { + struct elv_fs_entry *attr = e->elevator_type->elevator_attrs; + if (attr) { + while (attr->attr.name) { + if (sysfs_create_file(&e->kobj, &attr->attr)) + break; + attr++; + } + } + kobject_uevent(&e->kobj, KOBJ_ADD); } + return error; +} + +static void __elv_unregister_queue(elevator_t *e) +{ + kobject_uevent(&e->kobj, KOBJ_REMOVE); + kobject_del(&e->kobj); +} + +void elv_unregister_queue(struct request_queue *q) +{ + if (q) + __elv_unregister_queue(q->elevator); } int elv_register(struct elevator_type *e) { spin_lock_irq(&elv_list_lock); - if (elevator_find(e->elevator_name)) - BUG(); + BUG_ON(elevator_find(e->elevator_name)); list_add_tail(&e->list, &elv_list); spin_unlock_irq(&elv_list_lock); @@ -697,16 +784,23 @@ EXPORT_SYMBOL_GPL(elv_unregister); * need for the new one. this way we have a chance of going back to the old * one, if the new one fails init for some reason. */ -static void elevator_switch(request_queue_t *q, struct elevator_type *new_e) +static int elevator_switch(request_queue_t *q, struct elevator_type *new_e) { elevator_t *old_elevator, *e; + void *data; /* * Allocate new elevator */ - e = kmalloc(sizeof(elevator_t), GFP_KERNEL); + e = elevator_alloc(new_e); if (!e) - goto error; + return 0; + + data = elevator_init_queue(q, e); + if (!data) { + kobject_put(&e->kobj); + return 0; + } /* * Turn on BYPASS and drain all requests w/ elevator private data @@ -726,19 +820,19 @@ static void elevator_switch(request_queue_t *q, struct elevator_type *new_e) elv_drain_elevator(q); } - spin_unlock_irq(q->queue_lock); - /* - * unregister old elevator data + * Remember old elevator. */ - elv_unregister_queue(q); old_elevator = q->elevator; /* * attach and start new elevator */ - if (elevator_attach(q, new_e, e)) - goto fail; + elevator_attach(q, e, data); + + spin_unlock_irq(q->queue_lock); + + __elv_unregister_queue(old_elevator); if (elv_register_queue(q)) goto fail_register; @@ -748,7 +842,7 @@ static void elevator_switch(request_queue_t *q, struct elevator_type *new_e) */ elevator_exit(old_elevator); clear_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags); - return; + return 1; fail_register: /* @@ -756,15 +850,10 @@ fail_register: * one again (along with re-adding the sysfs dir) */ elevator_exit(e); - e = NULL; -fail: q->elevator = old_elevator; elv_register_queue(q); clear_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags); - kfree(e); -error: - elevator_put(new_e); - printk(KERN_ERR "elevator: switch to %s failed\n",new_e->elevator_name); + return 0; } ssize_t elv_iosched_store(request_queue_t *q, const char *name, size_t count) @@ -791,7 +880,8 @@ ssize_t elv_iosched_store(request_queue_t *q, const char *name, size_t count) return count; } - elevator_switch(q, e); + if (!elevator_switch(q, e)) + printk(KERN_ERR "elevator: switch to %s failed\n",elevator_name); return count; } @@ -821,10 +911,8 @@ ssize_t elv_iosched_show(request_queue_t *q, char *name) EXPORT_SYMBOL(elv_dispatch_sort); EXPORT_SYMBOL(elv_add_request); EXPORT_SYMBOL(__elv_add_request); -EXPORT_SYMBOL(elv_requeue_request); EXPORT_SYMBOL(elv_next_request); EXPORT_SYMBOL(elv_dequeue_request); EXPORT_SYMBOL(elv_queue_empty); -EXPORT_SYMBOL(elv_completed_request); EXPORT_SYMBOL(elevator_exit); EXPORT_SYMBOL(elevator_init);