X-Git-Url: http://pileus.org/git/?a=blobdiff_plain;f=block%2Felevator.c;h=6a55d418896f5ceee0042da69c0177c495219cbc;hb=51eab603f5c86dd1eae4c525df3e7f7eeab401d6;hp=f016855a46b094628190f68e698ae21a936912e6;hpb=d1000edd5d64cc316d3f45c8d00797b778cf7e41;p=~andy%2Flinux diff --git a/block/elevator.c b/block/elevator.c index f016855a46b..6a55d418896 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -38,6 +38,7 @@ #include #include "blk.h" +#include "blk-cgroup.h" static DEFINE_SPINLOCK(elv_list_lock); static LIST_HEAD(elv_list); @@ -121,15 +122,6 @@ static struct elevator_type *elevator_get(const char *name) return e; } -static int elevator_init_queue(struct request_queue *q, - struct elevator_queue *eq) -{ - 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]; static int __init elevator_setup(char *str) @@ -188,7 +180,6 @@ static void elevator_release(struct kobject *kobj) int elevator_init(struct request_queue *q, char *name) { struct elevator_type *e = NULL; - struct elevator_queue *eq; int err; if (unlikely(q->elevator)) @@ -222,17 +213,16 @@ int elevator_init(struct request_queue *q, char *name) } } - eq = elevator_alloc(q, e); - if (!eq) + q->elevator = elevator_alloc(q, e); + if (!q->elevator) return -ENOMEM; - err = elevator_init_queue(q, eq); + err = e->ops.elevator_init_fn(q); if (err) { - kobject_put(&eq->kobj); + kobject_put(&q->elevator->kobj); return err; } - q->elevator = eq; return 0; } EXPORT_SYMBOL(elevator_init); @@ -564,25 +554,6 @@ void elv_drain_elevator(struct request_queue *q) } } -void elv_quiesce_start(struct request_queue *q) -{ - if (!q->elevator) - return; - - spin_lock_irq(q->queue_lock); - queue_flag_set(QUEUE_FLAG_ELVSWITCH, q); - spin_unlock_irq(q->queue_lock); - - blk_drain_queue(q, false); -} - -void elv_quiesce_end(struct request_queue *q) -{ - spin_lock_irq(q->queue_lock); - queue_flag_clear(QUEUE_FLAG_ELVSWITCH, q); - spin_unlock_irq(q->queue_lock); -} - void __elv_add_request(struct request_queue *q, struct request *rq, int where) { trace_block_rq_insert(q, rq); @@ -692,12 +663,13 @@ struct request *elv_former_request(struct request_queue *q, struct request *rq) return NULL; } -int elv_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask) +int elv_set_request(struct request_queue *q, struct request *rq, + struct bio *bio, gfp_t gfp_mask) { struct elevator_queue *e = q->elevator; if (e->type->ops.elevator_set_req_fn) - return e->type->ops.elevator_set_req_fn(q, rq, gfp_mask); + return e->type->ops.elevator_set_req_fn(q, rq, bio, gfp_mask); return 0; } @@ -801,8 +773,9 @@ static struct kobj_type elv_ktype = { .release = elevator_release, }; -int __elv_register_queue(struct request_queue *q, struct elevator_queue *e) +int elv_register_queue(struct request_queue *q) { + struct elevator_queue *e = q->elevator; int error; error = kobject_add(&e->kobj, &q->kobj, "%s", "iosched"); @@ -820,11 +793,6 @@ int __elv_register_queue(struct request_queue *q, struct elevator_queue *e) } return error; } - -int elv_register_queue(struct request_queue *q) -{ - return __elv_register_queue(q, q->elevator); -} EXPORT_SYMBOL(elv_register_queue); void elv_unregister_queue(struct request_queue *q) @@ -907,53 +875,60 @@ EXPORT_SYMBOL_GPL(elv_unregister); */ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e) { - struct elevator_queue *old_elevator, *e; + struct elevator_queue *old = q->elevator; + bool registered = old->registered; int err; - /* allocate new elevator */ - e = elevator_alloc(q, new_e); - if (!e) - return -ENOMEM; + /* + * Turn on BYPASS and drain all requests w/ elevator private data. + * Block layer doesn't call into a quiesced elevator - all requests + * are directly put on the dispatch list without elevator data + * using INSERT_BACK. All requests have SOFTBARRIER set and no + * merge happens either. + */ + blk_queue_bypass_start(q); + + /* unregister and clear all auxiliary data of the old elevator */ + if (registered) + elv_unregister_queue(q); + + spin_lock_irq(q->queue_lock); + ioc_clear_queue(q); + spin_unlock_irq(q->queue_lock); - err = elevator_init_queue(q, e); + /* allocate, init and register new elevator */ + err = -ENOMEM; + q->elevator = elevator_alloc(q, new_e); + if (!q->elevator) + goto fail_init; + + err = new_e->ops.elevator_init_fn(q); if (err) { - kobject_put(&e->kobj); - return err; + kobject_put(&q->elevator->kobj); + goto fail_init; } - /* turn on BYPASS and drain all requests w/ elevator private data */ - elv_quiesce_start(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 (registered) { + err = elv_register_queue(q); if (err) goto fail_register; } - /* 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); + /* done, kill the old one and finish */ + elevator_exit(old); + blk_queue_bypass_end(q); - blk_add_trace_msg(q, "elv switch: %s", e->type->elevator_name); + blk_add_trace_msg(q, "elv switch: %s", new_e->elevator_name); return 0; fail_register: - /* - * switch failed, exit the new io scheduler and reattach the old - * one again (along with re-adding the sysfs dir) - */ - elevator_exit(e); + elevator_exit(q->elevator); +fail_init: + /* switch failed, restore and re-register old elevator */ + q->elevator = old; elv_register_queue(q); - elv_quiesce_end(q); + blk_queue_bypass_end(q); return err; }