X-Git-Url: https://git.karo-electronics.de/?a=blobdiff_plain;f=block%2Felevator.c;h=1d0759178e4b49710c6cb90c538fc6d0c897e126;hb=2dede2d8e925f4c2cb4e136b14df127685e15dd3;hp=d4a49a3df829674bbb4bb476f271fc721c6fa9f3;hpb=7669a22592fc6cc7ac03f55a7db8d23ce938f1dc;p=karo-tx-linux.git diff --git a/block/elevator.c b/block/elevator.c index d4a49a3df829..1d0759178e4b 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -1,6 +1,4 @@ /* - * linux/drivers/block/elevator.c - * * Block device elevator/IO-scheduler. * * Copyright (C) 2000 Andrea Arcangeli SuSE @@ -66,7 +64,7 @@ inline int elv_rq_merge_ok(struct request *rq, struct bio *bio) } EXPORT_SYMBOL(elv_rq_merge_ok); -inline int elv_try_merge(struct request *__rq, struct bio *bio) +static inline int elv_try_merge(struct request *__rq, struct bio *bio) { int ret = ELEVATOR_NO_MERGE; @@ -82,7 +80,6 @@ inline int elv_try_merge(struct request *__rq, struct bio *bio) return ret; } -EXPORT_SYMBOL(elv_try_merge); static struct elevator_type *elevator_find(const char *name) { @@ -155,9 +152,10 @@ static void elevator_setup_default(void) /* * If the given scheduler is not available, fall back to no-op. */ - if (!(e = elevator_find(chosen_elevator))) + if ((e = elevator_find(chosen_elevator))) + elevator_put(e); + else strcpy(chosen_elevator, "noop"); - elevator_put(e); } static int __init elevator_setup(char *str) @@ -190,14 +188,14 @@ int elevator_init(request_queue_t *q, char *name) eq = kmalloc(sizeof(struct elevator_queue), GFP_KERNEL); if (!eq) { - elevator_put(e->elevator_type); + elevator_put(e); return -ENOMEM; } ret = elevator_attach(q, e, eq); if (ret) { kfree(eq); - elevator_put(e->elevator_type); + elevator_put(e); } return ret; @@ -225,6 +223,7 @@ void elv_dispatch_sort(request_queue_t *q, struct request *rq) if (q->last_merge == rq) q->last_merge = NULL; + q->nr_sorted--; boundary = q->end_sector; @@ -283,6 +282,7 @@ void elv_merge_requests(request_queue_t *q, struct request *rq, if (e->ops->elevator_merge_req_fn) e->ops->elevator_merge_req_fn(q, rq, next); + q->nr_sorted--; q->last_merge = rq; } @@ -303,21 +303,38 @@ void elv_requeue_request(request_queue_t *q, struct request *rq) rq->flags &= ~REQ_STARTED; - /* - * if this is the flush, requeue the original instead and drop the flush - */ - if (rq->flags & REQ_BAR_FLUSH) { - clear_bit(QUEUE_FLAG_FLUSH, &q->queue_flags); - rq = rq->end_io_data; - } + __elv_add_request(q, rq, ELEVATOR_INSERT_REQUEUE, 0); +} - __elv_add_request(q, rq, ELEVATOR_INSERT_FRONT, 0); +static void elv_drain_elevator(request_queue_t *q) +{ + static int printed; + while (q->elevator->ops->elevator_dispatch_fn(q, 1)) + ; + if (q->nr_sorted == 0) + return; + if (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); + } } void __elv_add_request(request_queue_t *q, struct request *rq, int where, int plug) { + struct list_head *pos; + unsigned ordseq; + + if (q->ordcolor) + rq->flags |= REQ_ORDERED_COLOR; + if (rq->flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)) { + /* + * toggle ordered color + */ + q->ordcolor ^= 1; + /* * barriers implicitly indicate back insertion */ @@ -348,9 +365,7 @@ void __elv_add_request(request_queue_t *q, struct request *rq, int where, case ELEVATOR_INSERT_BACK: rq->flags |= REQ_SOFTBARRIER; - - while (q->elevator->ops->elevator_dispatch_fn(q, 1)) - ; + elv_drain_elevator(q); list_add_tail(&rq->queuelist, &q->queue_head); /* * We kick the queue here for the following reasons. @@ -369,6 +384,7 @@ void __elv_add_request(request_queue_t *q, struct request *rq, int where, case ELEVATOR_INSERT_SORT: BUG_ON(!blk_fs_request(rq)); rq->flags |= REQ_SORTED; + q->nr_sorted++; if (q->last_merge == NULL && rq_mergeable(rq)) q->last_merge = rq; /* @@ -379,6 +395,30 @@ void __elv_add_request(request_queue_t *q, struct request *rq, int where, q->elevator->ops->elevator_add_req_fn(q, rq); break; + case ELEVATOR_INSERT_REQUEUE: + /* + * If ordered flush isn't in progress, we do front + * insertion; otherwise, requests should be requeued + * in ordseq order. + */ + rq->flags |= REQ_SOFTBARRIER; + + if (q->ordseq == 0) { + list_add(&rq->queuelist, &q->queue_head); + break; + } + + ordseq = blk_ordered_req_seq(rq); + + list_for_each(pos, &q->queue_head) { + struct request *pos_rq = list_entry_rq(pos); + if (ordseq <= blk_ordered_req_seq(pos_rq)) + break; + } + + list_add_tail(&rq->queuelist, pos); + break; + default: printk(KERN_ERR "%s: bad insertion point %d\n", __FUNCTION__, where); @@ -408,25 +448,16 @@ static inline struct request *__elv_next_request(request_queue_t *q) { struct request *rq; - if (unlikely(list_empty(&q->queue_head) && - !q->elevator->ops->elevator_dispatch_fn(q, 0))) - return NULL; - - rq = list_entry_rq(q->queue_head.next); - - /* - * if this is a barrier write and the device has to issue a - * flush sequence to support it, check how far we are - */ - if (blk_fs_request(rq) && blk_barrier_rq(rq)) { - BUG_ON(q->ordered == QUEUE_ORDERED_NONE); + while (1) { + while (!list_empty(&q->queue_head)) { + rq = list_entry_rq(q->queue_head.next); + if (blk_do_ordered(q, &rq)) + return rq; + } - if (q->ordered == QUEUE_ORDERED_FLUSH && - !blk_barrier_preflush(rq)) - rq = blk_start_pre_flush(q, rq); + if (!q->elevator->ops->elevator_dispatch_fn(q, 0)) + return NULL; } - - return rq; } struct request *elv_next_request(request_queue_t *q) @@ -484,7 +515,7 @@ struct request *elv_next_request(request_queue_t *q) blkdev_dequeue_request(rq); rq->flags |= REQ_QUIET; end_that_request_chunk(rq, 0, nr_bytes); - end_that_request_last(rq); + end_that_request_last(rq, 0); } else { printk(KERN_ERR "%s: bad return=%d\n", __FUNCTION__, ret); @@ -525,33 +556,19 @@ int elv_queue_empty(request_queue_t *q) struct request *elv_latter_request(request_queue_t *q, struct request *rq) { - struct list_head *next; - elevator_t *e = q->elevator; if (e->ops->elevator_latter_req_fn) return e->ops->elevator_latter_req_fn(q, rq); - - next = rq->queuelist.next; - if (next != &q->queue_head && next != &rq->queuelist) - return list_entry_rq(next); - return NULL; } struct request *elv_former_request(request_queue_t *q, struct request *rq) { - struct list_head *prev; - elevator_t *e = q->elevator; if (e->ops->elevator_former_req_fn) return e->ops->elevator_former_req_fn(q, rq); - - prev = rq->queuelist.prev; - if (prev != &q->queue_head && prev != &rq->queuelist) - return list_entry_rq(prev); - return NULL; } @@ -597,6 +614,20 @@ void elv_completed_request(request_queue_t *q, struct request *rq) if (blk_sorted_rq(rq) && e->ops->elevator_completed_req_fn) e->ops->elevator_completed_req_fn(q, rq); } + + /* + * Check if the queue is waiting for fs requests to be + * drained for flush sequence. + */ + if (unlikely(q->ordseq)) { + struct request *first_rq = list_entry_rq(q->queue_head.next); + if (q->in_flight == 0 && + blk_ordered_cur_seq(q) == QUEUE_ORDSEQ_DRAIN && + blk_ordered_req_seq(first_rq) > QUEUE_ORDSEQ_DRAIN) { + blk_ordered_complete_seq(q, QUEUE_ORDSEQ_DRAIN, 0); + q->request_fn(q); + } + } } int elv_register_queue(struct request_queue *q) @@ -691,13 +722,15 @@ static void elevator_switch(request_queue_t *q, struct elevator_type *new_e) set_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags); - while (q->elevator->ops->elevator_dispatch_fn(q, 1)) - ; + elv_drain_elevator(q); while (q->rq.elvpriv) { + blk_remove_plug(q); + q->request_fn(q); spin_unlock_irq(q->queue_lock); msleep(10); spin_lock_irq(q->queue_lock); + elv_drain_elevator(q); } spin_unlock_irq(q->queue_lock); @@ -744,13 +777,15 @@ error: ssize_t elv_iosched_store(request_queue_t *q, const char *name, size_t count) { char elevator_name[ELV_NAME_MAX]; + size_t len; struct elevator_type *e; - memset(elevator_name, 0, sizeof(elevator_name)); - strncpy(elevator_name, name, sizeof(elevator_name)); + elevator_name[sizeof(elevator_name) - 1] = '\0'; + strncpy(elevator_name, name, sizeof(elevator_name) - 1); + len = strlen(elevator_name); - if (elevator_name[strlen(elevator_name) - 1] == '\n') - elevator_name[strlen(elevator_name) - 1] = '\0'; + if (len && elevator_name[len - 1] == '\n') + elevator_name[len - 1] = '\0'; e = elevator_get(elevator_name); if (!e) {