diff options
Diffstat (limited to 'block/elevator.c')
| -rw-r--r-- | block/elevator.c | 123 |
1 files changed, 109 insertions, 14 deletions
diff --git a/block/elevator.c b/block/elevator.c index cff1102dac9..cbbc36ba016 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -239,6 +239,8 @@ int elevator_init(request_queue_t *q, char *name) return ret; } +EXPORT_SYMBOL(elevator_init); + void elevator_exit(elevator_t *e) { mutex_lock(&e->sysfs_lock); @@ -250,6 +252,8 @@ void elevator_exit(elevator_t *e) kobject_put(&e->kobj); } +EXPORT_SYMBOL(elevator_exit); + static inline void __elv_rqhash_del(struct request *rq) { hlist_del_init(&rq->hash); @@ -298,9 +302,68 @@ static struct request *elv_rqhash_find(request_queue_t *q, sector_t offset) } /* + * RB-tree support functions for inserting/lookup/removal of requests + * in a sorted RB tree. + */ +struct request *elv_rb_add(struct rb_root *root, struct request *rq) +{ + struct rb_node **p = &root->rb_node; + struct rb_node *parent = NULL; + struct request *__rq; + + while (*p) { + parent = *p; + __rq = rb_entry(parent, struct request, rb_node); + + if (rq->sector < __rq->sector) + p = &(*p)->rb_left; + else if (rq->sector > __rq->sector) + p = &(*p)->rb_right; + else + return __rq; + } + + rb_link_node(&rq->rb_node, parent, p); + rb_insert_color(&rq->rb_node, root); + return NULL; +} + +EXPORT_SYMBOL(elv_rb_add); + +void elv_rb_del(struct rb_root *root, struct request *rq) +{ + BUG_ON(RB_EMPTY_NODE(&rq->rb_node)); + rb_erase(&rq->rb_node, root); + RB_CLEAR_NODE(&rq->rb_node); +} + +EXPORT_SYMBOL(elv_rb_del); + +struct request *elv_rb_find(struct rb_root *root, sector_t sector) +{ + struct rb_node *n = root->rb_node; + struct request *rq; + + while (n) { + rq = rb_entry(n, struct request, rb_node); + + if (sector < rq->sector) + n = n->rb_left; + else if (sector > rq->sector) + n = n->rb_right; + else + return rq; + } + + return NULL; +} + +EXPORT_SYMBOL(elv_rb_find); + +/* * Insert rq into dispatch queue of q. Queue lock must be held on - * entry. If sort != 0, rq is sort-inserted; otherwise, rq will be - * appended to the dispatch queue. To be used by specific elevators. + * entry. rq is sort insted into the dispatch queue. To be used by + * specific elevators. */ void elv_dispatch_sort(request_queue_t *q, struct request *rq) { @@ -335,8 +398,12 @@ void elv_dispatch_sort(request_queue_t *q, struct request *rq) list_add(&rq->queuelist, entry); } +EXPORT_SYMBOL(elv_dispatch_sort); + /* - * This should be in elevator.h, but that requires pulling in rq and q + * Insert rq into dispatch queue of q. Queue lock must be held on + * entry. rq is added to the back of the dispatch queue. To be used by + * specific elevators. */ void elv_dispatch_add_tail(struct request_queue *q, struct request *rq) { @@ -352,6 +419,8 @@ void elv_dispatch_add_tail(struct request_queue *q, struct request *rq) list_add_tail(&rq->queuelist, &q->queue_head); } +EXPORT_SYMBOL(elv_dispatch_add_tail); + int elv_merge(request_queue_t *q, struct request **req, struct bio *bio) { elevator_t *e = q->elevator; @@ -384,14 +453,15 @@ int elv_merge(request_queue_t *q, struct request **req, struct bio *bio) return ELEVATOR_NO_MERGE; } -void elv_merged_request(request_queue_t *q, struct request *rq) +void elv_merged_request(request_queue_t *q, struct request *rq, int type) { elevator_t *e = q->elevator; if (e->ops->elevator_merged_fn) - e->ops->elevator_merged_fn(q, rq); + e->ops->elevator_merged_fn(q, rq, type); - elv_rqhash_reposition(q, rq); + if (type == ELEVATOR_BACK_MERGE) + elv_rqhash_reposition(q, rq); q->last_merge = rq; } @@ -577,6 +647,8 @@ void __elv_add_request(request_queue_t *q, struct request *rq, int where, elv_insert(q, rq, where); } +EXPORT_SYMBOL(__elv_add_request); + void elv_add_request(request_queue_t *q, struct request *rq, int where, int plug) { @@ -587,6 +659,8 @@ void elv_add_request(request_queue_t *q, struct request *rq, int where, spin_unlock_irqrestore(q->queue_lock, flags); } +EXPORT_SYMBOL(elv_add_request); + static inline struct request *__elv_next_request(request_queue_t *q) { struct request *rq; @@ -670,6 +744,8 @@ struct request *elv_next_request(request_queue_t *q) return rq; } +EXPORT_SYMBOL(elv_next_request); + void elv_dequeue_request(request_queue_t *q, struct request *rq) { BUG_ON(list_empty(&rq->queuelist)); @@ -686,6 +762,8 @@ void elv_dequeue_request(request_queue_t *q, struct request *rq) q->in_flight++; } +EXPORT_SYMBOL(elv_dequeue_request); + int elv_queue_empty(request_queue_t *q) { elevator_t *e = q->elevator; @@ -699,6 +777,8 @@ int elv_queue_empty(request_queue_t *q) return 1; } +EXPORT_SYMBOL(elv_queue_empty); + struct request *elv_latter_request(request_queue_t *q, struct request *rq) { elevator_t *e = q->elevator; @@ -1025,11 +1105,26 @@ ssize_t elv_iosched_show(request_queue_t *q, char *name) return len; } -EXPORT_SYMBOL(elv_dispatch_sort); -EXPORT_SYMBOL(elv_add_request); -EXPORT_SYMBOL(__elv_add_request); -EXPORT_SYMBOL(elv_next_request); -EXPORT_SYMBOL(elv_dequeue_request); -EXPORT_SYMBOL(elv_queue_empty); -EXPORT_SYMBOL(elevator_exit); -EXPORT_SYMBOL(elevator_init); +struct request *elv_rb_former_request(request_queue_t *q, struct request *rq) +{ + struct rb_node *rbprev = rb_prev(&rq->rb_node); + + if (rbprev) + return rb_entry_rq(rbprev); + + return NULL; +} + +EXPORT_SYMBOL(elv_rb_former_request); + +struct request *elv_rb_latter_request(request_queue_t *q, struct request *rq) +{ + struct rb_node *rbnext = rb_next(&rq->rb_node); + + if (rbnext) + return rb_entry_rq(rbnext); + + return NULL; +} + +EXPORT_SYMBOL(elv_rb_latter_request); |