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block/noop-iosched.c
2.54 KB
1da177e4c Linux-2.6.12-rc2 |
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/* * elevator noop */ #include <linux/blkdev.h> #include <linux/elevator.h> #include <linux/bio.h> #include <linux/module.h> #include <linux/init.h> |
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struct noop_data { struct list_head queue; }; static void noop_merged_requests(request_queue_t *q, struct request *rq, struct request *next) { list_del_init(&next->queuelist); } static int noop_dispatch(request_queue_t *q, int force) { struct noop_data *nd = q->elevator->elevator_data; if (!list_empty(&nd->queue)) { struct request *rq; rq = list_entry(nd->queue.next, struct request, queuelist); list_del_init(&rq->queuelist); elv_dispatch_sort(q, rq); return 1; } return 0; } static void noop_add_request(request_queue_t *q, struct request *rq) { struct noop_data *nd = q->elevator->elevator_data; list_add_tail(&rq->queuelist, &nd->queue); } static int noop_queue_empty(request_queue_t *q) |
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{ |
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struct noop_data *nd = q->elevator->elevator_data; return list_empty(&nd->queue); } static struct request * noop_former_request(request_queue_t *q, struct request *rq) { struct noop_data *nd = q->elevator->elevator_data; if (rq->queuelist.prev == &nd->queue) return NULL; return list_entry(rq->queuelist.prev, struct request, queuelist); } static struct request * noop_latter_request(request_queue_t *q, struct request *rq) { struct noop_data *nd = q->elevator->elevator_data; if (rq->queuelist.next == &nd->queue) return NULL; return list_entry(rq->queuelist.next, struct request, queuelist); |
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} |
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static void *noop_init_queue(request_queue_t *q) |
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{ |
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struct noop_data *nd; |
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nd = kmalloc_node(sizeof(*nd), GFP_KERNEL, q->node); |
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if (!nd) |
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return NULL; |
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INIT_LIST_HEAD(&nd->queue); |
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return nd; |
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} |
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static void noop_exit_queue(elevator_t *e) { struct noop_data *nd = e->elevator_data; BUG_ON(!list_empty(&nd->queue)); kfree(nd); } |
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static struct elevator_type elevator_noop = { .ops = { |
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.elevator_merge_req_fn = noop_merged_requests, .elevator_dispatch_fn = noop_dispatch, .elevator_add_req_fn = noop_add_request, .elevator_queue_empty_fn = noop_queue_empty, .elevator_former_req_fn = noop_former_request, .elevator_latter_req_fn = noop_latter_request, .elevator_init_fn = noop_init_queue, .elevator_exit_fn = noop_exit_queue, |
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}, .elevator_name = "noop", .elevator_owner = THIS_MODULE, }; static int __init noop_init(void) { return elv_register(&elevator_noop); } static void __exit noop_exit(void) { elv_unregister(&elevator_noop); } module_init(noop_init); module_exit(noop_exit); MODULE_AUTHOR("Jens Axboe"); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("No-op IO scheduler"); |