Root/
1 | /* |
2 | * elevator noop |
3 | */ |
4 | #include <linux/blkdev.h> |
5 | #include <linux/elevator.h> |
6 | #include <linux/bio.h> |
7 | #include <linux/module.h> |
8 | #include <linux/slab.h> |
9 | #include <linux/init.h> |
10 | |
11 | struct noop_data { |
12 | struct list_head queue; |
13 | }; |
14 | |
15 | static void noop_merged_requests(struct request_queue *q, struct request *rq, |
16 | struct request *next) |
17 | { |
18 | list_del_init(&next->queuelist); |
19 | } |
20 | |
21 | static int noop_dispatch(struct request_queue *q, int force) |
22 | { |
23 | struct noop_data *nd = q->elevator->elevator_data; |
24 | |
25 | if (!list_empty(&nd->queue)) { |
26 | struct request *rq; |
27 | rq = list_entry(nd->queue.next, struct request, queuelist); |
28 | list_del_init(&rq->queuelist); |
29 | elv_dispatch_sort(q, rq); |
30 | return 1; |
31 | } |
32 | return 0; |
33 | } |
34 | |
35 | static void noop_add_request(struct request_queue *q, struct request *rq) |
36 | { |
37 | struct noop_data *nd = q->elevator->elevator_data; |
38 | |
39 | list_add_tail(&rq->queuelist, &nd->queue); |
40 | } |
41 | |
42 | static struct request * |
43 | noop_former_request(struct request_queue *q, struct request *rq) |
44 | { |
45 | struct noop_data *nd = q->elevator->elevator_data; |
46 | |
47 | if (rq->queuelist.prev == &nd->queue) |
48 | return NULL; |
49 | return list_entry(rq->queuelist.prev, struct request, queuelist); |
50 | } |
51 | |
52 | static struct request * |
53 | noop_latter_request(struct request_queue *q, struct request *rq) |
54 | { |
55 | struct noop_data *nd = q->elevator->elevator_data; |
56 | |
57 | if (rq->queuelist.next == &nd->queue) |
58 | return NULL; |
59 | return list_entry(rq->queuelist.next, struct request, queuelist); |
60 | } |
61 | |
62 | static int noop_init_queue(struct request_queue *q, struct elevator_type *e) |
63 | { |
64 | struct noop_data *nd; |
65 | struct elevator_queue *eq; |
66 | |
67 | eq = elevator_alloc(q, e); |
68 | if (!eq) |
69 | return -ENOMEM; |
70 | |
71 | nd = kmalloc_node(sizeof(*nd), GFP_KERNEL, q->node); |
72 | if (!nd) { |
73 | kobject_put(&eq->kobj); |
74 | return -ENOMEM; |
75 | } |
76 | eq->elevator_data = nd; |
77 | |
78 | INIT_LIST_HEAD(&nd->queue); |
79 | |
80 | spin_lock_irq(q->queue_lock); |
81 | q->elevator = eq; |
82 | spin_unlock_irq(q->queue_lock); |
83 | return 0; |
84 | } |
85 | |
86 | static void noop_exit_queue(struct elevator_queue *e) |
87 | { |
88 | struct noop_data *nd = e->elevator_data; |
89 | |
90 | BUG_ON(!list_empty(&nd->queue)); |
91 | kfree(nd); |
92 | } |
93 | |
94 | static struct elevator_type elevator_noop = { |
95 | .ops = { |
96 | .elevator_merge_req_fn = noop_merged_requests, |
97 | .elevator_dispatch_fn = noop_dispatch, |
98 | .elevator_add_req_fn = noop_add_request, |
99 | .elevator_former_req_fn = noop_former_request, |
100 | .elevator_latter_req_fn = noop_latter_request, |
101 | .elevator_init_fn = noop_init_queue, |
102 | .elevator_exit_fn = noop_exit_queue, |
103 | }, |
104 | .elevator_name = "noop", |
105 | .elevator_owner = THIS_MODULE, |
106 | }; |
107 | |
108 | static int __init noop_init(void) |
109 | { |
110 | return elv_register(&elevator_noop); |
111 | } |
112 | |
113 | static void __exit noop_exit(void) |
114 | { |
115 | elv_unregister(&elevator_noop); |
116 | } |
117 | |
118 | module_init(noop_init); |
119 | module_exit(noop_exit); |
120 | |
121 | |
122 | MODULE_AUTHOR("Jens Axboe"); |
123 | MODULE_LICENSE("GPL"); |
124 | MODULE_DESCRIPTION("No-op IO scheduler"); |
125 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9