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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 * Deadline i/o scheduler.
3 *
Jens Axboe0fe23472006-09-04 15:41:16 +02004 * Copyright (C) 2002 Jens Axboe <axboe@kernel.dk>
Linus Torvalds1da177e2005-04-16 15:20:36 -07005 */
6#include <linux/kernel.h>
7#include <linux/fs.h>
8#include <linux/blkdev.h>
9#include <linux/elevator.h>
10#include <linux/bio.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070011#include <linux/module.h>
12#include <linux/slab.h>
13#include <linux/init.h>
14#include <linux/compiler.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/rbtree.h>
16
17/*
18 * See Documentation/block/deadline-iosched.txt
19 */
Arjan van de Ven64100092006-01-06 09:46:02 +010020static const int read_expire = HZ / 2; /* max time before a read is submitted. */
21static const int write_expire = 5 * HZ; /* ditto for writes, these limits are SOFT! */
22static const int writes_starved = 2; /* max times reads can starve a write */
23static const int fifo_batch = 16; /* # of sequential requests treated as one
Linus Torvalds1da177e2005-04-16 15:20:36 -070024 by the above parameters. For throughput. */
25
Linus Torvalds1da177e2005-04-16 15:20:36 -070026struct deadline_data {
27 /*
28 * run time data
29 */
30
31 /*
32 * requests (deadline_rq s) are present on both sort_list and fifo_list
33 */
34 struct rb_root sort_list[2];
35 struct list_head fifo_list[2];
Aaron Carroll4fb72f72008-08-14 18:17:14 +100036
Linus Torvalds1da177e2005-04-16 15:20:36 -070037 /*
38 * next in sort order. read, write or both are NULL
39 */
Jens Axboe8840faa2006-07-13 12:36:41 +020040 struct request *next_rq[2];
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 unsigned int batching; /* number of sequential requests made */
Linus Torvalds1da177e2005-04-16 15:20:36 -070042 unsigned int starved; /* times reads have starved writes */
43
44 /*
45 * settings that change how the i/o scheduler behaves
46 */
47 int fifo_expire[2];
48 int fifo_batch;
49 int writes_starved;
50 int front_merges;
Linus Torvalds1da177e2005-04-16 15:20:36 -070051};
52
Jens Axboe8840faa2006-07-13 12:36:41 +020053static void deadline_move_request(struct deadline_data *, struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070054
Aaron Carroll4fb72f72008-08-14 18:17:14 +100055static inline struct rb_root *
56deadline_rb_root(struct deadline_data *dd, struct request *rq)
57{
58 return &dd->sort_list[rq_data_dir(rq)];
59}
Linus Torvalds1da177e2005-04-16 15:20:36 -070060
Aaron Carroll5d1a5362007-10-30 10:40:12 +010061/*
62 * get the request after `rq' in sector-sorted order
63 */
64static inline struct request *
65deadline_latter_request(struct request *rq)
66{
67 struct rb_node *node = rb_next(&rq->rb_node);
68
69 if (node)
70 return rb_entry_rq(node);
71
72 return NULL;
73}
74
Linus Torvalds1da177e2005-04-16 15:20:36 -070075static void
Jens Axboe8840faa2006-07-13 12:36:41 +020076deadline_add_rq_rb(struct deadline_data *dd, struct request *rq)
Linus Torvalds1da177e2005-04-16 15:20:36 -070077{
Aaron Carroll4fb72f72008-08-14 18:17:14 +100078 struct rb_root *root = deadline_rb_root(dd, rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -070079
Jeff Moyer796d5112011-06-02 21:19:05 +020080 elv_rb_add(root, rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -070081}
82
83static inline void
Jens Axboe8840faa2006-07-13 12:36:41 +020084deadline_del_rq_rb(struct deadline_data *dd, struct request *rq)
Linus Torvalds1da177e2005-04-16 15:20:36 -070085{
Jens Axboeb8aca352006-07-13 12:34:24 +020086 const int data_dir = rq_data_dir(rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -070087
Aaron Carroll5d1a5362007-10-30 10:40:12 +010088 if (dd->next_rq[data_dir] == rq)
89 dd->next_rq[data_dir] = deadline_latter_request(rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -070090
Aaron Carroll4fb72f72008-08-14 18:17:14 +100091 elv_rb_del(deadline_rb_root(dd, rq), rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -070092}
93
94/*
Jens Axboe8840faa2006-07-13 12:36:41 +020095 * add rq to rbtree and fifo
Linus Torvalds1da177e2005-04-16 15:20:36 -070096 */
Jens Axboeb4878f22005-10-20 16:42:29 +020097static void
Linus Torvalds1da177e2005-04-16 15:20:36 -070098deadline_add_request(struct request_queue *q, struct request *rq)
99{
100 struct deadline_data *dd = q->elevator->elevator_data;
Jens Axboe8840faa2006-07-13 12:36:41 +0200101 const int data_dir = rq_data_dir(rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102
Jens Axboe8840faa2006-07-13 12:36:41 +0200103 deadline_add_rq_rb(dd, rq);
Jens Axboe98170642006-07-28 09:23:08 +0200104
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105 /*
Aaron Carroll4fb72f72008-08-14 18:17:14 +1000106 * set expire time and add to fifo list
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107 */
Jan Kara8b4922d2014-02-24 16:39:52 +0100108 rq->fifo_time = jiffies + dd->fifo_expire[data_dir];
Jens Axboe8840faa2006-07-13 12:36:41 +0200109 list_add_tail(&rq->queuelist, &dd->fifo_list[data_dir]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110}
111
112/*
Jens Axboe98170642006-07-28 09:23:08 +0200113 * remove rq from rbtree and fifo.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 */
Jens Axboe165125e2007-07-24 09:28:11 +0200115static void deadline_remove_request(struct request_queue *q, struct request *rq)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116{
Jens Axboeb4878f22005-10-20 16:42:29 +0200117 struct deadline_data *dd = q->elevator->elevator_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118
Jens Axboe8840faa2006-07-13 12:36:41 +0200119 rq_fifo_clear(rq);
120 deadline_del_rq_rb(dd, rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121}
122
Christoph Hellwig34fe7c02017-02-08 14:46:48 +0100123static enum elv_merge
Jens Axboe165125e2007-07-24 09:28:11 +0200124deadline_merge(struct request_queue *q, struct request **req, struct bio *bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125{
126 struct deadline_data *dd = q->elevator->elevator_data;
127 struct request *__rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128
129 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 * check for front merge
131 */
132 if (dd->front_merges) {
Kent Overstreetf73a1c72012-09-25 15:05:12 -0700133 sector_t sector = bio_end_sector(bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134
Jens Axboeb8aca352006-07-13 12:34:24 +0200135 __rq = elv_rb_find(&dd->sort_list[bio_data_dir(bio)], sector);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 if (__rq) {
Tejun Heo83096eb2009-05-07 22:24:39 +0900137 BUG_ON(sector != blk_rq_pos(__rq));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138
Tahsin Erdogan72ef7992016-07-07 11:48:22 -0700139 if (elv_bio_merge_ok(__rq, bio)) {
Christoph Hellwig34fe7c02017-02-08 14:46:48 +0100140 *req = __rq;
141 return ELEVATOR_FRONT_MERGE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 }
143 }
144 }
145
146 return ELEVATOR_NO_MERGE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147}
148
Jens Axboe165125e2007-07-24 09:28:11 +0200149static void deadline_merged_request(struct request_queue *q,
Christoph Hellwig34fe7c02017-02-08 14:46:48 +0100150 struct request *req, enum elv_merge type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151{
152 struct deadline_data *dd = q->elevator->elevator_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153
154 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 * if the merge was a front merge, we need to reposition request
156 */
Jens Axboeb8aca352006-07-13 12:34:24 +0200157 if (type == ELEVATOR_FRONT_MERGE) {
Aaron Carroll4fb72f72008-08-14 18:17:14 +1000158 elv_rb_del(deadline_rb_root(dd, req), req);
Jens Axboe8840faa2006-07-13 12:36:41 +0200159 deadline_add_rq_rb(dd, req);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161}
162
163static void
Jens Axboe165125e2007-07-24 09:28:11 +0200164deadline_merged_requests(struct request_queue *q, struct request *req,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 struct request *next)
166{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167 /*
Jens Axboe8840faa2006-07-13 12:36:41 +0200168 * if next expires before rq, assign its expire time to rq
169 * and move into next position (next will be deleted) in fifo
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 */
Jens Axboe8840faa2006-07-13 12:36:41 +0200171 if (!list_empty(&req->queuelist) && !list_empty(&next->queuelist)) {
Jan Kara9828c2c2016-06-28 09:03:59 +0200172 if (time_before((unsigned long)next->fifo_time,
173 (unsigned long)req->fifo_time)) {
Jens Axboe8840faa2006-07-13 12:36:41 +0200174 list_move(&req->queuelist, &next->queuelist);
Jan Kara8b4922d2014-02-24 16:39:52 +0100175 req->fifo_time = next->fifo_time;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176 }
177 }
178
179 /*
180 * kill knowledge of next, this one is a goner
181 */
182 deadline_remove_request(q, next);
183}
184
185/*
186 * move request from sort list to dispatch queue.
187 */
188static inline void
Jens Axboe8840faa2006-07-13 12:36:41 +0200189deadline_move_to_dispatch(struct deadline_data *dd, struct request *rq)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190{
Jens Axboe165125e2007-07-24 09:28:11 +0200191 struct request_queue *q = rq->q;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192
Jens Axboe8840faa2006-07-13 12:36:41 +0200193 deadline_remove_request(q, rq);
194 elv_dispatch_add_tail(q, rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195}
196
197/*
198 * move an entry to dispatch queue
199 */
200static void
Jens Axboe8840faa2006-07-13 12:36:41 +0200201deadline_move_request(struct deadline_data *dd, struct request *rq)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202{
Jens Axboeb8aca352006-07-13 12:34:24 +0200203 const int data_dir = rq_data_dir(rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204
Jens Axboe8840faa2006-07-13 12:36:41 +0200205 dd->next_rq[READ] = NULL;
206 dd->next_rq[WRITE] = NULL;
Aaron Carroll5d1a5362007-10-30 10:40:12 +0100207 dd->next_rq[data_dir] = deadline_latter_request(rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209 /*
210 * take it off the sort and fifo list, move
211 * to dispatch queue
212 */
Jens Axboe8840faa2006-07-13 12:36:41 +0200213 deadline_move_to_dispatch(dd, rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214}
215
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216/*
Aaron Carroll4fb72f72008-08-14 18:17:14 +1000217 * deadline_check_fifo returns 0 if there are no expired requests on the fifo,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 * 1 otherwise. Requires !list_empty(&dd->fifo_list[data_dir])
219 */
220static inline int deadline_check_fifo(struct deadline_data *dd, int ddir)
221{
Jens Axboe8840faa2006-07-13 12:36:41 +0200222 struct request *rq = rq_entry_fifo(dd->fifo_list[ddir].next);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223
224 /*
Jens Axboe8840faa2006-07-13 12:36:41 +0200225 * rq is expired!
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226 */
Jan Kara9828c2c2016-06-28 09:03:59 +0200227 if (time_after_eq(jiffies, (unsigned long)rq->fifo_time))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228 return 1;
229
230 return 0;
231}
232
233/*
234 * deadline_dispatch_requests selects the best request according to
235 * read/write expire, fifo_batch, etc
236 */
Jens Axboe165125e2007-07-24 09:28:11 +0200237static int deadline_dispatch_requests(struct request_queue *q, int force)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238{
Jens Axboeb4878f22005-10-20 16:42:29 +0200239 struct deadline_data *dd = q->elevator->elevator_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 const int reads = !list_empty(&dd->fifo_list[READ]);
241 const int writes = !list_empty(&dd->fifo_list[WRITE]);
Jens Axboe8840faa2006-07-13 12:36:41 +0200242 struct request *rq;
Nikita Danilov4b0dc072005-09-06 15:17:20 -0700243 int data_dir;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244
245 /*
246 * batches are currently reads XOR writes
247 */
Jens Axboe8840faa2006-07-13 12:36:41 +0200248 if (dd->next_rq[WRITE])
249 rq = dd->next_rq[WRITE];
Andrew Morton9d5c1e12005-09-09 13:02:12 -0700250 else
Jens Axboe8840faa2006-07-13 12:36:41 +0200251 rq = dd->next_rq[READ];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252
Aaron Carroll63de4282008-08-14 18:17:13 +1000253 if (rq && dd->batching < dd->fifo_batch)
254 /* we have a next request are still entitled to batch */
255 goto dispatch_request;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256
257 /*
258 * at this point we are not running a batch. select the appropriate
259 * data direction (read / write)
260 */
261
262 if (reads) {
Jens Axboedd67d052006-06-21 09:36:18 +0200263 BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[READ]));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264
265 if (writes && (dd->starved++ >= dd->writes_starved))
266 goto dispatch_writes;
267
268 data_dir = READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269
270 goto dispatch_find_request;
271 }
272
273 /*
274 * there are either no reads or writes have been starved
275 */
276
277 if (writes) {
278dispatch_writes:
Jens Axboedd67d052006-06-21 09:36:18 +0200279 BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[WRITE]));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280
281 dd->starved = 0;
282
283 data_dir = WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284
285 goto dispatch_find_request;
286 }
287
288 return 0;
289
290dispatch_find_request:
291 /*
292 * we are not running a batch, find best request for selected data_dir
293 */
Aaron Carroll6f5d8aa2007-10-30 10:40:13 +0100294 if (deadline_check_fifo(dd, data_dir) || !dd->next_rq[data_dir]) {
295 /*
296 * A deadline has expired, the last request was in the other
297 * direction, or we have run out of higher-sectored requests.
298 * Start again from the request with the earliest expiry time.
299 */
Jens Axboe8840faa2006-07-13 12:36:41 +0200300 rq = rq_entry_fifo(dd->fifo_list[data_dir].next);
Aaron Carroll6f5d8aa2007-10-30 10:40:13 +0100301 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302 /*
303 * The last req was the same dir and we have a next request in
304 * sort order. No expired requests so continue on from here.
305 */
Jens Axboe8840faa2006-07-13 12:36:41 +0200306 rq = dd->next_rq[data_dir];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 }
308
Aaron Carrolldfb3d722007-10-30 10:40:13 +0100309 dd->batching = 0;
310
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311dispatch_request:
312 /*
Jens Axboe8840faa2006-07-13 12:36:41 +0200313 * rq is the selected appropriate request.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314 */
315 dd->batching++;
Jens Axboe8840faa2006-07-13 12:36:41 +0200316 deadline_move_request(dd, rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317
318 return 1;
319}
320
Jens Axboeb374d182008-10-31 10:05:07 +0100321static void deadline_exit_queue(struct elevator_queue *e)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322{
323 struct deadline_data *dd = e->elevator_data;
324
325 BUG_ON(!list_empty(&dd->fifo_list[READ]));
326 BUG_ON(!list_empty(&dd->fifo_list[WRITE]));
327
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328 kfree(dd);
329}
330
331/*
Jens Axboe8840faa2006-07-13 12:36:41 +0200332 * initialize elevator private data (deadline_data).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 */
Jianpeng Mad50235b2013-07-03 13:25:24 +0200334static int deadline_init_queue(struct request_queue *q, struct elevator_type *e)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335{
336 struct deadline_data *dd;
Jianpeng Mad50235b2013-07-03 13:25:24 +0200337 struct elevator_queue *eq;
338
339 eq = elevator_alloc(q, e);
340 if (!eq)
341 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342
Joe Perchesc1b511e2013-08-29 15:21:42 -0700343 dd = kzalloc_node(sizeof(*dd), GFP_KERNEL, q->node);
Jianpeng Mad50235b2013-07-03 13:25:24 +0200344 if (!dd) {
345 kobject_put(&eq->kobj);
Tejun Heob2fab5a2012-03-05 13:14:57 -0800346 return -ENOMEM;
Jianpeng Mad50235b2013-07-03 13:25:24 +0200347 }
348 eq->elevator_data = dd;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 INIT_LIST_HEAD(&dd->fifo_list[READ]);
351 INIT_LIST_HEAD(&dd->fifo_list[WRITE]);
352 dd->sort_list[READ] = RB_ROOT;
353 dd->sort_list[WRITE] = RB_ROOT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354 dd->fifo_expire[READ] = read_expire;
355 dd->fifo_expire[WRITE] = write_expire;
356 dd->writes_starved = writes_starved;
357 dd->front_merges = 1;
358 dd->fifo_batch = fifo_batch;
Tejun Heob2fab5a2012-03-05 13:14:57 -0800359
Jianpeng Mad50235b2013-07-03 13:25:24 +0200360 spin_lock_irq(q->queue_lock);
361 q->elevator = eq;
362 spin_unlock_irq(q->queue_lock);
Tejun Heob2fab5a2012-03-05 13:14:57 -0800363 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364}
365
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366/*
367 * sysfs parts below
368 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369
370static ssize_t
371deadline_var_show(int var, char *page)
372{
373 return sprintf(page, "%d\n", var);
374}
375
376static ssize_t
377deadline_var_store(int *var, const char *page, size_t count)
378{
379 char *p = (char *) page;
380
381 *var = simple_strtol(p, &p, 10);
382 return count;
383}
384
385#define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \
Jens Axboeb374d182008-10-31 10:05:07 +0100386static ssize_t __FUNC(struct elevator_queue *e, char *page) \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387{ \
Al Viro3d1ab402006-03-18 18:35:43 -0500388 struct deadline_data *dd = e->elevator_data; \
389 int __data = __VAR; \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390 if (__CONV) \
391 __data = jiffies_to_msecs(__data); \
392 return deadline_var_show(__data, (page)); \
393}
Al Viroe572ec72006-03-18 22:27:18 -0500394SHOW_FUNCTION(deadline_read_expire_show, dd->fifo_expire[READ], 1);
395SHOW_FUNCTION(deadline_write_expire_show, dd->fifo_expire[WRITE], 1);
396SHOW_FUNCTION(deadline_writes_starved_show, dd->writes_starved, 0);
397SHOW_FUNCTION(deadline_front_merges_show, dd->front_merges, 0);
398SHOW_FUNCTION(deadline_fifo_batch_show, dd->fifo_batch, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399#undef SHOW_FUNCTION
400
401#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \
Jens Axboeb374d182008-10-31 10:05:07 +0100402static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403{ \
Al Viro3d1ab402006-03-18 18:35:43 -0500404 struct deadline_data *dd = e->elevator_data; \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405 int __data; \
406 int ret = deadline_var_store(&__data, (page), count); \
407 if (__data < (MIN)) \
408 __data = (MIN); \
409 else if (__data > (MAX)) \
410 __data = (MAX); \
411 if (__CONV) \
412 *(__PTR) = msecs_to_jiffies(__data); \
413 else \
414 *(__PTR) = __data; \
415 return ret; \
416}
Al Viroe572ec72006-03-18 22:27:18 -0500417STORE_FUNCTION(deadline_read_expire_store, &dd->fifo_expire[READ], 0, INT_MAX, 1);
418STORE_FUNCTION(deadline_write_expire_store, &dd->fifo_expire[WRITE], 0, INT_MAX, 1);
419STORE_FUNCTION(deadline_writes_starved_store, &dd->writes_starved, INT_MIN, INT_MAX, 0);
420STORE_FUNCTION(deadline_front_merges_store, &dd->front_merges, 0, 1, 0);
421STORE_FUNCTION(deadline_fifo_batch_store, &dd->fifo_batch, 0, INT_MAX, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422#undef STORE_FUNCTION
423
Al Viroe572ec72006-03-18 22:27:18 -0500424#define DD_ATTR(name) \
425 __ATTR(name, S_IRUGO|S_IWUSR, deadline_##name##_show, \
426 deadline_##name##_store)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427
Al Viroe572ec72006-03-18 22:27:18 -0500428static struct elv_fs_entry deadline_attrs[] = {
429 DD_ATTR(read_expire),
430 DD_ATTR(write_expire),
431 DD_ATTR(writes_starved),
432 DD_ATTR(front_merges),
433 DD_ATTR(fifo_batch),
434 __ATTR_NULL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435};
436
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437static struct elevator_type iosched_deadline = {
Jens Axboec51ca6c2016-12-10 15:13:59 -0700438 .ops.sq = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439 .elevator_merge_fn = deadline_merge,
440 .elevator_merged_fn = deadline_merged_request,
441 .elevator_merge_req_fn = deadline_merged_requests,
Jens Axboeb4878f22005-10-20 16:42:29 +0200442 .elevator_dispatch_fn = deadline_dispatch_requests,
443 .elevator_add_req_fn = deadline_add_request,
Jens Axboeb8aca352006-07-13 12:34:24 +0200444 .elevator_former_req_fn = elv_rb_former_request,
445 .elevator_latter_req_fn = elv_rb_latter_request,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446 .elevator_init_fn = deadline_init_queue,
447 .elevator_exit_fn = deadline_exit_queue,
448 },
449
Al Viro3d1ab402006-03-18 18:35:43 -0500450 .elevator_attrs = deadline_attrs,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451 .elevator_name = "deadline",
452 .elevator_owner = THIS_MODULE,
453};
454
455static int __init deadline_init(void)
456{
Tejun Heo3d3c2372011-12-14 00:33:42 +0100457 return elv_register(&iosched_deadline);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458}
459
460static void __exit deadline_exit(void)
461{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462 elv_unregister(&iosched_deadline);
463}
464
465module_init(deadline_init);
466module_exit(deadline_exit);
467
468MODULE_AUTHOR("Jens Axboe");
469MODULE_LICENSE("GPL");
470MODULE_DESCRIPTION("deadline IO scheduler");