Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2 | * Block device elevator/IO-scheduler. |
| 3 | * |
| 4 | * Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE |
| 5 | * |
Jens Axboe | 0fe2347 | 2006-09-04 15:41:16 +0200 | [diff] [blame] | 6 | * 30042000 Jens Axboe <axboe@kernel.dk> : |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 7 | * |
| 8 | * Split the elevator a bit so that it is possible to choose a different |
| 9 | * one or even write a new "plug in". There are three pieces: |
| 10 | * - elevator_fn, inserts a new request in the queue list |
| 11 | * - elevator_merge_fn, decides whether a new buffer can be merged with |
| 12 | * an existing request |
| 13 | * - elevator_dequeue_fn, called when a request is taken off the active list |
| 14 | * |
| 15 | * 20082000 Dave Jones <davej@suse.de> : |
| 16 | * Removed tests for max-bomb-segments, which was breaking elvtune |
| 17 | * when run without -bN |
| 18 | * |
| 19 | * Jens: |
| 20 | * - Rework again to work with bio instead of buffer_heads |
| 21 | * - loose bi_dev comparisons, partition handling is right now |
| 22 | * - completely modularize elevator setup and teardown |
| 23 | * |
| 24 | */ |
| 25 | #include <linux/kernel.h> |
| 26 | #include <linux/fs.h> |
| 27 | #include <linux/blkdev.h> |
| 28 | #include <linux/elevator.h> |
| 29 | #include <linux/bio.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 30 | #include <linux/module.h> |
| 31 | #include <linux/slab.h> |
| 32 | #include <linux/init.h> |
| 33 | #include <linux/compiler.h> |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 34 | #include <linux/delay.h> |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 35 | #include <linux/blktrace_api.h> |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 36 | #include <linux/hash.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 37 | |
| 38 | #include <asm/uaccess.h> |
| 39 | |
| 40 | static DEFINE_SPINLOCK(elv_list_lock); |
| 41 | static LIST_HEAD(elv_list); |
| 42 | |
| 43 | /* |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 44 | * Merge hash stuff. |
| 45 | */ |
| 46 | static const int elv_hash_shift = 6; |
| 47 | #define ELV_HASH_BLOCK(sec) ((sec) >> 3) |
Jens Axboe | 4eb166d | 2008-02-01 00:37:27 +0100 | [diff] [blame] | 48 | #define ELV_HASH_FN(sec) \ |
| 49 | (hash_long(ELV_HASH_BLOCK((sec)), elv_hash_shift)) |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 50 | #define ELV_HASH_ENTRIES (1 << elv_hash_shift) |
| 51 | #define rq_hash_key(rq) ((rq)->sector + (rq)->nr_sectors) |
| 52 | #define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash)) |
| 53 | |
| 54 | /* |
Jens Axboe | da77526 | 2006-12-20 11:04:12 +0100 | [diff] [blame] | 55 | * Query io scheduler to see if the current process issuing bio may be |
| 56 | * merged with rq. |
| 57 | */ |
| 58 | static int elv_iosched_allow_merge(struct request *rq, struct bio *bio) |
| 59 | { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 60 | struct request_queue *q = rq->q; |
Jens Axboe | da77526 | 2006-12-20 11:04:12 +0100 | [diff] [blame] | 61 | elevator_t *e = q->elevator; |
| 62 | |
| 63 | if (e->ops->elevator_allow_merge_fn) |
| 64 | return e->ops->elevator_allow_merge_fn(q, rq, bio); |
| 65 | |
| 66 | return 1; |
| 67 | } |
| 68 | |
| 69 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 70 | * can we safely merge with this request? |
| 71 | */ |
| 72 | inline int elv_rq_merge_ok(struct request *rq, struct bio *bio) |
| 73 | { |
| 74 | if (!rq_mergeable(rq)) |
| 75 | return 0; |
| 76 | |
| 77 | /* |
| 78 | * different data direction or already started, don't merge |
| 79 | */ |
| 80 | if (bio_data_dir(bio) != rq_data_dir(rq)) |
| 81 | return 0; |
| 82 | |
| 83 | /* |
Jens Axboe | da77526 | 2006-12-20 11:04:12 +0100 | [diff] [blame] | 84 | * must be same device and not a special request |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 85 | */ |
Jens Axboe | bb4067e | 2006-12-21 21:20:01 +0100 | [diff] [blame] | 86 | if (rq->rq_disk != bio->bi_bdev->bd_disk || rq->special) |
Jens Axboe | da77526 | 2006-12-20 11:04:12 +0100 | [diff] [blame] | 87 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 88 | |
Jens Axboe | da77526 | 2006-12-20 11:04:12 +0100 | [diff] [blame] | 89 | if (!elv_iosched_allow_merge(rq, bio)) |
| 90 | return 0; |
| 91 | |
| 92 | return 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 93 | } |
| 94 | EXPORT_SYMBOL(elv_rq_merge_ok); |
| 95 | |
Coywolf Qi Hunt | 769db45 | 2005-12-28 10:55:49 +0100 | [diff] [blame] | 96 | static inline int elv_try_merge(struct request *__rq, struct bio *bio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 97 | { |
| 98 | int ret = ELEVATOR_NO_MERGE; |
| 99 | |
| 100 | /* |
| 101 | * we can merge and sequence is ok, check if it's possible |
| 102 | */ |
| 103 | if (elv_rq_merge_ok(__rq, bio)) { |
| 104 | if (__rq->sector + __rq->nr_sectors == bio->bi_sector) |
| 105 | ret = ELEVATOR_BACK_MERGE; |
| 106 | else if (__rq->sector - bio_sectors(bio) == bio->bi_sector) |
| 107 | ret = ELEVATOR_FRONT_MERGE; |
| 108 | } |
| 109 | |
| 110 | return ret; |
| 111 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 112 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 113 | static struct elevator_type *elevator_find(const char *name) |
| 114 | { |
Vasily Tarasov | a22b169 | 2006-10-11 09:24:27 +0200 | [diff] [blame] | 115 | struct elevator_type *e; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 116 | |
Matthias Kaehlcke | 70cee26 | 2007-07-10 12:26:24 +0200 | [diff] [blame] | 117 | list_for_each_entry(e, &elv_list, list) { |
Vasily Tarasov | a22b169 | 2006-10-11 09:24:27 +0200 | [diff] [blame] | 118 | if (!strcmp(e->elevator_name, name)) |
| 119 | return e; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 120 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 121 | |
Vasily Tarasov | a22b169 | 2006-10-11 09:24:27 +0200 | [diff] [blame] | 122 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 123 | } |
| 124 | |
| 125 | static void elevator_put(struct elevator_type *e) |
| 126 | { |
| 127 | module_put(e->elevator_owner); |
| 128 | } |
| 129 | |
| 130 | static struct elevator_type *elevator_get(const char *name) |
| 131 | { |
Tejun Heo | 2824bc93 | 2005-10-20 10:56:41 +0200 | [diff] [blame] | 132 | struct elevator_type *e; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 133 | |
Jens Axboe | 2a12dcd | 2007-04-26 14:41:53 +0200 | [diff] [blame] | 134 | spin_lock(&elv_list_lock); |
Tejun Heo | 2824bc93 | 2005-10-20 10:56:41 +0200 | [diff] [blame] | 135 | |
| 136 | e = elevator_find(name); |
Jens Axboe | e164094 | 2008-02-19 10:20:37 +0100 | [diff] [blame] | 137 | if (!e) { |
| 138 | char elv[ELV_NAME_MAX + strlen("-iosched")]; |
| 139 | |
| 140 | spin_unlock(&elv_list_lock); |
| 141 | |
| 142 | if (!strcmp(name, "anticipatory")) |
| 143 | sprintf(elv, "as-iosched"); |
| 144 | else |
| 145 | sprintf(elv, "%s-iosched", name); |
| 146 | |
| 147 | request_module(elv); |
| 148 | spin_lock(&elv_list_lock); |
| 149 | e = elevator_find(name); |
| 150 | } |
| 151 | |
Tejun Heo | 2824bc93 | 2005-10-20 10:56:41 +0200 | [diff] [blame] | 152 | if (e && !try_module_get(e->elevator_owner)) |
| 153 | e = NULL; |
| 154 | |
Jens Axboe | 2a12dcd | 2007-04-26 14:41:53 +0200 | [diff] [blame] | 155 | spin_unlock(&elv_list_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 156 | |
| 157 | return e; |
| 158 | } |
| 159 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 160 | static void *elevator_init_queue(struct request_queue *q, |
| 161 | struct elevator_queue *eq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 162 | { |
Jens Axboe | bb37b94 | 2006-12-01 10:42:33 +0100 | [diff] [blame] | 163 | return eq->ops->elevator_init_fn(q); |
Jens Axboe | bc1c116 | 2006-06-08 08:49:06 +0200 | [diff] [blame] | 164 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 165 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 166 | static void elevator_attach(struct request_queue *q, struct elevator_queue *eq, |
Jens Axboe | bc1c116 | 2006-06-08 08:49:06 +0200 | [diff] [blame] | 167 | void *data) |
| 168 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 169 | q->elevator = eq; |
Jens Axboe | bc1c116 | 2006-06-08 08:49:06 +0200 | [diff] [blame] | 170 | eq->elevator_data = data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 171 | } |
| 172 | |
| 173 | static char chosen_elevator[16]; |
| 174 | |
Nate Diller | 5f00397 | 2006-01-24 10:07:58 +0100 | [diff] [blame] | 175 | static int __init elevator_setup(char *str) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 176 | { |
Chuck Ebbert | 752a3b7 | 2006-01-16 09:47:37 +0100 | [diff] [blame] | 177 | /* |
| 178 | * Be backwards-compatible with previous kernels, so users |
| 179 | * won't get the wrong elevator. |
| 180 | */ |
Nate Diller | 5f00397 | 2006-01-24 10:07:58 +0100 | [diff] [blame] | 181 | if (!strcmp(str, "as")) |
Chuck Ebbert | 752a3b7 | 2006-01-16 09:47:37 +0100 | [diff] [blame] | 182 | strcpy(chosen_elevator, "anticipatory"); |
Zachary Amsden | cff3ba2 | 2005-11-09 13:24:20 +0100 | [diff] [blame] | 183 | else |
Nate Diller | 5f00397 | 2006-01-24 10:07:58 +0100 | [diff] [blame] | 184 | strncpy(chosen_elevator, str, sizeof(chosen_elevator) - 1); |
OGAWA Hirofumi | 9b41046 | 2006-03-31 02:30:33 -0800 | [diff] [blame] | 185 | return 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 186 | } |
| 187 | |
| 188 | __setup("elevator=", elevator_setup); |
| 189 | |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 190 | static struct kobj_type elv_ktype; |
| 191 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 192 | static elevator_t *elevator_alloc(struct request_queue *q, |
| 193 | struct elevator_type *e) |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 194 | { |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 195 | elevator_t *eq; |
| 196 | int i; |
| 197 | |
Christoph Lameter | 94f6030 | 2007-07-17 04:03:29 -0700 | [diff] [blame] | 198 | eq = kmalloc_node(sizeof(elevator_t), GFP_KERNEL | __GFP_ZERO, q->node); |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 199 | if (unlikely(!eq)) |
| 200 | goto err; |
| 201 | |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 202 | eq->ops = &e->ops; |
| 203 | eq->elevator_type = e; |
Greg Kroah-Hartman | f9cb074 | 2007-12-17 23:05:35 -0700 | [diff] [blame] | 204 | kobject_init(&eq->kobj, &elv_ktype); |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 205 | mutex_init(&eq->sysfs_lock); |
| 206 | |
Jens Axboe | b5deef9 | 2006-07-19 23:39:40 +0200 | [diff] [blame] | 207 | eq->hash = kmalloc_node(sizeof(struct hlist_head) * ELV_HASH_ENTRIES, |
| 208 | GFP_KERNEL, q->node); |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 209 | if (!eq->hash) |
| 210 | goto err; |
| 211 | |
| 212 | for (i = 0; i < ELV_HASH_ENTRIES; i++) |
| 213 | INIT_HLIST_HEAD(&eq->hash[i]); |
| 214 | |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 215 | return eq; |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 216 | err: |
| 217 | kfree(eq); |
| 218 | elevator_put(e); |
| 219 | return NULL; |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 220 | } |
| 221 | |
| 222 | static void elevator_release(struct kobject *kobj) |
| 223 | { |
| 224 | elevator_t *e = container_of(kobj, elevator_t, kobj); |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 225 | |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 226 | elevator_put(e->elevator_type); |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 227 | kfree(e->hash); |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 228 | kfree(e); |
| 229 | } |
| 230 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 231 | int elevator_init(struct request_queue *q, char *name) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 232 | { |
| 233 | struct elevator_type *e = NULL; |
| 234 | struct elevator_queue *eq; |
| 235 | int ret = 0; |
Jens Axboe | bc1c116 | 2006-06-08 08:49:06 +0200 | [diff] [blame] | 236 | void *data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 237 | |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 238 | INIT_LIST_HEAD(&q->queue_head); |
| 239 | q->last_merge = NULL; |
| 240 | q->end_sector = 0; |
| 241 | q->boundary_rq = NULL; |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 242 | |
Jens Axboe | 4eb166d | 2008-02-01 00:37:27 +0100 | [diff] [blame] | 243 | if (name) { |
| 244 | e = elevator_get(name); |
| 245 | if (!e) |
| 246 | return -EINVAL; |
| 247 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 248 | |
Jens Axboe | 4eb166d | 2008-02-01 00:37:27 +0100 | [diff] [blame] | 249 | if (!e && *chosen_elevator) { |
| 250 | e = elevator_get(chosen_elevator); |
| 251 | if (!e) |
| 252 | printk(KERN_ERR "I/O scheduler %s not found\n", |
| 253 | chosen_elevator); |
| 254 | } |
Nate Diller | 248d5ca | 2006-01-24 10:09:14 +0100 | [diff] [blame] | 255 | |
Jens Axboe | 4eb166d | 2008-02-01 00:37:27 +0100 | [diff] [blame] | 256 | if (!e) { |
| 257 | e = elevator_get(CONFIG_DEFAULT_IOSCHED); |
| 258 | if (!e) { |
| 259 | printk(KERN_ERR |
| 260 | "Default I/O scheduler not found. " \ |
| 261 | "Using noop.\n"); |
| 262 | e = elevator_get("noop"); |
| 263 | } |
Nate Diller | 5f00397 | 2006-01-24 10:07:58 +0100 | [diff] [blame] | 264 | } |
| 265 | |
Jens Axboe | b5deef9 | 2006-07-19 23:39:40 +0200 | [diff] [blame] | 266 | eq = elevator_alloc(q, e); |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 267 | if (!eq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 268 | return -ENOMEM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 269 | |
Jens Axboe | bc1c116 | 2006-06-08 08:49:06 +0200 | [diff] [blame] | 270 | data = elevator_init_queue(q, eq); |
| 271 | if (!data) { |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 272 | kobject_put(&eq->kobj); |
Jens Axboe | bc1c116 | 2006-06-08 08:49:06 +0200 | [diff] [blame] | 273 | return -ENOMEM; |
| 274 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 275 | |
Jens Axboe | bc1c116 | 2006-06-08 08:49:06 +0200 | [diff] [blame] | 276 | elevator_attach(q, eq, data); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 277 | return ret; |
| 278 | } |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 279 | EXPORT_SYMBOL(elevator_init); |
| 280 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 281 | void elevator_exit(elevator_t *e) |
| 282 | { |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 283 | mutex_lock(&e->sysfs_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 284 | if (e->ops->elevator_exit_fn) |
| 285 | e->ops->elevator_exit_fn(e); |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 286 | e->ops = NULL; |
| 287 | mutex_unlock(&e->sysfs_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 288 | |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 289 | kobject_put(&e->kobj); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 290 | } |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 291 | EXPORT_SYMBOL(elevator_exit); |
| 292 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 293 | static void elv_activate_rq(struct request_queue *q, struct request *rq) |
Jens Axboe | cad9751 | 2007-01-14 22:26:09 +1100 | [diff] [blame] | 294 | { |
| 295 | elevator_t *e = q->elevator; |
| 296 | |
| 297 | if (e->ops->elevator_activate_req_fn) |
| 298 | e->ops->elevator_activate_req_fn(q, rq); |
| 299 | } |
| 300 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 301 | static void elv_deactivate_rq(struct request_queue *q, struct request *rq) |
Jens Axboe | cad9751 | 2007-01-14 22:26:09 +1100 | [diff] [blame] | 302 | { |
| 303 | elevator_t *e = q->elevator; |
| 304 | |
| 305 | if (e->ops->elevator_deactivate_req_fn) |
| 306 | e->ops->elevator_deactivate_req_fn(q, rq); |
| 307 | } |
| 308 | |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 309 | static inline void __elv_rqhash_del(struct request *rq) |
| 310 | { |
| 311 | hlist_del_init(&rq->hash); |
| 312 | } |
| 313 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 314 | static void elv_rqhash_del(struct request_queue *q, struct request *rq) |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 315 | { |
| 316 | if (ELV_ON_HASH(rq)) |
| 317 | __elv_rqhash_del(rq); |
| 318 | } |
| 319 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 320 | static void elv_rqhash_add(struct request_queue *q, struct request *rq) |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 321 | { |
| 322 | elevator_t *e = q->elevator; |
| 323 | |
| 324 | BUG_ON(ELV_ON_HASH(rq)); |
| 325 | hlist_add_head(&rq->hash, &e->hash[ELV_HASH_FN(rq_hash_key(rq))]); |
| 326 | } |
| 327 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 328 | static void elv_rqhash_reposition(struct request_queue *q, struct request *rq) |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 329 | { |
| 330 | __elv_rqhash_del(rq); |
| 331 | elv_rqhash_add(q, rq); |
| 332 | } |
| 333 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 334 | static struct request *elv_rqhash_find(struct request_queue *q, sector_t offset) |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 335 | { |
| 336 | elevator_t *e = q->elevator; |
| 337 | struct hlist_head *hash_list = &e->hash[ELV_HASH_FN(offset)]; |
| 338 | struct hlist_node *entry, *next; |
| 339 | struct request *rq; |
| 340 | |
| 341 | hlist_for_each_entry_safe(rq, entry, next, hash_list, hash) { |
| 342 | BUG_ON(!ELV_ON_HASH(rq)); |
| 343 | |
| 344 | if (unlikely(!rq_mergeable(rq))) { |
| 345 | __elv_rqhash_del(rq); |
| 346 | continue; |
| 347 | } |
| 348 | |
| 349 | if (rq_hash_key(rq) == offset) |
| 350 | return rq; |
| 351 | } |
| 352 | |
| 353 | return NULL; |
| 354 | } |
| 355 | |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 356 | /* |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 357 | * RB-tree support functions for inserting/lookup/removal of requests |
| 358 | * in a sorted RB tree. |
| 359 | */ |
| 360 | struct request *elv_rb_add(struct rb_root *root, struct request *rq) |
| 361 | { |
| 362 | struct rb_node **p = &root->rb_node; |
| 363 | struct rb_node *parent = NULL; |
| 364 | struct request *__rq; |
| 365 | |
| 366 | while (*p) { |
| 367 | parent = *p; |
| 368 | __rq = rb_entry(parent, struct request, rb_node); |
| 369 | |
| 370 | if (rq->sector < __rq->sector) |
| 371 | p = &(*p)->rb_left; |
| 372 | else if (rq->sector > __rq->sector) |
| 373 | p = &(*p)->rb_right; |
| 374 | else |
| 375 | return __rq; |
| 376 | } |
| 377 | |
| 378 | rb_link_node(&rq->rb_node, parent, p); |
| 379 | rb_insert_color(&rq->rb_node, root); |
| 380 | return NULL; |
| 381 | } |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 382 | EXPORT_SYMBOL(elv_rb_add); |
| 383 | |
| 384 | void elv_rb_del(struct rb_root *root, struct request *rq) |
| 385 | { |
| 386 | BUG_ON(RB_EMPTY_NODE(&rq->rb_node)); |
| 387 | rb_erase(&rq->rb_node, root); |
| 388 | RB_CLEAR_NODE(&rq->rb_node); |
| 389 | } |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 390 | EXPORT_SYMBOL(elv_rb_del); |
| 391 | |
| 392 | struct request *elv_rb_find(struct rb_root *root, sector_t sector) |
| 393 | { |
| 394 | struct rb_node *n = root->rb_node; |
| 395 | struct request *rq; |
| 396 | |
| 397 | while (n) { |
| 398 | rq = rb_entry(n, struct request, rb_node); |
| 399 | |
| 400 | if (sector < rq->sector) |
| 401 | n = n->rb_left; |
| 402 | else if (sector > rq->sector) |
| 403 | n = n->rb_right; |
| 404 | else |
| 405 | return rq; |
| 406 | } |
| 407 | |
| 408 | return NULL; |
| 409 | } |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 410 | EXPORT_SYMBOL(elv_rb_find); |
| 411 | |
| 412 | /* |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 413 | * Insert rq into dispatch queue of q. Queue lock must be held on |
Uwe Kleine-König | dbe7f76 | 2007-10-20 01:55:04 +0200 | [diff] [blame] | 414 | * entry. rq is sort instead into the dispatch queue. To be used by |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 415 | * specific elevators. |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 416 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 417 | void elv_dispatch_sort(struct request_queue *q, struct request *rq) |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 418 | { |
| 419 | sector_t boundary; |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 420 | struct list_head *entry; |
Jens Axboe | 4eb166d | 2008-02-01 00:37:27 +0100 | [diff] [blame] | 421 | int stop_flags; |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 422 | |
Tejun Heo | 06b8624 | 2005-10-20 16:46:23 +0200 | [diff] [blame] | 423 | if (q->last_merge == rq) |
| 424 | q->last_merge = NULL; |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 425 | |
| 426 | elv_rqhash_del(q, rq); |
| 427 | |
Tejun Heo | 15853af | 2005-11-10 08:52:05 +0100 | [diff] [blame] | 428 | q->nr_sorted--; |
Tejun Heo | 06b8624 | 2005-10-20 16:46:23 +0200 | [diff] [blame] | 429 | |
Jens Axboe | 1b47f53 | 2005-10-20 16:37:00 +0200 | [diff] [blame] | 430 | boundary = q->end_sector; |
Jens Axboe | 4eb166d | 2008-02-01 00:37:27 +0100 | [diff] [blame] | 431 | stop_flags = REQ_SOFTBARRIER | REQ_HARDBARRIER | REQ_STARTED; |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 432 | list_for_each_prev(entry, &q->queue_head) { |
| 433 | struct request *pos = list_entry_rq(entry); |
| 434 | |
Jens Axboe | 783660b | 2007-01-19 11:27:47 +1100 | [diff] [blame] | 435 | if (rq_data_dir(rq) != rq_data_dir(pos)) |
| 436 | break; |
Jens Axboe | 4eb166d | 2008-02-01 00:37:27 +0100 | [diff] [blame] | 437 | if (pos->cmd_flags & stop_flags) |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 438 | break; |
| 439 | if (rq->sector >= boundary) { |
| 440 | if (pos->sector < boundary) |
| 441 | continue; |
| 442 | } else { |
| 443 | if (pos->sector >= boundary) |
| 444 | break; |
| 445 | } |
| 446 | if (rq->sector >= pos->sector) |
| 447 | break; |
| 448 | } |
| 449 | |
| 450 | list_add(&rq->queuelist, entry); |
| 451 | } |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 452 | EXPORT_SYMBOL(elv_dispatch_sort); |
| 453 | |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 454 | /* |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 455 | * Insert rq into dispatch queue of q. Queue lock must be held on |
| 456 | * entry. rq is added to the back of the dispatch queue. To be used by |
| 457 | * specific elevators. |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 458 | */ |
| 459 | void elv_dispatch_add_tail(struct request_queue *q, struct request *rq) |
| 460 | { |
| 461 | if (q->last_merge == rq) |
| 462 | q->last_merge = NULL; |
| 463 | |
| 464 | elv_rqhash_del(q, rq); |
| 465 | |
| 466 | q->nr_sorted--; |
| 467 | |
| 468 | q->end_sector = rq_end_sector(rq); |
| 469 | q->boundary_rq = rq; |
| 470 | list_add_tail(&rq->queuelist, &q->queue_head); |
| 471 | } |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 472 | EXPORT_SYMBOL(elv_dispatch_add_tail); |
| 473 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 474 | int elv_merge(struct request_queue *q, struct request **req, struct bio *bio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 475 | { |
| 476 | elevator_t *e = q->elevator; |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 477 | struct request *__rq; |
Tejun Heo | 06b8624 | 2005-10-20 16:46:23 +0200 | [diff] [blame] | 478 | int ret; |
| 479 | |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 480 | /* |
| 481 | * First try one-hit cache. |
| 482 | */ |
Tejun Heo | 06b8624 | 2005-10-20 16:46:23 +0200 | [diff] [blame] | 483 | if (q->last_merge) { |
| 484 | ret = elv_try_merge(q->last_merge, bio); |
| 485 | if (ret != ELEVATOR_NO_MERGE) { |
| 486 | *req = q->last_merge; |
| 487 | return ret; |
| 488 | } |
| 489 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 490 | |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 491 | /* |
| 492 | * See if our hash lookup can find a potential backmerge. |
| 493 | */ |
| 494 | __rq = elv_rqhash_find(q, bio->bi_sector); |
| 495 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
| 496 | *req = __rq; |
| 497 | return ELEVATOR_BACK_MERGE; |
| 498 | } |
| 499 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 500 | if (e->ops->elevator_merge_fn) |
| 501 | return e->ops->elevator_merge_fn(q, req, bio); |
| 502 | |
| 503 | return ELEVATOR_NO_MERGE; |
| 504 | } |
| 505 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 506 | void elv_merged_request(struct request_queue *q, struct request *rq, int type) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 507 | { |
| 508 | elevator_t *e = q->elevator; |
| 509 | |
| 510 | if (e->ops->elevator_merged_fn) |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 511 | e->ops->elevator_merged_fn(q, rq, type); |
Tejun Heo | 06b8624 | 2005-10-20 16:46:23 +0200 | [diff] [blame] | 512 | |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 513 | if (type == ELEVATOR_BACK_MERGE) |
| 514 | elv_rqhash_reposition(q, rq); |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 515 | |
Tejun Heo | 06b8624 | 2005-10-20 16:46:23 +0200 | [diff] [blame] | 516 | q->last_merge = rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 517 | } |
| 518 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 519 | void elv_merge_requests(struct request_queue *q, struct request *rq, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 520 | struct request *next) |
| 521 | { |
| 522 | elevator_t *e = q->elevator; |
| 523 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 524 | if (e->ops->elevator_merge_req_fn) |
| 525 | e->ops->elevator_merge_req_fn(q, rq, next); |
Tejun Heo | 06b8624 | 2005-10-20 16:46:23 +0200 | [diff] [blame] | 526 | |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 527 | elv_rqhash_reposition(q, rq); |
| 528 | elv_rqhash_del(q, next); |
| 529 | |
| 530 | q->nr_sorted--; |
Tejun Heo | 06b8624 | 2005-10-20 16:46:23 +0200 | [diff] [blame] | 531 | q->last_merge = rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 532 | } |
| 533 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 534 | void elv_requeue_request(struct request_queue *q, struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 535 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 536 | /* |
| 537 | * it already went through dequeue, we need to decrement the |
| 538 | * in_flight count again |
| 539 | */ |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 540 | if (blk_account_rq(rq)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 541 | q->in_flight--; |
Jens Axboe | cad9751 | 2007-01-14 22:26:09 +1100 | [diff] [blame] | 542 | if (blk_sorted_rq(rq)) |
| 543 | elv_deactivate_rq(q, rq); |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 544 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 545 | |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 546 | rq->cmd_flags &= ~REQ_STARTED; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 547 | |
Tejun Heo | 30e9656 | 2006-02-08 01:01:31 -0800 | [diff] [blame] | 548 | elv_insert(q, rq, ELEVATOR_INSERT_REQUEUE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 549 | } |
| 550 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 551 | static void elv_drain_elevator(struct request_queue *q) |
Tejun Heo | 15853af | 2005-11-10 08:52:05 +0100 | [diff] [blame] | 552 | { |
| 553 | static int printed; |
| 554 | while (q->elevator->ops->elevator_dispatch_fn(q, 1)) |
| 555 | ; |
| 556 | if (q->nr_sorted == 0) |
| 557 | return; |
| 558 | if (printed++ < 10) { |
| 559 | printk(KERN_ERR "%s: forced dispatching is broken " |
| 560 | "(nr_sorted=%u), please report this\n", |
| 561 | q->elevator->elevator_type->elevator_name, q->nr_sorted); |
| 562 | } |
| 563 | } |
| 564 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 565 | void elv_insert(struct request_queue *q, struct request *rq, int where) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 566 | { |
Tejun Heo | 797e7db | 2006-01-06 09:51:03 +0100 | [diff] [blame] | 567 | struct list_head *pos; |
| 568 | unsigned ordseq; |
Jens Axboe | dac07ec | 2006-05-11 08:20:16 +0200 | [diff] [blame] | 569 | int unplug_it = 1; |
Tejun Heo | 797e7db | 2006-01-06 09:51:03 +0100 | [diff] [blame] | 570 | |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 571 | blk_add_trace_rq(q, rq, BLK_TA_INSERT); |
| 572 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 573 | rq->q = q; |
| 574 | |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 575 | switch (where) { |
| 576 | case ELEVATOR_INSERT_FRONT: |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 577 | rq->cmd_flags |= REQ_SOFTBARRIER; |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 578 | |
| 579 | list_add(&rq->queuelist, &q->queue_head); |
| 580 | break; |
| 581 | |
| 582 | case ELEVATOR_INSERT_BACK: |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 583 | rq->cmd_flags |= REQ_SOFTBARRIER; |
Tejun Heo | 15853af | 2005-11-10 08:52:05 +0100 | [diff] [blame] | 584 | elv_drain_elevator(q); |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 585 | list_add_tail(&rq->queuelist, &q->queue_head); |
| 586 | /* |
| 587 | * We kick the queue here for the following reasons. |
| 588 | * - The elevator might have returned NULL previously |
| 589 | * to delay requests and returned them now. As the |
| 590 | * queue wasn't empty before this request, ll_rw_blk |
| 591 | * won't run the queue on return, resulting in hang. |
| 592 | * - Usually, back inserted requests won't be merged |
| 593 | * with anything. There's no point in delaying queue |
| 594 | * processing. |
| 595 | */ |
| 596 | blk_remove_plug(q); |
| 597 | q->request_fn(q); |
| 598 | break; |
| 599 | |
| 600 | case ELEVATOR_INSERT_SORT: |
| 601 | BUG_ON(!blk_fs_request(rq)); |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 602 | rq->cmd_flags |= REQ_SORTED; |
Tejun Heo | 15853af | 2005-11-10 08:52:05 +0100 | [diff] [blame] | 603 | q->nr_sorted++; |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 604 | if (rq_mergeable(rq)) { |
| 605 | elv_rqhash_add(q, rq); |
| 606 | if (!q->last_merge) |
| 607 | q->last_merge = rq; |
| 608 | } |
| 609 | |
Tejun Heo | ca23509 | 2005-11-01 17:23:49 +0900 | [diff] [blame] | 610 | /* |
| 611 | * Some ioscheds (cfq) run q->request_fn directly, so |
| 612 | * rq cannot be accessed after calling |
| 613 | * elevator_add_req_fn. |
| 614 | */ |
| 615 | q->elevator->ops->elevator_add_req_fn(q, rq); |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 616 | break; |
| 617 | |
Tejun Heo | 797e7db | 2006-01-06 09:51:03 +0100 | [diff] [blame] | 618 | case ELEVATOR_INSERT_REQUEUE: |
| 619 | /* |
| 620 | * If ordered flush isn't in progress, we do front |
| 621 | * insertion; otherwise, requests should be requeued |
| 622 | * in ordseq order. |
| 623 | */ |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 624 | rq->cmd_flags |= REQ_SOFTBARRIER; |
Tejun Heo | 797e7db | 2006-01-06 09:51:03 +0100 | [diff] [blame] | 625 | |
Linas Vepstas | 9554317 | 2007-01-23 19:40:54 +0100 | [diff] [blame] | 626 | /* |
| 627 | * Most requeues happen because of a busy condition, |
| 628 | * don't force unplug of the queue for that case. |
| 629 | */ |
| 630 | unplug_it = 0; |
| 631 | |
Tejun Heo | 797e7db | 2006-01-06 09:51:03 +0100 | [diff] [blame] | 632 | if (q->ordseq == 0) { |
| 633 | list_add(&rq->queuelist, &q->queue_head); |
| 634 | break; |
| 635 | } |
| 636 | |
| 637 | ordseq = blk_ordered_req_seq(rq); |
| 638 | |
| 639 | list_for_each(pos, &q->queue_head) { |
| 640 | struct request *pos_rq = list_entry_rq(pos); |
| 641 | if (ordseq <= blk_ordered_req_seq(pos_rq)) |
| 642 | break; |
| 643 | } |
| 644 | |
| 645 | list_add_tail(&rq->queuelist, pos); |
| 646 | break; |
| 647 | |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 648 | default: |
| 649 | printk(KERN_ERR "%s: bad insertion point %d\n", |
| 650 | __FUNCTION__, where); |
| 651 | BUG(); |
| 652 | } |
| 653 | |
Jens Axboe | dac07ec | 2006-05-11 08:20:16 +0200 | [diff] [blame] | 654 | if (unplug_it && blk_queue_plugged(q)) { |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 655 | int nrq = q->rq.count[READ] + q->rq.count[WRITE] |
| 656 | - q->in_flight; |
| 657 | |
| 658 | if (nrq >= q->unplug_thresh) |
| 659 | __generic_unplug_device(q); |
| 660 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 661 | } |
| 662 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 663 | void __elv_add_request(struct request_queue *q, struct request *rq, int where, |
Tejun Heo | 30e9656 | 2006-02-08 01:01:31 -0800 | [diff] [blame] | 664 | int plug) |
| 665 | { |
| 666 | if (q->ordcolor) |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 667 | rq->cmd_flags |= REQ_ORDERED_COLOR; |
Tejun Heo | 30e9656 | 2006-02-08 01:01:31 -0800 | [diff] [blame] | 668 | |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 669 | if (rq->cmd_flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)) { |
Tejun Heo | 30e9656 | 2006-02-08 01:01:31 -0800 | [diff] [blame] | 670 | /* |
| 671 | * toggle ordered color |
| 672 | */ |
| 673 | if (blk_barrier_rq(rq)) |
| 674 | q->ordcolor ^= 1; |
| 675 | |
| 676 | /* |
| 677 | * barriers implicitly indicate back insertion |
| 678 | */ |
| 679 | if (where == ELEVATOR_INSERT_SORT) |
| 680 | where = ELEVATOR_INSERT_BACK; |
| 681 | |
| 682 | /* |
| 683 | * this request is scheduling boundary, update |
| 684 | * end_sector |
| 685 | */ |
| 686 | if (blk_fs_request(rq)) { |
| 687 | q->end_sector = rq_end_sector(rq); |
| 688 | q->boundary_rq = rq; |
| 689 | } |
Jens Axboe | 4eb166d | 2008-02-01 00:37:27 +0100 | [diff] [blame] | 690 | } else if (!(rq->cmd_flags & REQ_ELVPRIV) && |
| 691 | where == ELEVATOR_INSERT_SORT) |
Tejun Heo | 30e9656 | 2006-02-08 01:01:31 -0800 | [diff] [blame] | 692 | where = ELEVATOR_INSERT_BACK; |
| 693 | |
| 694 | if (plug) |
| 695 | blk_plug_device(q); |
| 696 | |
| 697 | elv_insert(q, rq, where); |
| 698 | } |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 699 | EXPORT_SYMBOL(__elv_add_request); |
| 700 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 701 | void elv_add_request(struct request_queue *q, struct request *rq, int where, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 702 | int plug) |
| 703 | { |
| 704 | unsigned long flags; |
| 705 | |
| 706 | spin_lock_irqsave(q->queue_lock, flags); |
| 707 | __elv_add_request(q, rq, where, plug); |
| 708 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 709 | } |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 710 | EXPORT_SYMBOL(elv_add_request); |
| 711 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 712 | static inline struct request *__elv_next_request(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 713 | { |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 714 | struct request *rq; |
| 715 | |
Tejun Heo | 797e7db | 2006-01-06 09:51:03 +0100 | [diff] [blame] | 716 | while (1) { |
| 717 | while (!list_empty(&q->queue_head)) { |
| 718 | rq = list_entry_rq(q->queue_head.next); |
| 719 | if (blk_do_ordered(q, &rq)) |
| 720 | return rq; |
| 721 | } |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 722 | |
Tejun Heo | 797e7db | 2006-01-06 09:51:03 +0100 | [diff] [blame] | 723 | if (!q->elevator->ops->elevator_dispatch_fn(q, 0)) |
| 724 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 725 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 726 | } |
| 727 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 728 | struct request *elv_next_request(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 729 | { |
| 730 | struct request *rq; |
| 731 | int ret; |
| 732 | |
| 733 | while ((rq = __elv_next_request(q)) != NULL) { |
Jens Axboe | bf2de6f | 2007-09-27 13:01:25 +0200 | [diff] [blame] | 734 | /* |
| 735 | * Kill the empty barrier place holder, the driver must |
| 736 | * not ever see it. |
| 737 | */ |
| 738 | if (blk_empty_barrier(rq)) { |
| 739 | end_queued_request(rq, 1); |
| 740 | continue; |
| 741 | } |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 742 | if (!(rq->cmd_flags & REQ_STARTED)) { |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 743 | /* |
| 744 | * This is the first time the device driver |
| 745 | * sees this request (possibly after |
| 746 | * requeueing). Notify IO scheduler. |
| 747 | */ |
Jens Axboe | cad9751 | 2007-01-14 22:26:09 +1100 | [diff] [blame] | 748 | if (blk_sorted_rq(rq)) |
| 749 | elv_activate_rq(q, rq); |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 750 | |
| 751 | /* |
| 752 | * just mark as started even if we don't start |
| 753 | * it, a request that has been delayed should |
| 754 | * not be passed by new incoming requests |
| 755 | */ |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 756 | rq->cmd_flags |= REQ_STARTED; |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 757 | blk_add_trace_rq(q, rq, BLK_TA_ISSUE); |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 758 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 759 | |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 760 | if (!q->boundary_rq || q->boundary_rq == rq) { |
Jens Axboe | 1b47f53 | 2005-10-20 16:37:00 +0200 | [diff] [blame] | 761 | q->end_sector = rq_end_sector(rq); |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 762 | q->boundary_rq = NULL; |
| 763 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 764 | |
James Bottomley | fa0ccd8 | 2008-01-10 11:30:36 -0600 | [diff] [blame] | 765 | if (rq->cmd_flags & REQ_DONTPREP) |
| 766 | break; |
| 767 | |
| 768 | if (q->dma_drain_size && rq->data_len) { |
| 769 | /* |
| 770 | * make sure space for the drain appears we |
| 771 | * know we can do this because max_hw_segments |
| 772 | * has been adjusted to be one fewer than the |
| 773 | * device can handle |
| 774 | */ |
| 775 | rq->nr_phys_segments++; |
| 776 | rq->nr_hw_segments++; |
| 777 | } |
| 778 | |
| 779 | if (!q->prep_rq_fn) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 780 | break; |
| 781 | |
| 782 | ret = q->prep_rq_fn(q, rq); |
| 783 | if (ret == BLKPREP_OK) { |
| 784 | break; |
| 785 | } else if (ret == BLKPREP_DEFER) { |
Tejun Heo | 2e759cd | 2005-04-24 02:04:21 -0500 | [diff] [blame] | 786 | /* |
| 787 | * the request may have been (partially) prepped. |
| 788 | * we need to keep this request in the front to |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 789 | * avoid resource deadlock. REQ_STARTED will |
| 790 | * prevent other fs requests from passing this one. |
Tejun Heo | 2e759cd | 2005-04-24 02:04:21 -0500 | [diff] [blame] | 791 | */ |
James Bottomley | fa0ccd8 | 2008-01-10 11:30:36 -0600 | [diff] [blame] | 792 | if (q->dma_drain_size && rq->data_len && |
| 793 | !(rq->cmd_flags & REQ_DONTPREP)) { |
| 794 | /* |
| 795 | * remove the space for the drain we added |
| 796 | * so that we don't add it again |
| 797 | */ |
| 798 | --rq->nr_phys_segments; |
| 799 | --rq->nr_hw_segments; |
| 800 | } |
| 801 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 802 | rq = NULL; |
| 803 | break; |
| 804 | } else if (ret == BLKPREP_KILL) { |
Jens Axboe | 4aff5e2 | 2006-08-10 08:44:47 +0200 | [diff] [blame] | 805 | rq->cmd_flags |= REQ_QUIET; |
Jens Axboe | a0cd128 | 2007-09-21 10:41:07 +0200 | [diff] [blame] | 806 | end_queued_request(rq, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 807 | } else { |
| 808 | printk(KERN_ERR "%s: bad return=%d\n", __FUNCTION__, |
| 809 | ret); |
| 810 | break; |
| 811 | } |
| 812 | } |
| 813 | |
| 814 | return rq; |
| 815 | } |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 816 | EXPORT_SYMBOL(elv_next_request); |
| 817 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 818 | void elv_dequeue_request(struct request_queue *q, struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 819 | { |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 820 | BUG_ON(list_empty(&rq->queuelist)); |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 821 | BUG_ON(ELV_ON_HASH(rq)); |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 822 | |
| 823 | list_del_init(&rq->queuelist); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 824 | |
| 825 | /* |
| 826 | * the time frame between a request being removed from the lists |
| 827 | * and to it is freed is accounted as io that is in progress at |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 828 | * the driver side. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 829 | */ |
| 830 | if (blk_account_rq(rq)) |
| 831 | q->in_flight++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 832 | } |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 833 | EXPORT_SYMBOL(elv_dequeue_request); |
| 834 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 835 | int elv_queue_empty(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 836 | { |
| 837 | elevator_t *e = q->elevator; |
| 838 | |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 839 | if (!list_empty(&q->queue_head)) |
| 840 | return 0; |
| 841 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 842 | if (e->ops->elevator_queue_empty_fn) |
| 843 | return e->ops->elevator_queue_empty_fn(q); |
| 844 | |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 845 | return 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 846 | } |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 847 | EXPORT_SYMBOL(elv_queue_empty); |
| 848 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 849 | struct request *elv_latter_request(struct request_queue *q, struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 850 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 851 | elevator_t *e = q->elevator; |
| 852 | |
| 853 | if (e->ops->elevator_latter_req_fn) |
| 854 | return e->ops->elevator_latter_req_fn(q, rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 855 | return NULL; |
| 856 | } |
| 857 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 858 | struct request *elv_former_request(struct request_queue *q, struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 859 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 860 | elevator_t *e = q->elevator; |
| 861 | |
| 862 | if (e->ops->elevator_former_req_fn) |
| 863 | return e->ops->elevator_former_req_fn(q, rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 864 | return NULL; |
| 865 | } |
| 866 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 867 | int elv_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 868 | { |
| 869 | elevator_t *e = q->elevator; |
| 870 | |
| 871 | if (e->ops->elevator_set_req_fn) |
Jens Axboe | cb78b28 | 2006-07-28 09:32:57 +0200 | [diff] [blame] | 872 | return e->ops->elevator_set_req_fn(q, rq, gfp_mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 873 | |
| 874 | rq->elevator_private = NULL; |
| 875 | return 0; |
| 876 | } |
| 877 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 878 | void elv_put_request(struct request_queue *q, struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 879 | { |
| 880 | elevator_t *e = q->elevator; |
| 881 | |
| 882 | if (e->ops->elevator_put_req_fn) |
Jens Axboe | bb37b94 | 2006-12-01 10:42:33 +0100 | [diff] [blame] | 883 | e->ops->elevator_put_req_fn(rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 884 | } |
| 885 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 886 | int elv_may_queue(struct request_queue *q, int rw) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 887 | { |
| 888 | elevator_t *e = q->elevator; |
| 889 | |
| 890 | if (e->ops->elevator_may_queue_fn) |
Jens Axboe | cb78b28 | 2006-07-28 09:32:57 +0200 | [diff] [blame] | 891 | return e->ops->elevator_may_queue_fn(q, rw); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 892 | |
| 893 | return ELV_MQUEUE_MAY; |
| 894 | } |
| 895 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 896 | void elv_completed_request(struct request_queue *q, struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 897 | { |
| 898 | elevator_t *e = q->elevator; |
| 899 | |
| 900 | /* |
| 901 | * request is released from the driver, io must be done |
| 902 | */ |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 903 | if (blk_account_rq(rq)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 904 | q->in_flight--; |
Tejun Heo | 1bc691d | 2006-01-12 15:39:26 +0100 | [diff] [blame] | 905 | if (blk_sorted_rq(rq) && e->ops->elevator_completed_req_fn) |
| 906 | e->ops->elevator_completed_req_fn(q, rq); |
| 907 | } |
Tejun Heo | 797e7db | 2006-01-06 09:51:03 +0100 | [diff] [blame] | 908 | |
Tejun Heo | 1bc691d | 2006-01-12 15:39:26 +0100 | [diff] [blame] | 909 | /* |
| 910 | * Check if the queue is waiting for fs requests to be |
| 911 | * drained for flush sequence. |
| 912 | */ |
| 913 | if (unlikely(q->ordseq)) { |
| 914 | struct request *first_rq = list_entry_rq(q->queue_head.next); |
| 915 | if (q->in_flight == 0 && |
Tejun Heo | 797e7db | 2006-01-06 09:51:03 +0100 | [diff] [blame] | 916 | blk_ordered_cur_seq(q) == QUEUE_ORDSEQ_DRAIN && |
| 917 | blk_ordered_req_seq(first_rq) > QUEUE_ORDSEQ_DRAIN) { |
| 918 | blk_ordered_complete_seq(q, QUEUE_ORDSEQ_DRAIN, 0); |
| 919 | q->request_fn(q); |
| 920 | } |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 921 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 922 | } |
| 923 | |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 924 | #define to_elv(atr) container_of((atr), struct elv_fs_entry, attr) |
| 925 | |
| 926 | static ssize_t |
| 927 | elv_attr_show(struct kobject *kobj, struct attribute *attr, char *page) |
| 928 | { |
| 929 | elevator_t *e = container_of(kobj, elevator_t, kobj); |
| 930 | struct elv_fs_entry *entry = to_elv(attr); |
| 931 | ssize_t error; |
| 932 | |
| 933 | if (!entry->show) |
| 934 | return -EIO; |
| 935 | |
| 936 | mutex_lock(&e->sysfs_lock); |
| 937 | error = e->ops ? entry->show(e, page) : -ENOENT; |
| 938 | mutex_unlock(&e->sysfs_lock); |
| 939 | return error; |
| 940 | } |
| 941 | |
| 942 | static ssize_t |
| 943 | elv_attr_store(struct kobject *kobj, struct attribute *attr, |
| 944 | const char *page, size_t length) |
| 945 | { |
| 946 | elevator_t *e = container_of(kobj, elevator_t, kobj); |
| 947 | struct elv_fs_entry *entry = to_elv(attr); |
| 948 | ssize_t error; |
| 949 | |
| 950 | if (!entry->store) |
| 951 | return -EIO; |
| 952 | |
| 953 | mutex_lock(&e->sysfs_lock); |
| 954 | error = e->ops ? entry->store(e, page, length) : -ENOENT; |
| 955 | mutex_unlock(&e->sysfs_lock); |
| 956 | return error; |
| 957 | } |
| 958 | |
| 959 | static struct sysfs_ops elv_sysfs_ops = { |
| 960 | .show = elv_attr_show, |
| 961 | .store = elv_attr_store, |
| 962 | }; |
| 963 | |
| 964 | static struct kobj_type elv_ktype = { |
| 965 | .sysfs_ops = &elv_sysfs_ops, |
| 966 | .release = elevator_release, |
| 967 | }; |
| 968 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 969 | int elv_register_queue(struct request_queue *q) |
| 970 | { |
| 971 | elevator_t *e = q->elevator; |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 972 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 973 | |
Greg Kroah-Hartman | b2d6db5 | 2007-12-17 23:05:35 -0700 | [diff] [blame] | 974 | error = kobject_add(&e->kobj, &q->kobj, "%s", "iosched"); |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 975 | if (!error) { |
Al Viro | e572ec7 | 2006-03-18 22:27:18 -0500 | [diff] [blame] | 976 | struct elv_fs_entry *attr = e->elevator_type->elevator_attrs; |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 977 | if (attr) { |
Al Viro | e572ec7 | 2006-03-18 22:27:18 -0500 | [diff] [blame] | 978 | while (attr->attr.name) { |
| 979 | if (sysfs_create_file(&e->kobj, &attr->attr)) |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 980 | break; |
Al Viro | e572ec7 | 2006-03-18 22:27:18 -0500 | [diff] [blame] | 981 | attr++; |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 982 | } |
| 983 | } |
| 984 | kobject_uevent(&e->kobj, KOBJ_ADD); |
| 985 | } |
| 986 | return error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 987 | } |
| 988 | |
Jens Axboe | bc1c116 | 2006-06-08 08:49:06 +0200 | [diff] [blame] | 989 | static void __elv_unregister_queue(elevator_t *e) |
| 990 | { |
| 991 | kobject_uevent(&e->kobj, KOBJ_REMOVE); |
| 992 | kobject_del(&e->kobj); |
| 993 | } |
| 994 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 995 | void elv_unregister_queue(struct request_queue *q) |
| 996 | { |
Jens Axboe | bc1c116 | 2006-06-08 08:49:06 +0200 | [diff] [blame] | 997 | if (q) |
| 998 | __elv_unregister_queue(q->elevator); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 999 | } |
| 1000 | |
Adrian Bunk | 2fdd82b | 2007-12-12 18:51:56 +0100 | [diff] [blame] | 1001 | void elv_register(struct elevator_type *e) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1002 | { |
Thibaut VARENE | 1ffb96c | 2007-03-15 12:59:19 +0100 | [diff] [blame] | 1003 | char *def = ""; |
Jens Axboe | 2a12dcd | 2007-04-26 14:41:53 +0200 | [diff] [blame] | 1004 | |
| 1005 | spin_lock(&elv_list_lock); |
Eric Sesterhenn | ce52449 | 2006-03-24 18:43:26 +0100 | [diff] [blame] | 1006 | BUG_ON(elevator_find(e->elevator_name)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1007 | list_add_tail(&e->list, &elv_list); |
Jens Axboe | 2a12dcd | 2007-04-26 14:41:53 +0200 | [diff] [blame] | 1008 | spin_unlock(&elv_list_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1009 | |
Nate Diller | 5f00397 | 2006-01-24 10:07:58 +0100 | [diff] [blame] | 1010 | if (!strcmp(e->elevator_name, chosen_elevator) || |
| 1011 | (!*chosen_elevator && |
| 1012 | !strcmp(e->elevator_name, CONFIG_DEFAULT_IOSCHED))) |
Thibaut VARENE | 1ffb96c | 2007-03-15 12:59:19 +0100 | [diff] [blame] | 1013 | def = " (default)"; |
| 1014 | |
Jens Axboe | 4eb166d | 2008-02-01 00:37:27 +0100 | [diff] [blame] | 1015 | printk(KERN_INFO "io scheduler %s registered%s\n", e->elevator_name, |
| 1016 | def); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1017 | } |
| 1018 | EXPORT_SYMBOL_GPL(elv_register); |
| 1019 | |
| 1020 | void elv_unregister(struct elevator_type *e) |
| 1021 | { |
Christoph Hellwig | 83521d3 | 2005-10-30 15:01:39 -0800 | [diff] [blame] | 1022 | struct task_struct *g, *p; |
| 1023 | |
| 1024 | /* |
| 1025 | * Iterate every thread in the process to remove the io contexts. |
| 1026 | */ |
Al Viro | e17a948 | 2006-03-18 13:21:20 -0500 | [diff] [blame] | 1027 | if (e->ops.trim) { |
| 1028 | read_lock(&tasklist_lock); |
| 1029 | do_each_thread(g, p) { |
| 1030 | task_lock(p); |
Oleg Nesterov | 2d8f613 | 2006-08-22 21:22:13 +0400 | [diff] [blame] | 1031 | if (p->io_context) |
| 1032 | e->ops.trim(p->io_context); |
Al Viro | e17a948 | 2006-03-18 13:21:20 -0500 | [diff] [blame] | 1033 | task_unlock(p); |
| 1034 | } while_each_thread(g, p); |
| 1035 | read_unlock(&tasklist_lock); |
| 1036 | } |
Christoph Hellwig | 83521d3 | 2005-10-30 15:01:39 -0800 | [diff] [blame] | 1037 | |
Jens Axboe | 2a12dcd | 2007-04-26 14:41:53 +0200 | [diff] [blame] | 1038 | spin_lock(&elv_list_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1039 | list_del_init(&e->list); |
Jens Axboe | 2a12dcd | 2007-04-26 14:41:53 +0200 | [diff] [blame] | 1040 | spin_unlock(&elv_list_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1041 | } |
| 1042 | EXPORT_SYMBOL_GPL(elv_unregister); |
| 1043 | |
| 1044 | /* |
| 1045 | * switch to new_e io scheduler. be careful not to introduce deadlocks - |
| 1046 | * we don't free the old io scheduler, before we have allocated what we |
| 1047 | * need for the new one. this way we have a chance of going back to the old |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 1048 | * one, if the new one fails init for some reason. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1049 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 1050 | static int elevator_switch(struct request_queue *q, struct elevator_type *new_e) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1051 | { |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 1052 | elevator_t *old_elevator, *e; |
Jens Axboe | bc1c116 | 2006-06-08 08:49:06 +0200 | [diff] [blame] | 1053 | void *data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1054 | |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 1055 | /* |
| 1056 | * Allocate new elevator |
| 1057 | */ |
Jens Axboe | b5deef9 | 2006-07-19 23:39:40 +0200 | [diff] [blame] | 1058 | e = elevator_alloc(q, new_e); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1059 | if (!e) |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 1060 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1061 | |
Jens Axboe | bc1c116 | 2006-06-08 08:49:06 +0200 | [diff] [blame] | 1062 | data = elevator_init_queue(q, e); |
| 1063 | if (!data) { |
| 1064 | kobject_put(&e->kobj); |
| 1065 | return 0; |
| 1066 | } |
| 1067 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1068 | /* |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 1069 | * Turn on BYPASS and drain all requests w/ elevator private data |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1070 | */ |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 1071 | spin_lock_irq(q->queue_lock); |
| 1072 | |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame^] | 1073 | queue_flag_set(QUEUE_FLAG_ELVSWITCH, q); |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 1074 | |
Tejun Heo | 15853af | 2005-11-10 08:52:05 +0100 | [diff] [blame] | 1075 | elv_drain_elevator(q); |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 1076 | |
| 1077 | while (q->rq.elvpriv) { |
Tejun Heo | 407df2a | 2005-11-10 08:48:21 +0100 | [diff] [blame] | 1078 | blk_remove_plug(q); |
| 1079 | q->request_fn(q); |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 1080 | spin_unlock_irq(q->queue_lock); |
Jens Axboe | 64521d1 | 2005-10-28 08:30:39 +0200 | [diff] [blame] | 1081 | msleep(10); |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 1082 | spin_lock_irq(q->queue_lock); |
Tejun Heo | 15853af | 2005-11-10 08:52:05 +0100 | [diff] [blame] | 1083 | elv_drain_elevator(q); |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 1084 | } |
| 1085 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1086 | /* |
Jens Axboe | bc1c116 | 2006-06-08 08:49:06 +0200 | [diff] [blame] | 1087 | * Remember old elevator. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1088 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1089 | old_elevator = q->elevator; |
| 1090 | |
| 1091 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1092 | * attach and start new elevator |
| 1093 | */ |
Jens Axboe | bc1c116 | 2006-06-08 08:49:06 +0200 | [diff] [blame] | 1094 | elevator_attach(q, e, data); |
| 1095 | |
| 1096 | spin_unlock_irq(q->queue_lock); |
| 1097 | |
| 1098 | __elv_unregister_queue(old_elevator); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1099 | |
| 1100 | if (elv_register_queue(q)) |
| 1101 | goto fail_register; |
| 1102 | |
| 1103 | /* |
Tejun Heo | cb98fc8 | 2005-10-28 08:29:39 +0200 | [diff] [blame] | 1104 | * finally exit old elevator and turn off BYPASS. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1105 | */ |
| 1106 | elevator_exit(old_elevator); |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame^] | 1107 | spin_lock_irq(q->queue_lock); |
| 1108 | queue_flag_clear(QUEUE_FLAG_ELVSWITCH, q); |
| 1109 | spin_unlock_irq(q->queue_lock); |
| 1110 | |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 1111 | return 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1112 | |
| 1113 | fail_register: |
| 1114 | /* |
| 1115 | * switch failed, exit the new io scheduler and reattach the old |
| 1116 | * one again (along with re-adding the sysfs dir) |
| 1117 | */ |
| 1118 | elevator_exit(e); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1119 | q->elevator = old_elevator; |
| 1120 | elv_register_queue(q); |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame^] | 1121 | |
| 1122 | spin_lock_irq(q->queue_lock); |
| 1123 | queue_flag_clear(QUEUE_FLAG_ELVSWITCH, q); |
| 1124 | spin_unlock_irq(q->queue_lock); |
| 1125 | |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 1126 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1127 | } |
| 1128 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 1129 | ssize_t elv_iosched_store(struct request_queue *q, const char *name, |
| 1130 | size_t count) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1131 | { |
| 1132 | char elevator_name[ELV_NAME_MAX]; |
Tejun Heo | be56123 | 2005-11-10 08:55:01 +0100 | [diff] [blame] | 1133 | size_t len; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1134 | struct elevator_type *e; |
| 1135 | |
Tejun Heo | be56123 | 2005-11-10 08:55:01 +0100 | [diff] [blame] | 1136 | elevator_name[sizeof(elevator_name) - 1] = '\0'; |
| 1137 | strncpy(elevator_name, name, sizeof(elevator_name) - 1); |
| 1138 | len = strlen(elevator_name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1139 | |
Tejun Heo | be56123 | 2005-11-10 08:55:01 +0100 | [diff] [blame] | 1140 | if (len && elevator_name[len - 1] == '\n') |
| 1141 | elevator_name[len - 1] = '\0'; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1142 | |
| 1143 | e = elevator_get(elevator_name); |
| 1144 | if (!e) { |
| 1145 | printk(KERN_ERR "elevator: type %s not found\n", elevator_name); |
| 1146 | return -EINVAL; |
| 1147 | } |
| 1148 | |
Nate Diller | 2ca7d93 | 2005-10-30 15:02:24 -0800 | [diff] [blame] | 1149 | if (!strcmp(elevator_name, q->elevator->elevator_type->elevator_name)) { |
| 1150 | elevator_put(e); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1151 | return count; |
Nate Diller | 2ca7d93 | 2005-10-30 15:02:24 -0800 | [diff] [blame] | 1152 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1153 | |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 1154 | if (!elevator_switch(q, e)) |
Jens Axboe | 4eb166d | 2008-02-01 00:37:27 +0100 | [diff] [blame] | 1155 | printk(KERN_ERR "elevator: switch to %s failed\n", |
| 1156 | elevator_name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1157 | return count; |
| 1158 | } |
| 1159 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 1160 | ssize_t elv_iosched_show(struct request_queue *q, char *name) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1161 | { |
| 1162 | elevator_t *e = q->elevator; |
| 1163 | struct elevator_type *elv = e->elevator_type; |
Matthias Kaehlcke | 70cee26 | 2007-07-10 12:26:24 +0200 | [diff] [blame] | 1164 | struct elevator_type *__e; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1165 | int len = 0; |
| 1166 | |
Jens Axboe | 2a12dcd | 2007-04-26 14:41:53 +0200 | [diff] [blame] | 1167 | spin_lock(&elv_list_lock); |
Matthias Kaehlcke | 70cee26 | 2007-07-10 12:26:24 +0200 | [diff] [blame] | 1168 | list_for_each_entry(__e, &elv_list, list) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1169 | if (!strcmp(elv->elevator_name, __e->elevator_name)) |
| 1170 | len += sprintf(name+len, "[%s] ", elv->elevator_name); |
| 1171 | else |
| 1172 | len += sprintf(name+len, "%s ", __e->elevator_name); |
| 1173 | } |
Jens Axboe | 2a12dcd | 2007-04-26 14:41:53 +0200 | [diff] [blame] | 1174 | spin_unlock(&elv_list_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1175 | |
| 1176 | len += sprintf(len+name, "\n"); |
| 1177 | return len; |
| 1178 | } |
| 1179 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 1180 | struct request *elv_rb_former_request(struct request_queue *q, |
| 1181 | struct request *rq) |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 1182 | { |
| 1183 | struct rb_node *rbprev = rb_prev(&rq->rb_node); |
| 1184 | |
| 1185 | if (rbprev) |
| 1186 | return rb_entry_rq(rbprev); |
| 1187 | |
| 1188 | return NULL; |
| 1189 | } |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 1190 | EXPORT_SYMBOL(elv_rb_former_request); |
| 1191 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 1192 | struct request *elv_rb_latter_request(struct request_queue *q, |
| 1193 | struct request *rq) |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 1194 | { |
| 1195 | struct rb_node *rbnext = rb_next(&rq->rb_node); |
| 1196 | |
| 1197 | if (rbnext) |
| 1198 | return rb_entry_rq(rbnext); |
| 1199 | |
| 1200 | return NULL; |
| 1201 | } |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 1202 | EXPORT_SYMBOL(elv_rb_latter_request); |