Christoph Hellwig | 3dcf60bc | 2019-04-30 14:42:43 -0400 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3 | * Block device elevator/IO-scheduler. |
| 4 | * |
| 5 | * Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE |
| 6 | * |
Jens Axboe | 0fe2347 | 2006-09-04 15:41:16 +0200 | [diff] [blame] | 7 | * 30042000 Jens Axboe <axboe@kernel.dk> : |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 8 | * |
| 9 | * Split the elevator a bit so that it is possible to choose a different |
| 10 | * one or even write a new "plug in". There are three pieces: |
| 11 | * - elevator_fn, inserts a new request in the queue list |
| 12 | * - elevator_merge_fn, decides whether a new buffer can be merged with |
| 13 | * an existing request |
| 14 | * - elevator_dequeue_fn, called when a request is taken off the active list |
| 15 | * |
| 16 | * 20082000 Dave Jones <davej@suse.de> : |
| 17 | * Removed tests for max-bomb-segments, which was breaking elvtune |
| 18 | * when run without -bN |
| 19 | * |
| 20 | * Jens: |
| 21 | * - Rework again to work with bio instead of buffer_heads |
| 22 | * - loose bi_dev comparisons, partition handling is right now |
| 23 | * - completely modularize elevator setup and teardown |
| 24 | * |
| 25 | */ |
| 26 | #include <linux/kernel.h> |
| 27 | #include <linux/fs.h> |
| 28 | #include <linux/blkdev.h> |
| 29 | #include <linux/elevator.h> |
| 30 | #include <linux/bio.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 31 | #include <linux/module.h> |
| 32 | #include <linux/slab.h> |
| 33 | #include <linux/init.h> |
| 34 | #include <linux/compiler.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> |
Jens Axboe | 0835da6 | 2008-08-26 09:15:47 +0200 | [diff] [blame] | 37 | #include <linux/uaccess.h> |
Lin Ming | c815881 | 2013-03-23 11:42:27 +0800 | [diff] [blame] | 38 | #include <linux/pm_runtime.h> |
Tejun Heo | eea8f41 | 2015-05-22 17:13:17 -0400 | [diff] [blame] | 39 | #include <linux/blk-cgroup.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 40 | |
Li Zefan | 5578213 | 2009-06-09 13:43:05 +0800 | [diff] [blame] | 41 | #include <trace/events/block.h> |
| 42 | |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 43 | #include "blk.h" |
Jens Axboe | bd166ef | 2017-01-17 06:03:22 -0700 | [diff] [blame] | 44 | #include "blk-mq-sched.h" |
Bart Van Assche | bca6b06 | 2018-09-26 14:01:03 -0700 | [diff] [blame] | 45 | #include "blk-pm.h" |
Jan Kara | 8330cdb | 2017-04-19 11:33:27 +0200 | [diff] [blame] | 46 | #include "blk-wbt.h" |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 47 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 48 | static DEFINE_SPINLOCK(elv_list_lock); |
| 49 | static LIST_HEAD(elv_list); |
| 50 | |
| 51 | /* |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 52 | * Merge hash stuff. |
| 53 | */ |
Tejun Heo | 83096eb | 2009-05-07 22:24:39 +0900 | [diff] [blame] | 54 | #define rq_hash_key(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq)) |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 55 | |
| 56 | /* |
Jens Axboe | da77526 | 2006-12-20 11:04:12 +0100 | [diff] [blame] | 57 | * Query io scheduler to see if the current process issuing bio may be |
| 58 | * merged with rq. |
| 59 | */ |
Tahsin Erdogan | 72ef799 | 2016-07-07 11:48:22 -0700 | [diff] [blame] | 60 | static int elv_iosched_allow_bio_merge(struct request *rq, struct bio *bio) |
Jens Axboe | da77526 | 2006-12-20 11:04:12 +0100 | [diff] [blame] | 61 | { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 62 | struct request_queue *q = rq->q; |
Jens Axboe | b374d18 | 2008-10-31 10:05:07 +0100 | [diff] [blame] | 63 | struct elevator_queue *e = q->elevator; |
Jens Axboe | da77526 | 2006-12-20 11:04:12 +0100 | [diff] [blame] | 64 | |
Jens Axboe | f9cd4bf | 2018-11-01 16:41:41 -0600 | [diff] [blame] | 65 | if (e->type->ops.allow_merge) |
| 66 | return e->type->ops.allow_merge(q, rq, bio); |
Jens Axboe | da77526 | 2006-12-20 11:04:12 +0100 | [diff] [blame] | 67 | |
| 68 | return 1; |
| 69 | } |
| 70 | |
| 71 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 72 | * can we safely merge with this request? |
| 73 | */ |
Tahsin Erdogan | 72ef799 | 2016-07-07 11:48:22 -0700 | [diff] [blame] | 74 | bool elv_bio_merge_ok(struct request *rq, struct bio *bio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 75 | { |
Tejun Heo | 050c8ea | 2012-02-08 09:19:38 +0100 | [diff] [blame] | 76 | if (!blk_rq_merge_ok(rq, bio)) |
Tahsin Erdogan | 72ef799 | 2016-07-07 11:48:22 -0700 | [diff] [blame] | 77 | return false; |
Martin K. Petersen | 7ba1ba1 | 2008-06-30 20:04:41 +0200 | [diff] [blame] | 78 | |
Tahsin Erdogan | 72ef799 | 2016-07-07 11:48:22 -0700 | [diff] [blame] | 79 | if (!elv_iosched_allow_bio_merge(rq, bio)) |
| 80 | return false; |
Jens Axboe | da77526 | 2006-12-20 11:04:12 +0100 | [diff] [blame] | 81 | |
Tahsin Erdogan | 72ef799 | 2016-07-07 11:48:22 -0700 | [diff] [blame] | 82 | return true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 83 | } |
Tahsin Erdogan | 72ef799 | 2016-07-07 11:48:22 -0700 | [diff] [blame] | 84 | EXPORT_SYMBOL(elv_bio_merge_ok); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 85 | |
Damien Le Moal | 68c43f1 | 2019-09-05 18:51:31 +0900 | [diff] [blame] | 86 | static inline bool elv_support_features(unsigned int elv_features, |
| 87 | unsigned int required_features) |
Jens Axboe | 8ac0d9a | 2017-10-25 12:35:02 -0600 | [diff] [blame] | 88 | { |
Damien Le Moal | 68c43f1 | 2019-09-05 18:51:31 +0900 | [diff] [blame] | 89 | return (required_features & elv_features) == required_features; |
| 90 | } |
| 91 | |
| 92 | /** |
| 93 | * elevator_match - Test an elevator name and features |
| 94 | * @e: Scheduler to test |
| 95 | * @name: Elevator name to test |
| 96 | * @required_features: Features that the elevator must provide |
| 97 | * |
| 98 | * Return true is the elevator @e name matches @name and if @e provides all the |
| 99 | * the feratures spcified by @required_features. |
| 100 | */ |
| 101 | static bool elevator_match(const struct elevator_type *e, const char *name, |
| 102 | unsigned int required_features) |
| 103 | { |
| 104 | if (!elv_support_features(e->elevator_features, required_features)) |
| 105 | return false; |
Jens Axboe | 8ac0d9a | 2017-10-25 12:35:02 -0600 | [diff] [blame] | 106 | if (!strcmp(e->elevator_name, name)) |
| 107 | return true; |
| 108 | if (e->elevator_alias && !strcmp(e->elevator_alias, name)) |
| 109 | return true; |
| 110 | |
| 111 | return false; |
| 112 | } |
| 113 | |
Damien Le Moal | 68c43f1 | 2019-09-05 18:51:31 +0900 | [diff] [blame] | 114 | /** |
| 115 | * elevator_find - Find an elevator |
| 116 | * @name: Name of the elevator to find |
| 117 | * @required_features: Features that the elevator must provide |
| 118 | * |
| 119 | * Return the first registered scheduler with name @name and supporting the |
| 120 | * features @required_features and NULL otherwise. |
Jens Axboe | 2527d99 | 2017-10-25 12:33:42 -0600 | [diff] [blame] | 121 | */ |
Damien Le Moal | 68c43f1 | 2019-09-05 18:51:31 +0900 | [diff] [blame] | 122 | static struct elevator_type *elevator_find(const char *name, |
| 123 | unsigned int required_features) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 124 | { |
Vasily Tarasov | a22b169 | 2006-10-11 09:24:27 +0200 | [diff] [blame] | 125 | struct elevator_type *e; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | |
Matthias Kaehlcke | 70cee26 | 2007-07-10 12:26:24 +0200 | [diff] [blame] | 127 | list_for_each_entry(e, &elv_list, list) { |
Damien Le Moal | 68c43f1 | 2019-09-05 18:51:31 +0900 | [diff] [blame] | 128 | if (elevator_match(e, name, required_features)) |
Vasily Tarasov | a22b169 | 2006-10-11 09:24:27 +0200 | [diff] [blame] | 129 | return e; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 130 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 131 | |
Vasily Tarasov | a22b169 | 2006-10-11 09:24:27 +0200 | [diff] [blame] | 132 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 133 | } |
| 134 | |
| 135 | static void elevator_put(struct elevator_type *e) |
| 136 | { |
| 137 | module_put(e->elevator_owner); |
| 138 | } |
| 139 | |
Jens Axboe | 2527d99 | 2017-10-25 12:33:42 -0600 | [diff] [blame] | 140 | static struct elevator_type *elevator_get(struct request_queue *q, |
| 141 | const char *name, bool try_loading) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 142 | { |
Tejun Heo | 2824bc93 | 2005-10-20 10:56:41 +0200 | [diff] [blame] | 143 | struct elevator_type *e; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 144 | |
Jens Axboe | 2a12dcd | 2007-04-26 14:41:53 +0200 | [diff] [blame] | 145 | spin_lock(&elv_list_lock); |
Tejun Heo | 2824bc93 | 2005-10-20 10:56:41 +0200 | [diff] [blame] | 146 | |
Damien Le Moal | 68c43f1 | 2019-09-05 18:51:31 +0900 | [diff] [blame] | 147 | e = elevator_find(name, q->required_elevator_features); |
Tejun Heo | 21c3c5d | 2013-01-22 16:48:03 -0800 | [diff] [blame] | 148 | if (!e && try_loading) { |
Jens Axboe | e164094 | 2008-02-19 10:20:37 +0100 | [diff] [blame] | 149 | spin_unlock(&elv_list_lock); |
Kees Cook | 490b94b | 2011-05-05 18:02:12 -0600 | [diff] [blame] | 150 | request_module("%s-iosched", name); |
Jens Axboe | e164094 | 2008-02-19 10:20:37 +0100 | [diff] [blame] | 151 | spin_lock(&elv_list_lock); |
Damien Le Moal | 68c43f1 | 2019-09-05 18:51:31 +0900 | [diff] [blame] | 152 | e = elevator_find(name, q->required_elevator_features); |
Jens Axboe | e164094 | 2008-02-19 10:20:37 +0100 | [diff] [blame] | 153 | } |
| 154 | |
Tejun Heo | 2824bc93 | 2005-10-20 10:56:41 +0200 | [diff] [blame] | 155 | if (e && !try_module_get(e->elevator_owner)) |
| 156 | e = NULL; |
| 157 | |
Jens Axboe | 2a12dcd | 2007-04-26 14:41:53 +0200 | [diff] [blame] | 158 | spin_unlock(&elv_list_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 159 | return e; |
| 160 | } |
| 161 | |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 162 | static struct kobj_type elv_ktype; |
| 163 | |
Jianpeng Ma | d50235b | 2013-07-03 13:25:24 +0200 | [diff] [blame] | 164 | struct elevator_queue *elevator_alloc(struct request_queue *q, |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 165 | struct elevator_type *e) |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 166 | { |
Jens Axboe | b374d18 | 2008-10-31 10:05:07 +0100 | [diff] [blame] | 167 | struct elevator_queue *eq; |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 168 | |
Joe Perches | c1b511e | 2013-08-29 15:21:42 -0700 | [diff] [blame] | 169 | eq = kzalloc_node(sizeof(*eq), GFP_KERNEL, q->node); |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 170 | if (unlikely(!eq)) |
Chao Yu | 8406a4d | 2015-04-23 10:47:44 -0600 | [diff] [blame] | 171 | return NULL; |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 172 | |
Tejun Heo | 22f746e | 2011-12-14 00:33:41 +0100 | [diff] [blame] | 173 | eq->type = e; |
Greg Kroah-Hartman | f9cb074 | 2007-12-17 23:05:35 -0700 | [diff] [blame] | 174 | kobject_init(&eq->kobj, &elv_ktype); |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 175 | mutex_init(&eq->sysfs_lock); |
Sasha Levin | 242d98f | 2012-12-17 10:01:27 -0500 | [diff] [blame] | 176 | hash_init(eq->hash); |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 177 | |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 178 | return eq; |
| 179 | } |
Jianpeng Ma | d50235b | 2013-07-03 13:25:24 +0200 | [diff] [blame] | 180 | EXPORT_SYMBOL(elevator_alloc); |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 181 | |
| 182 | static void elevator_release(struct kobject *kobj) |
| 183 | { |
Jens Axboe | b374d18 | 2008-10-31 10:05:07 +0100 | [diff] [blame] | 184 | struct elevator_queue *e; |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 185 | |
Jens Axboe | b374d18 | 2008-10-31 10:05:07 +0100 | [diff] [blame] | 186 | e = container_of(kobj, struct elevator_queue, kobj); |
Tejun Heo | 22f746e | 2011-12-14 00:33:41 +0100 | [diff] [blame] | 187 | elevator_put(e->type); |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 188 | kfree(e); |
| 189 | } |
| 190 | |
Ming Lei | c3e2219 | 2019-06-04 21:08:02 +0800 | [diff] [blame] | 191 | void __elevator_exit(struct request_queue *q, struct elevator_queue *e) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 192 | { |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 193 | mutex_lock(&e->sysfs_lock); |
Jens Axboe | f9cd4bf | 2018-11-01 16:41:41 -0600 | [diff] [blame] | 194 | if (e->type->ops.exit_sched) |
Omar Sandoval | 54d5329 | 2017-04-07 08:52:27 -0600 | [diff] [blame] | 195 | blk_mq_exit_sched(q, e); |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 196 | mutex_unlock(&e->sysfs_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 197 | |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 198 | kobject_put(&e->kobj); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 199 | } |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 200 | |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 201 | static inline void __elv_rqhash_del(struct request *rq) |
| 202 | { |
Sasha Levin | 242d98f | 2012-12-17 10:01:27 -0500 | [diff] [blame] | 203 | hash_del(&rq->hash); |
Christoph Hellwig | e806402 | 2016-10-20 15:12:13 +0200 | [diff] [blame] | 204 | rq->rq_flags &= ~RQF_HASHED; |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 205 | } |
| 206 | |
Jens Axboe | 70b3ea0 | 2016-12-07 08:43:31 -0700 | [diff] [blame] | 207 | void elv_rqhash_del(struct request_queue *q, struct request *rq) |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 208 | { |
| 209 | if (ELV_ON_HASH(rq)) |
| 210 | __elv_rqhash_del(rq); |
| 211 | } |
Jens Axboe | bd166ef | 2017-01-17 06:03:22 -0700 | [diff] [blame] | 212 | EXPORT_SYMBOL_GPL(elv_rqhash_del); |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 213 | |
Jens Axboe | 70b3ea0 | 2016-12-07 08:43:31 -0700 | [diff] [blame] | 214 | void elv_rqhash_add(struct request_queue *q, struct request *rq) |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 215 | { |
Jens Axboe | b374d18 | 2008-10-31 10:05:07 +0100 | [diff] [blame] | 216 | struct elevator_queue *e = q->elevator; |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 217 | |
| 218 | BUG_ON(ELV_ON_HASH(rq)); |
Sasha Levin | 242d98f | 2012-12-17 10:01:27 -0500 | [diff] [blame] | 219 | hash_add(e->hash, &rq->hash, rq_hash_key(rq)); |
Christoph Hellwig | e806402 | 2016-10-20 15:12:13 +0200 | [diff] [blame] | 220 | rq->rq_flags |= RQF_HASHED; |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 221 | } |
Jens Axboe | bd166ef | 2017-01-17 06:03:22 -0700 | [diff] [blame] | 222 | EXPORT_SYMBOL_GPL(elv_rqhash_add); |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 223 | |
Jens Axboe | 70b3ea0 | 2016-12-07 08:43:31 -0700 | [diff] [blame] | 224 | void elv_rqhash_reposition(struct request_queue *q, struct request *rq) |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 225 | { |
| 226 | __elv_rqhash_del(rq); |
| 227 | elv_rqhash_add(q, rq); |
| 228 | } |
| 229 | |
Jens Axboe | 70b3ea0 | 2016-12-07 08:43:31 -0700 | [diff] [blame] | 230 | struct request *elv_rqhash_find(struct request_queue *q, sector_t offset) |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 231 | { |
Jens Axboe | b374d18 | 2008-10-31 10:05:07 +0100 | [diff] [blame] | 232 | struct elevator_queue *e = q->elevator; |
Sasha Levin | b67bfe0 | 2013-02-27 17:06:00 -0800 | [diff] [blame] | 233 | struct hlist_node *next; |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 234 | struct request *rq; |
| 235 | |
Linus Torvalds | ee89f81 | 2013-02-28 12:52:24 -0800 | [diff] [blame] | 236 | hash_for_each_possible_safe(e->hash, rq, next, hash, offset) { |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 237 | BUG_ON(!ELV_ON_HASH(rq)); |
| 238 | |
| 239 | if (unlikely(!rq_mergeable(rq))) { |
| 240 | __elv_rqhash_del(rq); |
| 241 | continue; |
| 242 | } |
| 243 | |
| 244 | if (rq_hash_key(rq) == offset) |
| 245 | return rq; |
| 246 | } |
| 247 | |
| 248 | return NULL; |
| 249 | } |
| 250 | |
Tejun Heo | 8922e16 | 2005-10-20 16:23:44 +0200 | [diff] [blame] | 251 | /* |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 252 | * RB-tree support functions for inserting/lookup/removal of requests |
| 253 | * in a sorted RB tree. |
| 254 | */ |
Jeff Moyer | 796d511 | 2011-06-02 21:19:05 +0200 | [diff] [blame] | 255 | void elv_rb_add(struct rb_root *root, struct request *rq) |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 256 | { |
| 257 | struct rb_node **p = &root->rb_node; |
| 258 | struct rb_node *parent = NULL; |
| 259 | struct request *__rq; |
| 260 | |
| 261 | while (*p) { |
| 262 | parent = *p; |
| 263 | __rq = rb_entry(parent, struct request, rb_node); |
| 264 | |
Tejun Heo | 83096eb | 2009-05-07 22:24:39 +0900 | [diff] [blame] | 265 | if (blk_rq_pos(rq) < blk_rq_pos(__rq)) |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 266 | p = &(*p)->rb_left; |
Jeff Moyer | 796d511 | 2011-06-02 21:19:05 +0200 | [diff] [blame] | 267 | else if (blk_rq_pos(rq) >= blk_rq_pos(__rq)) |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 268 | p = &(*p)->rb_right; |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 269 | } |
| 270 | |
| 271 | rb_link_node(&rq->rb_node, parent, p); |
| 272 | rb_insert_color(&rq->rb_node, root); |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 273 | } |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 274 | EXPORT_SYMBOL(elv_rb_add); |
| 275 | |
| 276 | void elv_rb_del(struct rb_root *root, struct request *rq) |
| 277 | { |
| 278 | BUG_ON(RB_EMPTY_NODE(&rq->rb_node)); |
| 279 | rb_erase(&rq->rb_node, root); |
| 280 | RB_CLEAR_NODE(&rq->rb_node); |
| 281 | } |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 282 | EXPORT_SYMBOL(elv_rb_del); |
| 283 | |
| 284 | struct request *elv_rb_find(struct rb_root *root, sector_t sector) |
| 285 | { |
| 286 | struct rb_node *n = root->rb_node; |
| 287 | struct request *rq; |
| 288 | |
| 289 | while (n) { |
| 290 | rq = rb_entry(n, struct request, rb_node); |
| 291 | |
Tejun Heo | 83096eb | 2009-05-07 22:24:39 +0900 | [diff] [blame] | 292 | if (sector < blk_rq_pos(rq)) |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 293 | n = n->rb_left; |
Tejun Heo | 83096eb | 2009-05-07 22:24:39 +0900 | [diff] [blame] | 294 | else if (sector > blk_rq_pos(rq)) |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 295 | n = n->rb_right; |
| 296 | else |
| 297 | return rq; |
| 298 | } |
| 299 | |
| 300 | return NULL; |
| 301 | } |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 302 | EXPORT_SYMBOL(elv_rb_find); |
| 303 | |
Christoph Hellwig | 34fe7c0 | 2017-02-08 14:46:48 +0100 | [diff] [blame] | 304 | enum elv_merge elv_merge(struct request_queue *q, struct request **req, |
| 305 | struct bio *bio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 306 | { |
Jens Axboe | b374d18 | 2008-10-31 10:05:07 +0100 | [diff] [blame] | 307 | struct elevator_queue *e = q->elevator; |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 308 | struct request *__rq; |
Tejun Heo | 06b8624 | 2005-10-20 16:46:23 +0200 | [diff] [blame] | 309 | |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 310 | /* |
Alan D. Brunelle | 488991e | 2010-01-29 09:04:08 +0100 | [diff] [blame] | 311 | * Levels of merges: |
| 312 | * nomerges: No merges at all attempted |
| 313 | * noxmerges: Only simple one-hit cache try |
| 314 | * merges: All merge tries attempted |
| 315 | */ |
Ming Lei | 7460d38 | 2015-10-20 23:13:55 +0800 | [diff] [blame] | 316 | if (blk_queue_nomerges(q) || !bio_mergeable(bio)) |
Alan D. Brunelle | 488991e | 2010-01-29 09:04:08 +0100 | [diff] [blame] | 317 | return ELEVATOR_NO_MERGE; |
| 318 | |
| 319 | /* |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 320 | * First try one-hit cache. |
| 321 | */ |
Tahsin Erdogan | 72ef799 | 2016-07-07 11:48:22 -0700 | [diff] [blame] | 322 | if (q->last_merge && elv_bio_merge_ok(q->last_merge, bio)) { |
Christoph Hellwig | 34fe7c0 | 2017-02-08 14:46:48 +0100 | [diff] [blame] | 323 | enum elv_merge ret = blk_try_merge(q->last_merge, bio); |
| 324 | |
Tejun Heo | 06b8624 | 2005-10-20 16:46:23 +0200 | [diff] [blame] | 325 | if (ret != ELEVATOR_NO_MERGE) { |
| 326 | *req = q->last_merge; |
| 327 | return ret; |
| 328 | } |
| 329 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 330 | |
Alan D. Brunelle | 488991e | 2010-01-29 09:04:08 +0100 | [diff] [blame] | 331 | if (blk_queue_noxmerges(q)) |
Alan D. Brunelle | ac9fafa | 2008-04-29 14:44:19 +0200 | [diff] [blame] | 332 | return ELEVATOR_NO_MERGE; |
| 333 | |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 334 | /* |
| 335 | * See if our hash lookup can find a potential backmerge. |
| 336 | */ |
Kent Overstreet | 4f024f3 | 2013-10-11 15:44:27 -0700 | [diff] [blame] | 337 | __rq = elv_rqhash_find(q, bio->bi_iter.bi_sector); |
Tahsin Erdogan | 72ef799 | 2016-07-07 11:48:22 -0700 | [diff] [blame] | 338 | if (__rq && elv_bio_merge_ok(__rq, bio)) { |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 339 | *req = __rq; |
| 340 | return ELEVATOR_BACK_MERGE; |
| 341 | } |
| 342 | |
Jens Axboe | f9cd4bf | 2018-11-01 16:41:41 -0600 | [diff] [blame] | 343 | if (e->type->ops.request_merge) |
| 344 | return e->type->ops.request_merge(q, req, bio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 345 | |
| 346 | return ELEVATOR_NO_MERGE; |
| 347 | } |
| 348 | |
Jens Axboe | 5e84ea3 | 2011-03-21 10:14:27 +0100 | [diff] [blame] | 349 | /* |
| 350 | * Attempt to do an insertion back merge. Only check for the case where |
| 351 | * we can append 'rq' to an existing request, so we can throw 'rq' away |
| 352 | * afterwards. |
| 353 | * |
| 354 | * Returns true if we merged, false otherwise |
| 355 | */ |
Jens Axboe | bd166ef | 2017-01-17 06:03:22 -0700 | [diff] [blame] | 356 | bool elv_attempt_insert_merge(struct request_queue *q, struct request *rq) |
Jens Axboe | 5e84ea3 | 2011-03-21 10:14:27 +0100 | [diff] [blame] | 357 | { |
| 358 | struct request *__rq; |
Shaohua Li | bee0393 | 2012-11-09 08:44:27 +0100 | [diff] [blame] | 359 | bool ret; |
Jens Axboe | 5e84ea3 | 2011-03-21 10:14:27 +0100 | [diff] [blame] | 360 | |
| 361 | if (blk_queue_nomerges(q)) |
| 362 | return false; |
| 363 | |
| 364 | /* |
| 365 | * First try one-hit cache. |
| 366 | */ |
| 367 | if (q->last_merge && blk_attempt_req_merge(q, q->last_merge, rq)) |
| 368 | return true; |
| 369 | |
| 370 | if (blk_queue_noxmerges(q)) |
| 371 | return false; |
| 372 | |
Shaohua Li | bee0393 | 2012-11-09 08:44:27 +0100 | [diff] [blame] | 373 | ret = false; |
Jens Axboe | 5e84ea3 | 2011-03-21 10:14:27 +0100 | [diff] [blame] | 374 | /* |
| 375 | * See if our hash lookup can find a potential backmerge. |
| 376 | */ |
Shaohua Li | bee0393 | 2012-11-09 08:44:27 +0100 | [diff] [blame] | 377 | while (1) { |
| 378 | __rq = elv_rqhash_find(q, blk_rq_pos(rq)); |
| 379 | if (!__rq || !blk_attempt_req_merge(q, __rq, rq)) |
| 380 | break; |
Jens Axboe | 5e84ea3 | 2011-03-21 10:14:27 +0100 | [diff] [blame] | 381 | |
Shaohua Li | bee0393 | 2012-11-09 08:44:27 +0100 | [diff] [blame] | 382 | /* The merged request could be merged with others, try again */ |
| 383 | ret = true; |
| 384 | rq = __rq; |
| 385 | } |
| 386 | |
| 387 | return ret; |
Jens Axboe | 5e84ea3 | 2011-03-21 10:14:27 +0100 | [diff] [blame] | 388 | } |
| 389 | |
Christoph Hellwig | 34fe7c0 | 2017-02-08 14:46:48 +0100 | [diff] [blame] | 390 | void elv_merged_request(struct request_queue *q, struct request *rq, |
| 391 | enum elv_merge type) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 392 | { |
Jens Axboe | b374d18 | 2008-10-31 10:05:07 +0100 | [diff] [blame] | 393 | struct elevator_queue *e = q->elevator; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 394 | |
Jens Axboe | f9cd4bf | 2018-11-01 16:41:41 -0600 | [diff] [blame] | 395 | if (e->type->ops.request_merged) |
| 396 | e->type->ops.request_merged(q, rq, type); |
Tejun Heo | 06b8624 | 2005-10-20 16:46:23 +0200 | [diff] [blame] | 397 | |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 398 | if (type == ELEVATOR_BACK_MERGE) |
| 399 | elv_rqhash_reposition(q, rq); |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 400 | |
Tejun Heo | 06b8624 | 2005-10-20 16:46:23 +0200 | [diff] [blame] | 401 | q->last_merge = rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 402 | } |
| 403 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 404 | void elv_merge_requests(struct request_queue *q, struct request *rq, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 405 | struct request *next) |
| 406 | { |
Jens Axboe | b374d18 | 2008-10-31 10:05:07 +0100 | [diff] [blame] | 407 | struct elevator_queue *e = q->elevator; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 408 | |
Jens Axboe | f9cd4bf | 2018-11-01 16:41:41 -0600 | [diff] [blame] | 409 | if (e->type->ops.requests_merged) |
| 410 | e->type->ops.requests_merged(q, rq, next); |
Tejun Heo | 06b8624 | 2005-10-20 16:46:23 +0200 | [diff] [blame] | 411 | |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 412 | elv_rqhash_reposition(q, rq); |
Tejun Heo | 06b8624 | 2005-10-20 16:46:23 +0200 | [diff] [blame] | 413 | q->last_merge = rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 414 | } |
| 415 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 416 | struct request *elv_latter_request(struct request_queue *q, struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 417 | { |
Jens Axboe | b374d18 | 2008-10-31 10:05:07 +0100 | [diff] [blame] | 418 | struct elevator_queue *e = q->elevator; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 419 | |
Jens Axboe | f9cd4bf | 2018-11-01 16:41:41 -0600 | [diff] [blame] | 420 | if (e->type->ops.next_request) |
| 421 | return e->type->ops.next_request(q, rq); |
Jens Axboe | bd166ef | 2017-01-17 06:03:22 -0700 | [diff] [blame] | 422 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 423 | return NULL; |
| 424 | } |
| 425 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 426 | struct request *elv_former_request(struct request_queue *q, struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 427 | { |
Jens Axboe | b374d18 | 2008-10-31 10:05:07 +0100 | [diff] [blame] | 428 | struct elevator_queue *e = q->elevator; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 429 | |
Jens Axboe | f9cd4bf | 2018-11-01 16:41:41 -0600 | [diff] [blame] | 430 | if (e->type->ops.former_request) |
| 431 | return e->type->ops.former_request(q, rq); |
Jens Axboe | a1ce35f | 2018-10-29 10:23:51 -0600 | [diff] [blame] | 432 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 433 | return NULL; |
| 434 | } |
| 435 | |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 436 | #define to_elv(atr) container_of((atr), struct elv_fs_entry, attr) |
| 437 | |
| 438 | static ssize_t |
| 439 | elv_attr_show(struct kobject *kobj, struct attribute *attr, char *page) |
| 440 | { |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 441 | struct elv_fs_entry *entry = to_elv(attr); |
Jens Axboe | b374d18 | 2008-10-31 10:05:07 +0100 | [diff] [blame] | 442 | struct elevator_queue *e; |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 443 | ssize_t error; |
| 444 | |
| 445 | if (!entry->show) |
| 446 | return -EIO; |
| 447 | |
Jens Axboe | b374d18 | 2008-10-31 10:05:07 +0100 | [diff] [blame] | 448 | e = container_of(kobj, struct elevator_queue, kobj); |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 449 | mutex_lock(&e->sysfs_lock); |
Tejun Heo | 22f746e | 2011-12-14 00:33:41 +0100 | [diff] [blame] | 450 | error = e->type ? entry->show(e, page) : -ENOENT; |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 451 | mutex_unlock(&e->sysfs_lock); |
| 452 | return error; |
| 453 | } |
| 454 | |
| 455 | static ssize_t |
| 456 | elv_attr_store(struct kobject *kobj, struct attribute *attr, |
| 457 | const char *page, size_t length) |
| 458 | { |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 459 | struct elv_fs_entry *entry = to_elv(attr); |
Jens Axboe | b374d18 | 2008-10-31 10:05:07 +0100 | [diff] [blame] | 460 | struct elevator_queue *e; |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 461 | ssize_t error; |
| 462 | |
| 463 | if (!entry->store) |
| 464 | return -EIO; |
| 465 | |
Jens Axboe | b374d18 | 2008-10-31 10:05:07 +0100 | [diff] [blame] | 466 | e = container_of(kobj, struct elevator_queue, kobj); |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 467 | mutex_lock(&e->sysfs_lock); |
Tejun Heo | 22f746e | 2011-12-14 00:33:41 +0100 | [diff] [blame] | 468 | error = e->type ? entry->store(e, page, length) : -ENOENT; |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 469 | mutex_unlock(&e->sysfs_lock); |
| 470 | return error; |
| 471 | } |
| 472 | |
Emese Revfy | 52cf25d | 2010-01-19 02:58:23 +0100 | [diff] [blame] | 473 | static const struct sysfs_ops elv_sysfs_ops = { |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 474 | .show = elv_attr_show, |
| 475 | .store = elv_attr_store, |
| 476 | }; |
| 477 | |
| 478 | static struct kobj_type elv_ktype = { |
| 479 | .sysfs_ops = &elv_sysfs_ops, |
| 480 | .release = elevator_release, |
| 481 | }; |
| 482 | |
Ming Lei | cecf5d8 | 2019-08-27 19:01:48 +0800 | [diff] [blame] | 483 | /* |
| 484 | * elv_register_queue is called from either blk_register_queue or |
| 485 | * elevator_switch, elevator switch is prevented from being happen |
| 486 | * in the two paths, so it is safe to not hold q->sysfs_lock. |
| 487 | */ |
| 488 | int elv_register_queue(struct request_queue *q, bool uevent) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 489 | { |
Tejun Heo | 5a5bafd | 2012-03-05 13:14:56 -0800 | [diff] [blame] | 490 | struct elevator_queue *e = q->elevator; |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 491 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 492 | |
Greg Kroah-Hartman | b2d6db5 | 2007-12-17 23:05:35 -0700 | [diff] [blame] | 493 | error = kobject_add(&e->kobj, &q->kobj, "%s", "iosched"); |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 494 | if (!error) { |
Tejun Heo | 22f746e | 2011-12-14 00:33:41 +0100 | [diff] [blame] | 495 | struct elv_fs_entry *attr = e->type->elevator_attrs; |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 496 | if (attr) { |
Al Viro | e572ec7 | 2006-03-18 22:27:18 -0500 | [diff] [blame] | 497 | while (attr->attr.name) { |
| 498 | if (sysfs_create_file(&e->kobj, &attr->attr)) |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 499 | break; |
Al Viro | e572ec7 | 2006-03-18 22:27:18 -0500 | [diff] [blame] | 500 | attr++; |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 501 | } |
| 502 | } |
Ming Lei | cecf5d8 | 2019-08-27 19:01:48 +0800 | [diff] [blame] | 503 | if (uevent) |
| 504 | kobject_uevent(&e->kobj, KOBJ_ADD); |
| 505 | |
Jens Axboe | 430c62f | 2010-10-07 09:35:16 +0200 | [diff] [blame] | 506 | e->registered = 1; |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 507 | } |
| 508 | return error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 509 | } |
Jens Axboe | bc1c116 | 2006-06-08 08:49:06 +0200 | [diff] [blame] | 510 | |
Ming Lei | cecf5d8 | 2019-08-27 19:01:48 +0800 | [diff] [blame] | 511 | /* |
| 512 | * elv_unregister_queue is called from either blk_unregister_queue or |
| 513 | * elevator_switch, elevator switch is prevented from being happen |
| 514 | * in the two paths, so it is safe to not hold q->sysfs_lock. |
| 515 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 516 | void elv_unregister_queue(struct request_queue *q) |
| 517 | { |
Tejun Heo | f8fc877 | 2011-12-14 00:33:40 +0100 | [diff] [blame] | 518 | if (q) { |
| 519 | struct elevator_queue *e = q->elevator; |
| 520 | |
| 521 | kobject_uevent(&e->kobj, KOBJ_REMOVE); |
| 522 | kobject_del(&e->kobj); |
Ming Lei | cecf5d8 | 2019-08-27 19:01:48 +0800 | [diff] [blame] | 523 | |
Tejun Heo | f8fc877 | 2011-12-14 00:33:40 +0100 | [diff] [blame] | 524 | e->registered = 0; |
Jan Kara | 8330cdb | 2017-04-19 11:33:27 +0200 | [diff] [blame] | 525 | /* Re-enable throttling in case elevator disabled it */ |
| 526 | wbt_enable_default(q); |
Tejun Heo | f8fc877 | 2011-12-14 00:33:40 +0100 | [diff] [blame] | 527 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 528 | } |
| 529 | |
Jens Axboe | e567bf7 | 2014-06-22 16:32:48 -0600 | [diff] [blame] | 530 | int elv_register(struct elevator_type *e) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 531 | { |
Tejun Heo | 3d3c237 | 2011-12-14 00:33:42 +0100 | [diff] [blame] | 532 | /* create icq_cache if requested */ |
| 533 | if (e->icq_size) { |
| 534 | if (WARN_ON(e->icq_size < sizeof(struct io_cq)) || |
| 535 | WARN_ON(e->icq_align < __alignof__(struct io_cq))) |
| 536 | return -EINVAL; |
| 537 | |
| 538 | snprintf(e->icq_cache_name, sizeof(e->icq_cache_name), |
| 539 | "%s_io_cq", e->elevator_name); |
| 540 | e->icq_cache = kmem_cache_create(e->icq_cache_name, e->icq_size, |
| 541 | e->icq_align, 0, NULL); |
| 542 | if (!e->icq_cache) |
| 543 | return -ENOMEM; |
| 544 | } |
| 545 | |
| 546 | /* register, don't allow duplicate names */ |
Jens Axboe | 2a12dcd | 2007-04-26 14:41:53 +0200 | [diff] [blame] | 547 | spin_lock(&elv_list_lock); |
Damien Le Moal | 68c43f1 | 2019-09-05 18:51:31 +0900 | [diff] [blame] | 548 | if (elevator_find(e->elevator_name, 0)) { |
Tejun Heo | 3d3c237 | 2011-12-14 00:33:42 +0100 | [diff] [blame] | 549 | spin_unlock(&elv_list_lock); |
Chengguang Xu | 62d2a19 | 2018-08-28 07:31:11 +0800 | [diff] [blame] | 550 | kmem_cache_destroy(e->icq_cache); |
Tejun Heo | 3d3c237 | 2011-12-14 00:33:42 +0100 | [diff] [blame] | 551 | return -EBUSY; |
| 552 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 553 | list_add_tail(&e->list, &elv_list); |
Jens Axboe | 2a12dcd | 2007-04-26 14:41:53 +0200 | [diff] [blame] | 554 | spin_unlock(&elv_list_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 555 | |
Hisao Tanabe | d0b0a81 | 2019-04-08 00:27:42 +0900 | [diff] [blame] | 556 | printk(KERN_INFO "io scheduler %s registered\n", e->elevator_name); |
| 557 | |
Tejun Heo | 3d3c237 | 2011-12-14 00:33:42 +0100 | [diff] [blame] | 558 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 559 | } |
| 560 | EXPORT_SYMBOL_GPL(elv_register); |
| 561 | |
| 562 | void elv_unregister(struct elevator_type *e) |
| 563 | { |
Tejun Heo | 3d3c237 | 2011-12-14 00:33:42 +0100 | [diff] [blame] | 564 | /* unregister */ |
Jens Axboe | 2a12dcd | 2007-04-26 14:41:53 +0200 | [diff] [blame] | 565 | spin_lock(&elv_list_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 566 | list_del_init(&e->list); |
Jens Axboe | 2a12dcd | 2007-04-26 14:41:53 +0200 | [diff] [blame] | 567 | spin_unlock(&elv_list_lock); |
Tejun Heo | 3d3c237 | 2011-12-14 00:33:42 +0100 | [diff] [blame] | 568 | |
| 569 | /* |
| 570 | * Destroy icq_cache if it exists. icq's are RCU managed. Make |
| 571 | * sure all RCU operations are complete before proceeding. |
| 572 | */ |
| 573 | if (e->icq_cache) { |
| 574 | rcu_barrier(); |
| 575 | kmem_cache_destroy(e->icq_cache); |
| 576 | e->icq_cache = NULL; |
| 577 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 578 | } |
| 579 | EXPORT_SYMBOL_GPL(elv_unregister); |
| 580 | |
Jianchao Wang | d48ece2 | 2018-08-21 15:15:03 +0800 | [diff] [blame] | 581 | int elevator_switch_mq(struct request_queue *q, |
Omar Sandoval | 54d5329 | 2017-04-07 08:52:27 -0600 | [diff] [blame] | 582 | struct elevator_type *new_e) |
| 583 | { |
| 584 | int ret; |
| 585 | |
Bart Van Assche | 14a2349 | 2018-01-17 11:48:09 -0800 | [diff] [blame] | 586 | lockdep_assert_held(&q->sysfs_lock); |
| 587 | |
Omar Sandoval | 54d5329 | 2017-04-07 08:52:27 -0600 | [diff] [blame] | 588 | if (q->elevator) { |
Ming Lei | b89f625 | 2019-09-23 23:12:09 +0800 | [diff] [blame] | 589 | if (q->elevator->registered) |
Omar Sandoval | 54d5329 | 2017-04-07 08:52:27 -0600 | [diff] [blame] | 590 | elv_unregister_queue(q); |
Ming Lei | cecf5d8 | 2019-08-27 19:01:48 +0800 | [diff] [blame] | 591 | |
Omar Sandoval | 54d5329 | 2017-04-07 08:52:27 -0600 | [diff] [blame] | 592 | ioc_clear_queue(q); |
| 593 | elevator_exit(q, q->elevator); |
| 594 | } |
| 595 | |
| 596 | ret = blk_mq_init_sched(q, new_e); |
| 597 | if (ret) |
| 598 | goto out; |
| 599 | |
| 600 | if (new_e) { |
Ming Lei | cecf5d8 | 2019-08-27 19:01:48 +0800 | [diff] [blame] | 601 | ret = elv_register_queue(q, true); |
Omar Sandoval | 54d5329 | 2017-04-07 08:52:27 -0600 | [diff] [blame] | 602 | if (ret) { |
| 603 | elevator_exit(q, q->elevator); |
| 604 | goto out; |
| 605 | } |
| 606 | } |
| 607 | |
| 608 | if (new_e) |
| 609 | blk_add_trace_msg(q, "elv switch: %s", new_e->elevator_name); |
| 610 | else |
| 611 | blk_add_trace_msg(q, "elv switch: none"); |
| 612 | |
| 613 | out: |
Omar Sandoval | 54d5329 | 2017-04-07 08:52:27 -0600 | [diff] [blame] | 614 | return ret; |
Omar Sandoval | 54d5329 | 2017-04-07 08:52:27 -0600 | [diff] [blame] | 615 | } |
| 616 | |
Damien Le Moal | 61db437 | 2019-09-05 18:51:29 +0900 | [diff] [blame] | 617 | static inline bool elv_support_iosched(struct request_queue *q) |
| 618 | { |
Damien Le Moal | 7a7c5e7 | 2019-10-09 07:39:54 +0900 | [diff] [blame] | 619 | if (!q->mq_ops || |
| 620 | (q->tag_set && (q->tag_set->flags & BLK_MQ_F_NO_SCHED))) |
Damien Le Moal | 61db437 | 2019-09-05 18:51:29 +0900 | [diff] [blame] | 621 | return false; |
| 622 | return true; |
| 623 | } |
| 624 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 625 | /* |
Damien Le Moal | a0958ba | 2019-09-05 18:51:32 +0900 | [diff] [blame] | 626 | * For single queue devices, default to using mq-deadline. If we have multiple |
| 627 | * queues or mq-deadline is not available, default to "none". |
| 628 | */ |
| 629 | static struct elevator_type *elevator_get_default(struct request_queue *q) |
| 630 | { |
| 631 | if (q->nr_hw_queues != 1) |
| 632 | return NULL; |
| 633 | |
| 634 | return elevator_get(q, "mq-deadline", false); |
| 635 | } |
| 636 | |
| 637 | /* |
| 638 | * Get the first elevator providing the features required by the request queue. |
| 639 | * Default to "none" if no matching elevator is found. |
| 640 | */ |
| 641 | static struct elevator_type *elevator_get_by_features(struct request_queue *q) |
| 642 | { |
Jens Axboe | a261425 | 2019-09-06 07:02:31 -0600 | [diff] [blame] | 643 | struct elevator_type *e, *found = NULL; |
Damien Le Moal | a0958ba | 2019-09-05 18:51:32 +0900 | [diff] [blame] | 644 | |
| 645 | spin_lock(&elv_list_lock); |
| 646 | |
| 647 | list_for_each_entry(e, &elv_list, list) { |
| 648 | if (elv_support_features(e->elevator_features, |
Jens Axboe | a261425 | 2019-09-06 07:02:31 -0600 | [diff] [blame] | 649 | q->required_elevator_features)) { |
| 650 | found = e; |
Damien Le Moal | a0958ba | 2019-09-05 18:51:32 +0900 | [diff] [blame] | 651 | break; |
Jens Axboe | a261425 | 2019-09-06 07:02:31 -0600 | [diff] [blame] | 652 | } |
Damien Le Moal | a0958ba | 2019-09-05 18:51:32 +0900 | [diff] [blame] | 653 | } |
| 654 | |
Jens Axboe | a261425 | 2019-09-06 07:02:31 -0600 | [diff] [blame] | 655 | if (found && !try_module_get(found->elevator_owner)) |
| 656 | found = NULL; |
Damien Le Moal | a0958ba | 2019-09-05 18:51:32 +0900 | [diff] [blame] | 657 | |
| 658 | spin_unlock(&elv_list_lock); |
Jens Axboe | a261425 | 2019-09-06 07:02:31 -0600 | [diff] [blame] | 659 | return found; |
Damien Le Moal | a0958ba | 2019-09-05 18:51:32 +0900 | [diff] [blame] | 660 | } |
| 661 | |
| 662 | /* |
| 663 | * For a device queue that has no required features, use the default elevator |
| 664 | * settings. Otherwise, use the first elevator available matching the required |
| 665 | * features. If no suitable elevator is find or if the chosen elevator |
| 666 | * initialization fails, fall back to the "none" elevator (no elevator). |
Christoph Hellwig | 131d08e | 2018-05-31 19:11:40 +0200 | [diff] [blame] | 667 | */ |
Damien Le Moal | 954b4a5 | 2019-09-05 18:51:30 +0900 | [diff] [blame] | 668 | void elevator_init_mq(struct request_queue *q) |
Christoph Hellwig | 131d08e | 2018-05-31 19:11:40 +0200 | [diff] [blame] | 669 | { |
| 670 | struct elevator_type *e; |
Damien Le Moal | 954b4a5 | 2019-09-05 18:51:30 +0900 | [diff] [blame] | 671 | int err; |
Christoph Hellwig | 131d08e | 2018-05-31 19:11:40 +0200 | [diff] [blame] | 672 | |
Damien Le Moal | 61db437 | 2019-09-05 18:51:29 +0900 | [diff] [blame] | 673 | if (!elv_support_iosched(q)) |
Damien Le Moal | 954b4a5 | 2019-09-05 18:51:30 +0900 | [diff] [blame] | 674 | return; |
Damien Le Moal | 61db437 | 2019-09-05 18:51:29 +0900 | [diff] [blame] | 675 | |
Ming Lei | c48dac1 | 2019-08-27 19:01:45 +0800 | [diff] [blame] | 676 | WARN_ON_ONCE(test_bit(QUEUE_FLAG_REGISTERED, &q->queue_flags)); |
| 677 | |
Christoph Hellwig | 131d08e | 2018-05-31 19:11:40 +0200 | [diff] [blame] | 678 | if (unlikely(q->elevator)) |
Damien Le Moal | 954b4a5 | 2019-09-05 18:51:30 +0900 | [diff] [blame] | 679 | return; |
Christoph Hellwig | 131d08e | 2018-05-31 19:11:40 +0200 | [diff] [blame] | 680 | |
Damien Le Moal | a0958ba | 2019-09-05 18:51:32 +0900 | [diff] [blame] | 681 | if (!q->required_elevator_features) |
| 682 | e = elevator_get_default(q); |
| 683 | else |
| 684 | e = elevator_get_by_features(q); |
Christoph Hellwig | 131d08e | 2018-05-31 19:11:40 +0200 | [diff] [blame] | 685 | if (!e) |
Damien Le Moal | 954b4a5 | 2019-09-05 18:51:30 +0900 | [diff] [blame] | 686 | return; |
Christoph Hellwig | 131d08e | 2018-05-31 19:11:40 +0200 | [diff] [blame] | 687 | |
Damien Le Moal | 737eb78 | 2019-09-05 18:51:33 +0900 | [diff] [blame] | 688 | blk_mq_freeze_queue(q); |
| 689 | blk_mq_quiesce_queue(q); |
| 690 | |
Christoph Hellwig | 131d08e | 2018-05-31 19:11:40 +0200 | [diff] [blame] | 691 | err = blk_mq_init_sched(q, e); |
Damien Le Moal | 737eb78 | 2019-09-05 18:51:33 +0900 | [diff] [blame] | 692 | |
| 693 | blk_mq_unquiesce_queue(q); |
| 694 | blk_mq_unfreeze_queue(q); |
| 695 | |
Damien Le Moal | 954b4a5 | 2019-09-05 18:51:30 +0900 | [diff] [blame] | 696 | if (err) { |
| 697 | pr_warn("\"%s\" elevator initialization failed, " |
| 698 | "falling back to \"none\"\n", e->elevator_name); |
Christoph Hellwig | 131d08e | 2018-05-31 19:11:40 +0200 | [diff] [blame] | 699 | elevator_put(e); |
Damien Le Moal | 954b4a5 | 2019-09-05 18:51:30 +0900 | [diff] [blame] | 700 | } |
Christoph Hellwig | 131d08e | 2018-05-31 19:11:40 +0200 | [diff] [blame] | 701 | } |
| 702 | |
| 703 | |
| 704 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 705 | * switch to new_e io scheduler. be careful not to introduce deadlocks - |
| 706 | * we don't free the old io scheduler, before we have allocated what we |
| 707 | * 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] | 708 | * one, if the new one fails init for some reason. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 709 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 710 | 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] | 711 | { |
Tejun Heo | e8989fa | 2012-03-05 13:15:20 -0800 | [diff] [blame] | 712 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 713 | |
Bart Van Assche | 14a2349 | 2018-01-17 11:48:09 -0800 | [diff] [blame] | 714 | lockdep_assert_held(&q->sysfs_lock); |
| 715 | |
Jens Axboe | a1ce35f | 2018-10-29 10:23:51 -0600 | [diff] [blame] | 716 | blk_mq_freeze_queue(q); |
| 717 | blk_mq_quiesce_queue(q); |
Jianchao Wang | d48ece2 | 2018-08-21 15:15:03 +0800 | [diff] [blame] | 718 | |
Jens Axboe | a1ce35f | 2018-10-29 10:23:51 -0600 | [diff] [blame] | 719 | err = elevator_switch_mq(q, new_e); |
Jianchao Wang | d48ece2 | 2018-08-21 15:15:03 +0800 | [diff] [blame] | 720 | |
Jens Axboe | a1ce35f | 2018-10-29 10:23:51 -0600 | [diff] [blame] | 721 | blk_mq_unquiesce_queue(q); |
| 722 | blk_mq_unfreeze_queue(q); |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame] | 723 | |
Jens Axboe | 5dd531a | 2010-08-23 13:52:19 +0200 | [diff] [blame] | 724 | return err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 725 | } |
| 726 | |
Jens Axboe | 5dd531a | 2010-08-23 13:52:19 +0200 | [diff] [blame] | 727 | /* |
| 728 | * Switch this queue to the given IO scheduler. |
| 729 | */ |
Tomoki Sekiyama | 7c8a367 | 2013-10-15 16:42:19 -0600 | [diff] [blame] | 730 | static int __elevator_change(struct request_queue *q, const char *name) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 731 | { |
| 732 | char elevator_name[ELV_NAME_MAX]; |
| 733 | struct elevator_type *e; |
| 734 | |
David Jeffery | e9a823f | 2017-08-28 10:52:44 -0600 | [diff] [blame] | 735 | /* Make sure queue is not in the middle of being removed */ |
Ming Lei | 58c898b | 2019-08-27 19:01:47 +0800 | [diff] [blame] | 736 | if (!blk_queue_registered(q)) |
David Jeffery | e9a823f | 2017-08-28 10:52:44 -0600 | [diff] [blame] | 737 | return -ENOENT; |
| 738 | |
Jens Axboe | bd166ef | 2017-01-17 06:03:22 -0700 | [diff] [blame] | 739 | /* |
| 740 | * Special case for mq, turn off scheduling |
| 741 | */ |
Aleksei Zakharov | fbd7212 | 2019-02-11 13:50:37 +0300 | [diff] [blame] | 742 | if (!strncmp(name, "none", 4)) { |
| 743 | if (!q->elevator) |
| 744 | return 0; |
Jens Axboe | bd166ef | 2017-01-17 06:03:22 -0700 | [diff] [blame] | 745 | return elevator_switch(q, NULL); |
Aleksei Zakharov | fbd7212 | 2019-02-11 13:50:37 +0300 | [diff] [blame] | 746 | } |
Martin K. Petersen | cd43e26 | 2009-05-22 17:17:52 -0400 | [diff] [blame] | 747 | |
Li Zefan | ee2e992 | 2008-10-14 08:49:56 +0200 | [diff] [blame] | 748 | strlcpy(elevator_name, name, sizeof(elevator_name)); |
Jens Axboe | 2527d99 | 2017-10-25 12:33:42 -0600 | [diff] [blame] | 749 | e = elevator_get(q, strstrip(elevator_name), true); |
Jens Axboe | 340ff32 | 2017-05-10 07:40:04 -0600 | [diff] [blame] | 750 | if (!e) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 751 | return -EINVAL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 752 | |
Damien Le Moal | 68c43f1 | 2019-09-05 18:51:31 +0900 | [diff] [blame] | 753 | if (q->elevator && |
| 754 | elevator_match(q->elevator->type, elevator_name, 0)) { |
Nate Diller | 2ca7d93 | 2005-10-30 15:02:24 -0800 | [diff] [blame] | 755 | elevator_put(e); |
Jens Axboe | 5dd531a | 2010-08-23 13:52:19 +0200 | [diff] [blame] | 756 | return 0; |
Nate Diller | 2ca7d93 | 2005-10-30 15:02:24 -0800 | [diff] [blame] | 757 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 758 | |
Jens Axboe | 5dd531a | 2010-08-23 13:52:19 +0200 | [diff] [blame] | 759 | return elevator_switch(q, e); |
| 760 | } |
Tomoki Sekiyama | 7c8a367 | 2013-10-15 16:42:19 -0600 | [diff] [blame] | 761 | |
Jens Axboe | 5dd531a | 2010-08-23 13:52:19 +0200 | [diff] [blame] | 762 | ssize_t elv_iosched_store(struct request_queue *q, const char *name, |
| 763 | size_t count) |
| 764 | { |
| 765 | int ret; |
| 766 | |
Jens Axboe | 344e9ff | 2018-11-15 12:22:51 -0700 | [diff] [blame] | 767 | if (!queue_is_mq(q) || !elv_support_iosched(q)) |
Jens Axboe | 5dd531a | 2010-08-23 13:52:19 +0200 | [diff] [blame] | 768 | return count; |
| 769 | |
Tomoki Sekiyama | 7c8a367 | 2013-10-15 16:42:19 -0600 | [diff] [blame] | 770 | ret = __elevator_change(q, name); |
Jens Axboe | 5dd531a | 2010-08-23 13:52:19 +0200 | [diff] [blame] | 771 | if (!ret) |
| 772 | return count; |
| 773 | |
Jens Axboe | 5dd531a | 2010-08-23 13:52:19 +0200 | [diff] [blame] | 774 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 775 | } |
| 776 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 777 | ssize_t elv_iosched_show(struct request_queue *q, char *name) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 778 | { |
Jens Axboe | b374d18 | 2008-10-31 10:05:07 +0100 | [diff] [blame] | 779 | struct elevator_queue *e = q->elevator; |
Jens Axboe | bd166ef | 2017-01-17 06:03:22 -0700 | [diff] [blame] | 780 | struct elevator_type *elv = NULL; |
Matthias Kaehlcke | 70cee26 | 2007-07-10 12:26:24 +0200 | [diff] [blame] | 781 | struct elevator_type *__e; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 782 | int len = 0; |
| 783 | |
Jens Axboe | 344e9ff | 2018-11-15 12:22:51 -0700 | [diff] [blame] | 784 | if (!queue_is_mq(q)) |
Martin K. Petersen | cd43e26 | 2009-05-22 17:17:52 -0400 | [diff] [blame] | 785 | return sprintf(name, "none\n"); |
| 786 | |
Jens Axboe | bd166ef | 2017-01-17 06:03:22 -0700 | [diff] [blame] | 787 | if (!q->elevator) |
| 788 | len += sprintf(name+len, "[none] "); |
| 789 | else |
| 790 | elv = e->type; |
Martin K. Petersen | cd43e26 | 2009-05-22 17:17:52 -0400 | [diff] [blame] | 791 | |
Jens Axboe | 2a12dcd | 2007-04-26 14:41:53 +0200 | [diff] [blame] | 792 | spin_lock(&elv_list_lock); |
Matthias Kaehlcke | 70cee26 | 2007-07-10 12:26:24 +0200 | [diff] [blame] | 793 | list_for_each_entry(__e, &elv_list, list) { |
Damien Le Moal | 68c43f1 | 2019-09-05 18:51:31 +0900 | [diff] [blame] | 794 | if (elv && elevator_match(elv, __e->elevator_name, 0)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 795 | len += sprintf(name+len, "[%s] ", elv->elevator_name); |
Jens Axboe | bd166ef | 2017-01-17 06:03:22 -0700 | [diff] [blame] | 796 | continue; |
| 797 | } |
Damien Le Moal | 68c43f1 | 2019-09-05 18:51:31 +0900 | [diff] [blame] | 798 | if (elv_support_iosched(q) && |
| 799 | elevator_match(__e, __e->elevator_name, |
| 800 | q->required_elevator_features)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 801 | len += sprintf(name+len, "%s ", __e->elevator_name); |
| 802 | } |
Jens Axboe | 2a12dcd | 2007-04-26 14:41:53 +0200 | [diff] [blame] | 803 | spin_unlock(&elv_list_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 804 | |
Jens Axboe | 344e9ff | 2018-11-15 12:22:51 -0700 | [diff] [blame] | 805 | if (q->elevator) |
Jens Axboe | bd166ef | 2017-01-17 06:03:22 -0700 | [diff] [blame] | 806 | len += sprintf(name+len, "none"); |
| 807 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 808 | len += sprintf(len+name, "\n"); |
| 809 | return len; |
| 810 | } |
| 811 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 812 | struct request *elv_rb_former_request(struct request_queue *q, |
| 813 | struct request *rq) |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 814 | { |
| 815 | struct rb_node *rbprev = rb_prev(&rq->rb_node); |
| 816 | |
| 817 | if (rbprev) |
| 818 | return rb_entry_rq(rbprev); |
| 819 | |
| 820 | return NULL; |
| 821 | } |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 822 | EXPORT_SYMBOL(elv_rb_former_request); |
| 823 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 824 | struct request *elv_rb_latter_request(struct request_queue *q, |
| 825 | struct request *rq) |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 826 | { |
| 827 | struct rb_node *rbnext = rb_next(&rq->rb_node); |
| 828 | |
| 829 | if (rbnext) |
| 830 | return rb_entry_rq(rbnext); |
| 831 | |
| 832 | return NULL; |
| 833 | } |
Jens Axboe | 2e662b6 | 2006-07-13 11:55:04 +0200 | [diff] [blame] | 834 | EXPORT_SYMBOL(elv_rb_latter_request); |
Jan Kara | f8db383 | 2019-11-06 11:48:57 +0100 | [diff] [blame] | 835 | |
| 836 | static int __init elevator_setup(char *str) |
| 837 | { |
| 838 | pr_warn("Kernel parameter elevator= does not have any effect anymore.\n" |
| 839 | "Please use sysfs to set IO scheduler for individual devices.\n"); |
| 840 | return 1; |
| 841 | } |
| 842 | |
| 843 | __setup("elevator=", elevator_setup); |