Commit | Line | Data |
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242f9dcb JA |
1 | /* |
2 | * Functions related to generic timeout handling of requests. | |
3 | */ | |
4 | #include <linux/kernel.h> | |
5 | #include <linux/module.h> | |
6 | #include <linux/blkdev.h> | |
581d4e28 | 7 | #include <linux/fault-inject.h> |
242f9dcb JA |
8 | |
9 | #include "blk.h" | |
90415837 | 10 | #include "blk-mq.h" |
242f9dcb | 11 | |
581d4e28 JA |
12 | #ifdef CONFIG_FAIL_IO_TIMEOUT |
13 | ||
14 | static DECLARE_FAULT_ATTR(fail_io_timeout); | |
15 | ||
16 | static int __init setup_fail_io_timeout(char *str) | |
17 | { | |
18 | return setup_fault_attr(&fail_io_timeout, str); | |
19 | } | |
20 | __setup("fail_io_timeout=", setup_fail_io_timeout); | |
21 | ||
22 | int blk_should_fake_timeout(struct request_queue *q) | |
23 | { | |
24 | if (!test_bit(QUEUE_FLAG_FAIL_IO, &q->queue_flags)) | |
25 | return 0; | |
26 | ||
27 | return should_fail(&fail_io_timeout, 1); | |
28 | } | |
29 | ||
30 | static int __init fail_io_timeout_debugfs(void) | |
31 | { | |
dd48c085 AM |
32 | struct dentry *dir = fault_create_debugfs_attr("fail_io_timeout", |
33 | NULL, &fail_io_timeout); | |
34 | ||
8616ebb1 | 35 | return PTR_ERR_OR_ZERO(dir); |
581d4e28 JA |
36 | } |
37 | ||
38 | late_initcall(fail_io_timeout_debugfs); | |
39 | ||
40 | ssize_t part_timeout_show(struct device *dev, struct device_attribute *attr, | |
41 | char *buf) | |
42 | { | |
43 | struct gendisk *disk = dev_to_disk(dev); | |
44 | int set = test_bit(QUEUE_FLAG_FAIL_IO, &disk->queue->queue_flags); | |
45 | ||
46 | return sprintf(buf, "%d\n", set != 0); | |
47 | } | |
48 | ||
49 | ssize_t part_timeout_store(struct device *dev, struct device_attribute *attr, | |
50 | const char *buf, size_t count) | |
51 | { | |
52 | struct gendisk *disk = dev_to_disk(dev); | |
53 | int val; | |
54 | ||
55 | if (count) { | |
56 | struct request_queue *q = disk->queue; | |
57 | char *p = (char *) buf; | |
58 | ||
59 | val = simple_strtoul(p, &p, 10); | |
60 | spin_lock_irq(q->queue_lock); | |
61 | if (val) | |
62 | queue_flag_set(QUEUE_FLAG_FAIL_IO, q); | |
63 | else | |
64 | queue_flag_clear(QUEUE_FLAG_FAIL_IO, q); | |
65 | spin_unlock_irq(q->queue_lock); | |
66 | } | |
67 | ||
68 | return count; | |
69 | } | |
70 | ||
71 | #endif /* CONFIG_FAIL_IO_TIMEOUT */ | |
72 | ||
242f9dcb JA |
73 | /* |
74 | * blk_delete_timer - Delete/cancel timer for a given function. | |
75 | * @req: request that we are canceling timer for | |
76 | * | |
77 | */ | |
78 | void blk_delete_timer(struct request *req) | |
79 | { | |
242f9dcb | 80 | list_del_init(&req->timeout_list); |
242f9dcb JA |
81 | } |
82 | ||
83 | static void blk_rq_timed_out(struct request *req) | |
84 | { | |
85 | struct request_queue *q = req->q; | |
80bd7181 | 86 | enum blk_eh_timer_return ret = BLK_EH_RESET_TIMER; |
242f9dcb | 87 | |
80bd7181 HR |
88 | if (q->rq_timed_out_fn) |
89 | ret = q->rq_timed_out_fn(req); | |
242f9dcb JA |
90 | switch (ret) { |
91 | case BLK_EH_HANDLED: | |
46f92d42 | 92 | __blk_complete_request(req); |
242f9dcb JA |
93 | break; |
94 | case BLK_EH_RESET_TIMER: | |
87ee7b11 | 95 | blk_add_timer(req); |
4912aa6c | 96 | blk_clear_rq_complete(req); |
242f9dcb JA |
97 | break; |
98 | case BLK_EH_NOT_HANDLED: | |
99 | /* | |
100 | * LLD handles this for now but in the future | |
101 | * we can send a request msg to abort the command | |
102 | * and we can move more of the generic scsi eh code to | |
103 | * the blk layer. | |
104 | */ | |
105 | break; | |
106 | default: | |
107 | printk(KERN_ERR "block: bad eh return: %d\n", ret); | |
108 | break; | |
109 | } | |
110 | } | |
111 | ||
46f92d42 | 112 | static void blk_rq_check_expired(struct request *rq, unsigned long *next_timeout, |
320ae51f JA |
113 | unsigned int *next_set) |
114 | { | |
0a72e7f4 JA |
115 | const unsigned long deadline = blk_rq_deadline(rq); |
116 | ||
117 | if (time_after_eq(jiffies, deadline)) { | |
320ae51f JA |
118 | list_del_init(&rq->timeout_list); |
119 | ||
120 | /* | |
121 | * Check if we raced with end io completion | |
122 | */ | |
123 | if (!blk_mark_rq_complete(rq)) | |
124 | blk_rq_timed_out(rq); | |
0a72e7f4 JA |
125 | } else if (!*next_set || time_after(*next_timeout, deadline)) { |
126 | *next_timeout = deadline; | |
320ae51f JA |
127 | *next_set = 1; |
128 | } | |
129 | } | |
130 | ||
287922eb | 131 | void blk_timeout_work(struct work_struct *work) |
242f9dcb | 132 | { |
287922eb CH |
133 | struct request_queue *q = |
134 | container_of(work, struct request_queue, timeout_work); | |
565e411d | 135 | unsigned long flags, next = 0; |
242f9dcb | 136 | struct request *rq, *tmp; |
a534dbe9 | 137 | int next_set = 0; |
242f9dcb JA |
138 | |
139 | spin_lock_irqsave(q->queue_lock, flags); | |
140 | ||
320ae51f JA |
141 | list_for_each_entry_safe(rq, tmp, &q->timeout_list, timeout_list) |
142 | blk_rq_check_expired(rq, &next, &next_set); | |
242f9dcb | 143 | |
a534dbe9 | 144 | if (next_set) |
7838c15b | 145 | mod_timer(&q->timeout, round_jiffies_up(next)); |
242f9dcb JA |
146 | |
147 | spin_unlock_irqrestore(q->queue_lock, flags); | |
148 | } | |
149 | ||
150 | /** | |
151 | * blk_abort_request -- Request request recovery for the specified command | |
152 | * @req: pointer to the request of interest | |
153 | * | |
154 | * This function requests that the block layer start recovery for the | |
155 | * request by deleting the timer and calling the q's timeout function. | |
156 | * LLDDs who implement their own error recovery MAY ignore the timeout | |
157 | * event if they generated blk_abort_req. Must hold queue lock. | |
158 | */ | |
159 | void blk_abort_request(struct request *req) | |
160 | { | |
55ce0da1 | 161 | if (req->q->mq_ops) { |
358f70da TH |
162 | /* |
163 | * All we need to ensure is that timeout scan takes place | |
164 | * immediately and that scan sees the new timeout value. | |
165 | * No need for fancy synchronizations. | |
166 | */ | |
0a72e7f4 | 167 | blk_rq_set_deadline(req, jiffies); |
358f70da | 168 | mod_timer(&req->q->timeout, 0); |
55ce0da1 | 169 | } else { |
358f70da TH |
170 | if (blk_mark_rq_complete(req)) |
171 | return; | |
55ce0da1 | 172 | blk_delete_timer(req); |
90415837 | 173 | blk_rq_timed_out(req); |
55ce0da1 | 174 | } |
242f9dcb JA |
175 | } |
176 | EXPORT_SYMBOL_GPL(blk_abort_request); | |
177 | ||
0d2602ca JA |
178 | unsigned long blk_rq_timeout(unsigned long timeout) |
179 | { | |
180 | unsigned long maxt; | |
181 | ||
182 | maxt = round_jiffies_up(jiffies + BLK_MAX_TIMEOUT); | |
183 | if (time_after(timeout, maxt)) | |
184 | timeout = maxt; | |
185 | ||
186 | return timeout; | |
187 | } | |
188 | ||
c4a634f4 CH |
189 | /** |
190 | * blk_add_timer - Start timeout timer for a single request | |
191 | * @req: request that is about to start running. | |
192 | * | |
193 | * Notes: | |
194 | * Each request has its own timer, and as it is added to the queue, we | |
195 | * set up the timer. When the request completes, we cancel the timer. | |
196 | */ | |
197 | void blk_add_timer(struct request *req) | |
242f9dcb JA |
198 | { |
199 | struct request_queue *q = req->q; | |
200 | unsigned long expiry; | |
201 | ||
2fff8a92 BVA |
202 | if (!q->mq_ops) |
203 | lockdep_assert_held(q->queue_lock); | |
204 | ||
5e940aaa ML |
205 | /* blk-mq has its own handler, so we don't need ->rq_timed_out_fn */ |
206 | if (!q->mq_ops && !q->rq_timed_out_fn) | |
242f9dcb JA |
207 | return; |
208 | ||
209 | BUG_ON(!list_empty(&req->timeout_list)); | |
242f9dcb | 210 | |
2eef33e4 TH |
211 | /* |
212 | * Some LLDs, like scsi, peek at the timeout to prevent a | |
213 | * command from being retried forever. | |
214 | */ | |
215 | if (!req->timeout) | |
242f9dcb | 216 | req->timeout = q->rq_timeout; |
2eef33e4 | 217 | |
0a72e7f4 | 218 | blk_rq_set_deadline(req, jiffies + req->timeout); |
634f9e46 | 219 | req->rq_flags &= ~RQF_MQ_TIMEOUT_EXPIRED; |
3b627a3f JA |
220 | |
221 | /* | |
222 | * Only the non-mq case needs to add the request to a protected list. | |
223 | * For the mq case we simply scan the tag map. | |
224 | */ | |
c4a634f4 CH |
225 | if (!q->mq_ops) |
226 | list_add_tail(&req->timeout_list, &req->q->timeout_list); | |
242f9dcb JA |
227 | |
228 | /* | |
229 | * If the timer isn't already pending or this timeout is earlier | |
7838c15b | 230 | * than an existing one, modify the timer. Round up to next nearest |
242f9dcb JA |
231 | * second. |
232 | */ | |
0a72e7f4 | 233 | expiry = blk_rq_timeout(round_jiffies_up(blk_rq_deadline(req))); |
242f9dcb JA |
234 | |
235 | if (!timer_pending(&q->timeout) || | |
f793aa53 JA |
236 | time_before(expiry, q->timeout.expires)) { |
237 | unsigned long diff = q->timeout.expires - expiry; | |
238 | ||
239 | /* | |
240 | * Due to added timer slack to group timers, the timer | |
241 | * will often be a little in front of what we asked for. | |
242 | * So apply some tolerance here too, otherwise we keep | |
243 | * modifying the timer because expires for value X | |
244 | * will be X + something. | |
245 | */ | |
c7bca418 | 246 | if (!timer_pending(&q->timeout) || (diff >= HZ / 2)) |
f793aa53 JA |
247 | mod_timer(&q->timeout, expiry); |
248 | } | |
320ae51f JA |
249 | |
250 | } |