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" | |
10 | ||
581d4e28 JA |
11 | #ifdef CONFIG_FAIL_IO_TIMEOUT |
12 | ||
13 | static DECLARE_FAULT_ATTR(fail_io_timeout); | |
14 | ||
15 | static int __init setup_fail_io_timeout(char *str) | |
16 | { | |
17 | return setup_fault_attr(&fail_io_timeout, str); | |
18 | } | |
19 | __setup("fail_io_timeout=", setup_fail_io_timeout); | |
20 | ||
21 | int blk_should_fake_timeout(struct request_queue *q) | |
22 | { | |
23 | if (!test_bit(QUEUE_FLAG_FAIL_IO, &q->queue_flags)) | |
24 | return 0; | |
25 | ||
26 | return should_fail(&fail_io_timeout, 1); | |
27 | } | |
28 | ||
29 | static int __init fail_io_timeout_debugfs(void) | |
30 | { | |
dd48c085 AM |
31 | struct dentry *dir = fault_create_debugfs_attr("fail_io_timeout", |
32 | NULL, &fail_io_timeout); | |
33 | ||
8616ebb1 | 34 | return PTR_ERR_OR_ZERO(dir); |
581d4e28 JA |
35 | } |
36 | ||
37 | late_initcall(fail_io_timeout_debugfs); | |
38 | ||
39 | ssize_t part_timeout_show(struct device *dev, struct device_attribute *attr, | |
40 | char *buf) | |
41 | { | |
42 | struct gendisk *disk = dev_to_disk(dev); | |
43 | int set = test_bit(QUEUE_FLAG_FAIL_IO, &disk->queue->queue_flags); | |
44 | ||
45 | return sprintf(buf, "%d\n", set != 0); | |
46 | } | |
47 | ||
48 | ssize_t part_timeout_store(struct device *dev, struct device_attribute *attr, | |
49 | const char *buf, size_t count) | |
50 | { | |
51 | struct gendisk *disk = dev_to_disk(dev); | |
52 | int val; | |
53 | ||
54 | if (count) { | |
55 | struct request_queue *q = disk->queue; | |
56 | char *p = (char *) buf; | |
57 | ||
58 | val = simple_strtoul(p, &p, 10); | |
59 | spin_lock_irq(q->queue_lock); | |
60 | if (val) | |
61 | queue_flag_set(QUEUE_FLAG_FAIL_IO, q); | |
62 | else | |
63 | queue_flag_clear(QUEUE_FLAG_FAIL_IO, q); | |
64 | spin_unlock_irq(q->queue_lock); | |
65 | } | |
66 | ||
67 | return count; | |
68 | } | |
69 | ||
70 | #endif /* CONFIG_FAIL_IO_TIMEOUT */ | |
71 | ||
242f9dcb JA |
72 | /* |
73 | * blk_delete_timer - Delete/cancel timer for a given function. | |
74 | * @req: request that we are canceling timer for | |
75 | * | |
76 | */ | |
77 | void blk_delete_timer(struct request *req) | |
78 | { | |
242f9dcb | 79 | list_del_init(&req->timeout_list); |
242f9dcb JA |
80 | } |
81 | ||
82 | static void blk_rq_timed_out(struct request *req) | |
83 | { | |
84 | struct request_queue *q = req->q; | |
80bd7181 | 85 | enum blk_eh_timer_return ret = BLK_EH_RESET_TIMER; |
242f9dcb | 86 | |
80bd7181 HR |
87 | if (q->rq_timed_out_fn) |
88 | ret = q->rq_timed_out_fn(req); | |
242f9dcb JA |
89 | switch (ret) { |
90 | case BLK_EH_HANDLED: | |
320ae51f | 91 | /* Can we use req->errors here? */ |
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 | { | |
115 | if (time_after_eq(jiffies, rq->deadline)) { | |
116 | list_del_init(&rq->timeout_list); | |
117 | ||
118 | /* | |
119 | * Check if we raced with end io completion | |
120 | */ | |
121 | if (!blk_mark_rq_complete(rq)) | |
122 | blk_rq_timed_out(rq); | |
123 | } else if (!*next_set || time_after(*next_timeout, rq->deadline)) { | |
124 | *next_timeout = rq->deadline; | |
125 | *next_set = 1; | |
126 | } | |
127 | } | |
128 | ||
242f9dcb JA |
129 | void blk_rq_timed_out_timer(unsigned long data) |
130 | { | |
131 | struct request_queue *q = (struct request_queue *) data; | |
565e411d | 132 | unsigned long flags, next = 0; |
242f9dcb | 133 | struct request *rq, *tmp; |
a534dbe9 | 134 | int next_set = 0; |
242f9dcb JA |
135 | |
136 | spin_lock_irqsave(q->queue_lock, flags); | |
137 | ||
320ae51f JA |
138 | list_for_each_entry_safe(rq, tmp, &q->timeout_list, timeout_list) |
139 | blk_rq_check_expired(rq, &next, &next_set); | |
242f9dcb | 140 | |
a534dbe9 | 141 | if (next_set) |
7838c15b | 142 | mod_timer(&q->timeout, round_jiffies_up(next)); |
242f9dcb JA |
143 | |
144 | spin_unlock_irqrestore(q->queue_lock, flags); | |
145 | } | |
146 | ||
147 | /** | |
148 | * blk_abort_request -- Request request recovery for the specified command | |
149 | * @req: pointer to the request of interest | |
150 | * | |
151 | * This function requests that the block layer start recovery for the | |
152 | * request by deleting the timer and calling the q's timeout function. | |
153 | * LLDDs who implement their own error recovery MAY ignore the timeout | |
154 | * event if they generated blk_abort_req. Must hold queue lock. | |
155 | */ | |
156 | void blk_abort_request(struct request *req) | |
157 | { | |
7ba1fbaa JA |
158 | if (blk_mark_rq_complete(req)) |
159 | return; | |
242f9dcb JA |
160 | blk_delete_timer(req); |
161 | blk_rq_timed_out(req); | |
162 | } | |
163 | EXPORT_SYMBOL_GPL(blk_abort_request); | |
164 | ||
0d2602ca JA |
165 | unsigned long blk_rq_timeout(unsigned long timeout) |
166 | { | |
167 | unsigned long maxt; | |
168 | ||
169 | maxt = round_jiffies_up(jiffies + BLK_MAX_TIMEOUT); | |
170 | if (time_after(timeout, maxt)) | |
171 | timeout = maxt; | |
172 | ||
173 | return timeout; | |
174 | } | |
175 | ||
c4a634f4 CH |
176 | /** |
177 | * blk_add_timer - Start timeout timer for a single request | |
178 | * @req: request that is about to start running. | |
179 | * | |
180 | * Notes: | |
181 | * Each request has its own timer, and as it is added to the queue, we | |
182 | * set up the timer. When the request completes, we cancel the timer. | |
183 | */ | |
184 | void blk_add_timer(struct request *req) | |
242f9dcb JA |
185 | { |
186 | struct request_queue *q = req->q; | |
187 | unsigned long expiry; | |
188 | ||
5e940aaa ML |
189 | /* blk-mq has its own handler, so we don't need ->rq_timed_out_fn */ |
190 | if (!q->mq_ops && !q->rq_timed_out_fn) | |
242f9dcb JA |
191 | return; |
192 | ||
193 | BUG_ON(!list_empty(&req->timeout_list)); | |
242f9dcb | 194 | |
2eef33e4 TH |
195 | /* |
196 | * Some LLDs, like scsi, peek at the timeout to prevent a | |
197 | * command from being retried forever. | |
198 | */ | |
199 | if (!req->timeout) | |
242f9dcb | 200 | req->timeout = q->rq_timeout; |
2eef33e4 TH |
201 | |
202 | req->deadline = jiffies + req->timeout; | |
c4a634f4 CH |
203 | if (!q->mq_ops) |
204 | list_add_tail(&req->timeout_list, &req->q->timeout_list); | |
242f9dcb JA |
205 | |
206 | /* | |
207 | * If the timer isn't already pending or this timeout is earlier | |
7838c15b | 208 | * than an existing one, modify the timer. Round up to next nearest |
242f9dcb JA |
209 | * second. |
210 | */ | |
0d2602ca | 211 | expiry = blk_rq_timeout(round_jiffies_up(req->deadline)); |
242f9dcb JA |
212 | |
213 | if (!timer_pending(&q->timeout) || | |
f793aa53 JA |
214 | time_before(expiry, q->timeout.expires)) { |
215 | unsigned long diff = q->timeout.expires - expiry; | |
216 | ||
217 | /* | |
218 | * Due to added timer slack to group timers, the timer | |
219 | * will often be a little in front of what we asked for. | |
220 | * So apply some tolerance here too, otherwise we keep | |
221 | * modifying the timer because expires for value X | |
222 | * will be X + something. | |
223 | */ | |
c7bca418 | 224 | if (!timer_pending(&q->timeout) || (diff >= HZ / 2)) |
f793aa53 JA |
225 | mod_timer(&q->timeout, expiry); |
226 | } | |
320ae51f JA |
227 | |
228 | } |