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 | { | |
31 | return init_fault_attr_dentries(&fail_io_timeout, "fail_io_timeout"); | |
32 | } | |
33 | ||
34 | late_initcall(fail_io_timeout_debugfs); | |
35 | ||
36 | ssize_t part_timeout_show(struct device *dev, struct device_attribute *attr, | |
37 | char *buf) | |
38 | { | |
39 | struct gendisk *disk = dev_to_disk(dev); | |
40 | int set = test_bit(QUEUE_FLAG_FAIL_IO, &disk->queue->queue_flags); | |
41 | ||
42 | return sprintf(buf, "%d\n", set != 0); | |
43 | } | |
44 | ||
45 | ssize_t part_timeout_store(struct device *dev, struct device_attribute *attr, | |
46 | const char *buf, size_t count) | |
47 | { | |
48 | struct gendisk *disk = dev_to_disk(dev); | |
49 | int val; | |
50 | ||
51 | if (count) { | |
52 | struct request_queue *q = disk->queue; | |
53 | char *p = (char *) buf; | |
54 | ||
55 | val = simple_strtoul(p, &p, 10); | |
56 | spin_lock_irq(q->queue_lock); | |
57 | if (val) | |
58 | queue_flag_set(QUEUE_FLAG_FAIL_IO, q); | |
59 | else | |
60 | queue_flag_clear(QUEUE_FLAG_FAIL_IO, q); | |
61 | spin_unlock_irq(q->queue_lock); | |
62 | } | |
63 | ||
64 | return count; | |
65 | } | |
66 | ||
67 | #endif /* CONFIG_FAIL_IO_TIMEOUT */ | |
68 | ||
242f9dcb JA |
69 | /* |
70 | * blk_delete_timer - Delete/cancel timer for a given function. | |
71 | * @req: request that we are canceling timer for | |
72 | * | |
73 | */ | |
74 | void blk_delete_timer(struct request *req) | |
75 | { | |
242f9dcb | 76 | list_del_init(&req->timeout_list); |
242f9dcb JA |
77 | } |
78 | ||
79 | static void blk_rq_timed_out(struct request *req) | |
80 | { | |
81 | struct request_queue *q = req->q; | |
82 | enum blk_eh_timer_return ret; | |
83 | ||
84 | ret = q->rq_timed_out_fn(req); | |
85 | switch (ret) { | |
86 | case BLK_EH_HANDLED: | |
87 | __blk_complete_request(req); | |
88 | break; | |
89 | case BLK_EH_RESET_TIMER: | |
90 | blk_clear_rq_complete(req); | |
91 | blk_add_timer(req); | |
92 | break; | |
93 | case BLK_EH_NOT_HANDLED: | |
94 | /* | |
95 | * LLD handles this for now but in the future | |
96 | * we can send a request msg to abort the command | |
97 | * and we can move more of the generic scsi eh code to | |
98 | * the blk layer. | |
99 | */ | |
100 | break; | |
101 | default: | |
102 | printk(KERN_ERR "block: bad eh return: %d\n", ret); | |
103 | break; | |
104 | } | |
105 | } | |
106 | ||
107 | void blk_rq_timed_out_timer(unsigned long data) | |
108 | { | |
109 | struct request_queue *q = (struct request_queue *) data; | |
565e411d | 110 | unsigned long flags, next = 0; |
242f9dcb JA |
111 | struct request *rq, *tmp; |
112 | ||
113 | spin_lock_irqsave(q->queue_lock, flags); | |
114 | ||
115 | list_for_each_entry_safe(rq, tmp, &q->timeout_list, timeout_list) { | |
116 | if (time_after_eq(jiffies, rq->deadline)) { | |
117 | list_del_init(&rq->timeout_list); | |
118 | ||
119 | /* | |
120 | * Check if we raced with end io completion | |
121 | */ | |
122 | if (blk_mark_rq_complete(rq)) | |
123 | continue; | |
124 | blk_rq_timed_out(rq); | |
565e411d | 125 | } else { |
126 | if (!next || time_after(next, rq->deadline)) | |
127 | next = rq->deadline; | |
242f9dcb | 128 | } |
242f9dcb JA |
129 | } |
130 | ||
65d3618c JA |
131 | /* |
132 | * next can never be 0 here with the list non-empty, since we always | |
133 | * bump ->deadline to 1 so we can detect if the timer was ever added | |
134 | * or not. See comment in blk_add_timer() | |
135 | */ | |
136 | if (next) | |
7838c15b | 137 | mod_timer(&q->timeout, round_jiffies_up(next)); |
242f9dcb JA |
138 | |
139 | spin_unlock_irqrestore(q->queue_lock, flags); | |
140 | } | |
141 | ||
142 | /** | |
143 | * blk_abort_request -- Request request recovery for the specified command | |
144 | * @req: pointer to the request of interest | |
145 | * | |
146 | * This function requests that the block layer start recovery for the | |
147 | * request by deleting the timer and calling the q's timeout function. | |
148 | * LLDDs who implement their own error recovery MAY ignore the timeout | |
149 | * event if they generated blk_abort_req. Must hold queue lock. | |
150 | */ | |
151 | void blk_abort_request(struct request *req) | |
152 | { | |
7ba1fbaa JA |
153 | if (blk_mark_rq_complete(req)) |
154 | return; | |
242f9dcb JA |
155 | blk_delete_timer(req); |
156 | blk_rq_timed_out(req); | |
157 | } | |
158 | EXPORT_SYMBOL_GPL(blk_abort_request); | |
159 | ||
160 | /** | |
161 | * blk_add_timer - Start timeout timer for a single request | |
162 | * @req: request that is about to start running. | |
163 | * | |
164 | * Notes: | |
165 | * Each request has its own timer, and as it is added to the queue, we | |
166 | * set up the timer. When the request completes, we cancel the timer. | |
167 | */ | |
168 | void blk_add_timer(struct request *req) | |
169 | { | |
170 | struct request_queue *q = req->q; | |
171 | unsigned long expiry; | |
172 | ||
173 | if (!q->rq_timed_out_fn) | |
174 | return; | |
175 | ||
176 | BUG_ON(!list_empty(&req->timeout_list)); | |
177 | BUG_ON(test_bit(REQ_ATOM_COMPLETE, &req->atomic_flags)); | |
178 | ||
179 | if (req->timeout) | |
180 | req->deadline = jiffies + req->timeout; | |
181 | else { | |
182 | req->deadline = jiffies + q->rq_timeout; | |
183 | /* | |
184 | * Some LLDs, like scsi, peek at the timeout to prevent | |
185 | * a command from being retried forever. | |
186 | */ | |
187 | req->timeout = q->rq_timeout; | |
188 | } | |
189 | list_add_tail(&req->timeout_list, &q->timeout_list); | |
190 | ||
191 | /* | |
192 | * If the timer isn't already pending or this timeout is earlier | |
7838c15b | 193 | * than an existing one, modify the timer. Round up to next nearest |
242f9dcb JA |
194 | * second. |
195 | */ | |
7838c15b | 196 | expiry = round_jiffies_up(req->deadline); |
242f9dcb JA |
197 | |
198 | if (!timer_pending(&q->timeout) || | |
199 | time_before(expiry, q->timeout.expires)) | |
200 | mod_timer(&q->timeout, expiry); | |
201 | } | |
11914a53 MA |
202 | |
203 | /** | |
204 | * blk_abort_queue -- Abort all request on given queue | |
205 | * @queue: pointer to queue | |
206 | * | |
207 | */ | |
208 | void blk_abort_queue(struct request_queue *q) | |
209 | { | |
210 | unsigned long flags; | |
211 | struct request *rq, *tmp; | |
be987fdb | 212 | LIST_HEAD(list); |
11914a53 | 213 | |
b7591134 JA |
214 | /* |
215 | * Not a request based block device, nothing to abort | |
216 | */ | |
217 | if (!q->request_fn) | |
218 | return; | |
219 | ||
11914a53 MA |
220 | spin_lock_irqsave(q->queue_lock, flags); |
221 | ||
222 | elv_abort_queue(q); | |
223 | ||
be987fdb HR |
224 | /* |
225 | * Splice entries to local list, to avoid deadlocking if entries | |
226 | * get readded to the timeout list by error handling | |
227 | */ | |
228 | list_splice_init(&q->timeout_list, &list); | |
229 | ||
230 | list_for_each_entry_safe(rq, tmp, &list, timeout_list) | |
11914a53 MA |
231 | blk_abort_request(rq); |
232 | ||
17d5c8ca HR |
233 | /* |
234 | * Occasionally, blk_abort_request() will return without | |
235 | * deleting the element from the list. Make sure we add those back | |
236 | * instead of leaving them on the local stack list. | |
237 | */ | |
238 | list_splice(&list, &q->timeout_list); | |
239 | ||
11914a53 MA |
240 | spin_unlock_irqrestore(q->queue_lock, flags); |
241 | ||
242 | } | |
243 | EXPORT_SYMBOL_GPL(blk_abort_queue); |