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 | { | |
76 | struct request_queue *q = req->q; | |
77 | ||
78 | /* | |
79 | * Nothing to detach | |
80 | */ | |
81 | if (!q->rq_timed_out_fn || !req->deadline) | |
82 | return; | |
83 | ||
84 | list_del_init(&req->timeout_list); | |
85 | ||
86 | if (list_empty(&q->timeout_list)) | |
87 | del_timer(&q->timeout); | |
88 | } | |
89 | ||
90 | static void blk_rq_timed_out(struct request *req) | |
91 | { | |
92 | struct request_queue *q = req->q; | |
93 | enum blk_eh_timer_return ret; | |
94 | ||
95 | ret = q->rq_timed_out_fn(req); | |
96 | switch (ret) { | |
97 | case BLK_EH_HANDLED: | |
98 | __blk_complete_request(req); | |
99 | break; | |
100 | case BLK_EH_RESET_TIMER: | |
101 | blk_clear_rq_complete(req); | |
102 | blk_add_timer(req); | |
103 | break; | |
104 | case BLK_EH_NOT_HANDLED: | |
105 | /* | |
106 | * LLD handles this for now but in the future | |
107 | * we can send a request msg to abort the command | |
108 | * and we can move more of the generic scsi eh code to | |
109 | * the blk layer. | |
110 | */ | |
111 | break; | |
112 | default: | |
113 | printk(KERN_ERR "block: bad eh return: %d\n", ret); | |
114 | break; | |
115 | } | |
116 | } | |
117 | ||
118 | void blk_rq_timed_out_timer(unsigned long data) | |
119 | { | |
120 | struct request_queue *q = (struct request_queue *) data; | |
121 | unsigned long flags, uninitialized_var(next), next_set = 0; | |
122 | struct request *rq, *tmp; | |
123 | ||
124 | spin_lock_irqsave(q->queue_lock, flags); | |
125 | ||
126 | list_for_each_entry_safe(rq, tmp, &q->timeout_list, timeout_list) { | |
127 | if (time_after_eq(jiffies, rq->deadline)) { | |
128 | list_del_init(&rq->timeout_list); | |
129 | ||
130 | /* | |
131 | * Check if we raced with end io completion | |
132 | */ | |
133 | if (blk_mark_rq_complete(rq)) | |
134 | continue; | |
135 | blk_rq_timed_out(rq); | |
136 | } | |
137 | if (!next_set) { | |
138 | next = rq->deadline; | |
139 | next_set = 1; | |
140 | } else if (time_after(next, rq->deadline)) | |
141 | next = rq->deadline; | |
142 | } | |
143 | ||
144 | if (next_set && !list_empty(&q->timeout_list)) | |
145 | mod_timer(&q->timeout, round_jiffies(next)); | |
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 | { | |
7ba1fbaa JA |
161 | if (blk_mark_rq_complete(req)) |
162 | return; | |
242f9dcb JA |
163 | blk_delete_timer(req); |
164 | blk_rq_timed_out(req); | |
165 | } | |
166 | EXPORT_SYMBOL_GPL(blk_abort_request); | |
167 | ||
168 | /** | |
169 | * blk_add_timer - Start timeout timer for a single request | |
170 | * @req: request that is about to start running. | |
171 | * | |
172 | * Notes: | |
173 | * Each request has its own timer, and as it is added to the queue, we | |
174 | * set up the timer. When the request completes, we cancel the timer. | |
175 | */ | |
176 | void blk_add_timer(struct request *req) | |
177 | { | |
178 | struct request_queue *q = req->q; | |
179 | unsigned long expiry; | |
180 | ||
181 | if (!q->rq_timed_out_fn) | |
182 | return; | |
183 | ||
184 | BUG_ON(!list_empty(&req->timeout_list)); | |
185 | BUG_ON(test_bit(REQ_ATOM_COMPLETE, &req->atomic_flags)); | |
186 | ||
187 | if (req->timeout) | |
188 | req->deadline = jiffies + req->timeout; | |
189 | else { | |
190 | req->deadline = jiffies + q->rq_timeout; | |
191 | /* | |
192 | * Some LLDs, like scsi, peek at the timeout to prevent | |
193 | * a command from being retried forever. | |
194 | */ | |
195 | req->timeout = q->rq_timeout; | |
196 | } | |
197 | list_add_tail(&req->timeout_list, &q->timeout_list); | |
198 | ||
199 | /* | |
200 | * If the timer isn't already pending or this timeout is earlier | |
201 | * than an existing one, modify the timer. Round to next nearest | |
202 | * second. | |
203 | */ | |
204 | expiry = round_jiffies(req->deadline); | |
205 | ||
206 | /* | |
207 | * We use ->deadline == 0 to detect whether a timer was added or | |
208 | * not, so just increase to next jiffy for that specific case | |
209 | */ | |
210 | if (unlikely(!req->deadline)) | |
211 | req->deadline = 1; | |
212 | ||
213 | if (!timer_pending(&q->timeout) || | |
214 | time_before(expiry, q->timeout.expires)) | |
215 | mod_timer(&q->timeout, expiry); | |
216 | } | |
11914a53 MA |
217 | |
218 | /** | |
219 | * blk_abort_queue -- Abort all request on given queue | |
220 | * @queue: pointer to queue | |
221 | * | |
222 | */ | |
223 | void blk_abort_queue(struct request_queue *q) | |
224 | { | |
225 | unsigned long flags; | |
226 | struct request *rq, *tmp; | |
227 | ||
228 | spin_lock_irqsave(q->queue_lock, flags); | |
229 | ||
230 | elv_abort_queue(q); | |
231 | ||
232 | list_for_each_entry_safe(rq, tmp, &q->timeout_list, timeout_list) | |
233 | blk_abort_request(rq); | |
234 | ||
235 | spin_unlock_irqrestore(q->queue_lock, flags); | |
236 | ||
237 | } | |
238 | EXPORT_SYMBOL_GPL(blk_abort_queue); |