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 | ||
34 | return IS_ERR(dir) ? PTR_ERR(dir) : 0; | |
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; | |
85 | enum blk_eh_timer_return ret; | |
86 | ||
87 | ret = q->rq_timed_out_fn(req); | |
88 | switch (ret) { | |
89 | case BLK_EH_HANDLED: | |
90 | __blk_complete_request(req); | |
91 | break; | |
92 | case BLK_EH_RESET_TIMER: | |
93 | blk_clear_rq_complete(req); | |
94 | blk_add_timer(req); | |
95 | break; | |
96 | case BLK_EH_NOT_HANDLED: | |
97 | /* | |
98 | * LLD handles this for now but in the future | |
99 | * we can send a request msg to abort the command | |
100 | * and we can move more of the generic scsi eh code to | |
101 | * the blk layer. | |
102 | */ | |
103 | break; | |
104 | default: | |
105 | printk(KERN_ERR "block: bad eh return: %d\n", ret); | |
106 | break; | |
107 | } | |
108 | } | |
109 | ||
110 | void blk_rq_timed_out_timer(unsigned long data) | |
111 | { | |
112 | struct request_queue *q = (struct request_queue *) data; | |
565e411d | 113 | unsigned long flags, next = 0; |
242f9dcb | 114 | struct request *rq, *tmp; |
a534dbe9 | 115 | int next_set = 0; |
242f9dcb JA |
116 | |
117 | spin_lock_irqsave(q->queue_lock, flags); | |
118 | ||
119 | list_for_each_entry_safe(rq, tmp, &q->timeout_list, timeout_list) { | |
120 | if (time_after_eq(jiffies, rq->deadline)) { | |
121 | list_del_init(&rq->timeout_list); | |
122 | ||
123 | /* | |
124 | * Check if we raced with end io completion | |
125 | */ | |
126 | if (blk_mark_rq_complete(rq)) | |
127 | continue; | |
128 | blk_rq_timed_out(rq); | |
a534dbe9 | 129 | } else if (!next_set || time_after(next, rq->deadline)) { |
2eef33e4 | 130 | next = rq->deadline; |
a534dbe9 RK |
131 | next_set = 1; |
132 | } | |
242f9dcb JA |
133 | } |
134 | ||
a534dbe9 | 135 | if (next_set) |
7838c15b | 136 | mod_timer(&q->timeout, round_jiffies_up(next)); |
242f9dcb JA |
137 | |
138 | spin_unlock_irqrestore(q->queue_lock, flags); | |
139 | } | |
140 | ||
141 | /** | |
142 | * blk_abort_request -- Request request recovery for the specified command | |
143 | * @req: pointer to the request of interest | |
144 | * | |
145 | * This function requests that the block layer start recovery for the | |
146 | * request by deleting the timer and calling the q's timeout function. | |
147 | * LLDDs who implement their own error recovery MAY ignore the timeout | |
148 | * event if they generated blk_abort_req. Must hold queue lock. | |
149 | */ | |
150 | void blk_abort_request(struct request *req) | |
151 | { | |
7ba1fbaa JA |
152 | if (blk_mark_rq_complete(req)) |
153 | return; | |
242f9dcb JA |
154 | blk_delete_timer(req); |
155 | blk_rq_timed_out(req); | |
156 | } | |
157 | EXPORT_SYMBOL_GPL(blk_abort_request); | |
158 | ||
159 | /** | |
160 | * blk_add_timer - Start timeout timer for a single request | |
161 | * @req: request that is about to start running. | |
162 | * | |
163 | * Notes: | |
164 | * Each request has its own timer, and as it is added to the queue, we | |
165 | * set up the timer. When the request completes, we cancel the timer. | |
166 | */ | |
167 | void blk_add_timer(struct request *req) | |
168 | { | |
169 | struct request_queue *q = req->q; | |
170 | unsigned long expiry; | |
171 | ||
172 | if (!q->rq_timed_out_fn) | |
173 | return; | |
174 | ||
175 | BUG_ON(!list_empty(&req->timeout_list)); | |
176 | BUG_ON(test_bit(REQ_ATOM_COMPLETE, &req->atomic_flags)); | |
177 | ||
2eef33e4 TH |
178 | /* |
179 | * Some LLDs, like scsi, peek at the timeout to prevent a | |
180 | * command from being retried forever. | |
181 | */ | |
182 | if (!req->timeout) | |
242f9dcb | 183 | req->timeout = q->rq_timeout; |
2eef33e4 TH |
184 | |
185 | req->deadline = jiffies + req->timeout; | |
242f9dcb JA |
186 | list_add_tail(&req->timeout_list, &q->timeout_list); |
187 | ||
188 | /* | |
189 | * If the timer isn't already pending or this timeout is earlier | |
7838c15b | 190 | * than an existing one, modify the timer. Round up to next nearest |
242f9dcb JA |
191 | * second. |
192 | */ | |
7838c15b | 193 | expiry = round_jiffies_up(req->deadline); |
242f9dcb JA |
194 | |
195 | if (!timer_pending(&q->timeout) || | |
196 | time_before(expiry, q->timeout.expires)) | |
197 | mod_timer(&q->timeout, expiry); | |
198 | } | |
11914a53 | 199 |