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Jens Axboe242f9dc2008-09-14 05:55:09 -07001/*
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>
Jens Axboe581d4e22008-09-14 05:56:33 -07007#include <linux/fault-inject.h>
Jens Axboe242f9dc2008-09-14 05:55:09 -07008
9#include "blk.h"
10
Jens Axboe581d4e22008-09-14 05:56:33 -070011#ifdef CONFIG_FAIL_IO_TIMEOUT
12
13static DECLARE_FAULT_ATTR(fail_io_timeout);
14
15static 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
21int 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
29static int __init fail_io_timeout_debugfs(void)
30{
31 return init_fault_attr_dentries(&fail_io_timeout, "fail_io_timeout");
32}
33
34late_initcall(fail_io_timeout_debugfs);
35
36ssize_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
45ssize_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
Jens Axboe242f9dc2008-09-14 05:55:09 -070069/*
70 * blk_delete_timer - Delete/cancel timer for a given function.
71 * @req: request that we are canceling timer for
72 *
73 */
74void blk_delete_timer(struct request *req)
75{
Jens Axboe242f9dc2008-09-14 05:55:09 -070076 list_del_init(&req->timeout_list);
Jens Axboe242f9dc2008-09-14 05:55:09 -070077}
78
79static 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
107void blk_rq_timed_out_timer(unsigned long data)
108{
109 struct request_queue *q = (struct request_queue *) data;
malahal@us.ibm.com565e4112008-10-30 08:51:58 +0100110 unsigned long flags, next = 0;
Jens Axboe242f9dc2008-09-14 05:55:09 -0700111 struct request *rq, *tmp;
Richard Kennedya534dbe2010-04-14 20:54:03 +0200112 int next_set = 0;
Jens Axboe242f9dc2008-09-14 05:55:09 -0700113
114 spin_lock_irqsave(q->queue_lock, flags);
115
116 list_for_each_entry_safe(rq, tmp, &q->timeout_list, timeout_list) {
117 if (time_after_eq(jiffies, rq->deadline)) {
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 continue;
125 blk_rq_timed_out(rq);
Richard Kennedya534dbe2010-04-14 20:54:03 +0200126 } else if (!next_set || time_after(next, rq->deadline)) {
Tejun Heo2eef33e2009-04-23 11:05:18 +0900127 next = rq->deadline;
Richard Kennedya534dbe2010-04-14 20:54:03 +0200128 next_set = 1;
129 }
Jens Axboe242f9dc2008-09-14 05:55:09 -0700130 }
131
Richard Kennedya534dbe2010-04-14 20:54:03 +0200132 if (next_set)
Alan Stern7838c152008-11-06 08:42:49 +0100133 mod_timer(&q->timeout, round_jiffies_up(next));
Jens Axboe242f9dc2008-09-14 05:55:09 -0700134
135 spin_unlock_irqrestore(q->queue_lock, flags);
136}
137
138/**
139 * blk_abort_request -- Request request recovery for the specified command
140 * @req: pointer to the request of interest
141 *
142 * This function requests that the block layer start recovery for the
143 * request by deleting the timer and calling the q's timeout function.
144 * LLDDs who implement their own error recovery MAY ignore the timeout
145 * event if they generated blk_abort_req. Must hold queue lock.
146 */
147void blk_abort_request(struct request *req)
148{
Jens Axboe7ba1fba2008-09-16 09:54:11 -0700149 if (blk_mark_rq_complete(req))
150 return;
Jens Axboe242f9dc2008-09-14 05:55:09 -0700151 blk_delete_timer(req);
152 blk_rq_timed_out(req);
153}
154EXPORT_SYMBOL_GPL(blk_abort_request);
155
156/**
157 * blk_add_timer - Start timeout timer for a single request
158 * @req: request that is about to start running.
159 *
160 * Notes:
161 * Each request has its own timer, and as it is added to the queue, we
162 * set up the timer. When the request completes, we cancel the timer.
163 */
164void blk_add_timer(struct request *req)
165{
166 struct request_queue *q = req->q;
167 unsigned long expiry;
168
169 if (!q->rq_timed_out_fn)
170 return;
171
172 BUG_ON(!list_empty(&req->timeout_list));
173 BUG_ON(test_bit(REQ_ATOM_COMPLETE, &req->atomic_flags));
174
Tejun Heo2eef33e2009-04-23 11:05:18 +0900175 /*
176 * Some LLDs, like scsi, peek at the timeout to prevent a
177 * command from being retried forever.
178 */
179 if (!req->timeout)
Jens Axboe242f9dc2008-09-14 05:55:09 -0700180 req->timeout = q->rq_timeout;
Tejun Heo2eef33e2009-04-23 11:05:18 +0900181
182 req->deadline = jiffies + req->timeout;
Jens Axboe242f9dc2008-09-14 05:55:09 -0700183 list_add_tail(&req->timeout_list, &q->timeout_list);
184
185 /*
186 * If the timer isn't already pending or this timeout is earlier
Alan Stern7838c152008-11-06 08:42:49 +0100187 * than an existing one, modify the timer. Round up to next nearest
Jens Axboe242f9dc2008-09-14 05:55:09 -0700188 * second.
189 */
Alan Stern7838c152008-11-06 08:42:49 +0100190 expiry = round_jiffies_up(req->deadline);
Jens Axboe242f9dc2008-09-14 05:55:09 -0700191
192 if (!timer_pending(&q->timeout) ||
193 time_before(expiry, q->timeout.expires))
194 mod_timer(&q->timeout, expiry);
195}
Mike Anderson11914a52008-09-13 20:31:27 +0200196
197/**
198 * blk_abort_queue -- Abort all request on given queue
199 * @queue: pointer to queue
200 *
201 */
202void blk_abort_queue(struct request_queue *q)
203{
204 unsigned long flags;
205 struct request *rq, *tmp;
Hannes Reineckebe987fd2009-02-18 10:30:15 +0100206 LIST_HEAD(list);
Mike Anderson11914a52008-09-13 20:31:27 +0200207
Jens Axboeb7591132009-04-17 08:36:50 +0200208 /*
209 * Not a request based block device, nothing to abort
210 */
211 if (!q->request_fn)
212 return;
213
Mike Anderson11914a52008-09-13 20:31:27 +0200214 spin_lock_irqsave(q->queue_lock, flags);
215
216 elv_abort_queue(q);
217
Hannes Reineckebe987fd2009-02-18 10:30:15 +0100218 /*
219 * Splice entries to local list, to avoid deadlocking if entries
220 * get readded to the timeout list by error handling
221 */
222 list_splice_init(&q->timeout_list, &list);
223
224 list_for_each_entry_safe(rq, tmp, &list, timeout_list)
Mike Anderson11914a52008-09-13 20:31:27 +0200225 blk_abort_request(rq);
226
Hannes Reinecke17d5c8c2009-04-23 10:32:59 +0200227 /*
228 * Occasionally, blk_abort_request() will return without
229 * deleting the element from the list. Make sure we add those back
230 * instead of leaving them on the local stack list.
231 */
232 list_splice(&list, &q->timeout_list);
233
Mike Anderson11914a52008-09-13 20:31:27 +0200234 spin_unlock_irqrestore(q->queue_lock, flags);
235
236}
237EXPORT_SYMBOL_GPL(blk_abort_queue);