blob: 65f103563969bf32391c7bb3d6f4e4859ed1459a [file] [log] [blame]
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{
Akinobu Mitadd48c082011-08-03 16:21:01 -070031 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;
Jens Axboe581d4e22008-09-14 05:56:33 -070035}
36
37late_initcall(fail_io_timeout_debugfs);
38
39ssize_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
48ssize_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
Jens Axboe242f9dc2008-09-14 05:55:09 -070072/*
73 * blk_delete_timer - Delete/cancel timer for a given function.
74 * @req: request that we are canceling timer for
75 *
76 */
77void blk_delete_timer(struct request *req)
78{
Jens Axboe242f9dc2008-09-14 05:55:09 -070079 list_del_init(&req->timeout_list);
Jens Axboe242f9dc2008-09-14 05:55:09 -070080}
81
82static void blk_rq_timed_out(struct request *req)
83{
84 struct request_queue *q = req->q;
Hannes Reinecke80bd7182013-01-30 09:26:17 +000085 enum blk_eh_timer_return ret = BLK_EH_RESET_TIMER;
Jens Axboe242f9dc2008-09-14 05:55:09 -070086
Hannes Reinecke80bd7182013-01-30 09:26:17 +000087 if (q->rq_timed_out_fn)
88 ret = q->rq_timed_out_fn(req);
Jens Axboe242f9dc2008-09-14 05:55:09 -070089 switch (ret) {
90 case BLK_EH_HANDLED:
91 __blk_complete_request(req);
92 break;
93 case BLK_EH_RESET_TIMER:
94 blk_clear_rq_complete(req);
95 blk_add_timer(req);
96 break;
97 case BLK_EH_NOT_HANDLED:
98 /*
99 * LLD handles this for now but in the future
100 * we can send a request msg to abort the command
101 * and we can move more of the generic scsi eh code to
102 * the blk layer.
103 */
104 break;
105 default:
106 printk(KERN_ERR "block: bad eh return: %d\n", ret);
107 break;
108 }
109}
110
111void blk_rq_timed_out_timer(unsigned long data)
112{
113 struct request_queue *q = (struct request_queue *) data;
malahal@us.ibm.com565e4112008-10-30 08:51:58 +0100114 unsigned long flags, next = 0;
Jens Axboe242f9dc2008-09-14 05:55:09 -0700115 struct request *rq, *tmp;
Richard Kennedya534dbe2010-04-14 20:54:03 +0200116 int next_set = 0;
Jens Axboe242f9dc2008-09-14 05:55:09 -0700117
118 spin_lock_irqsave(q->queue_lock, flags);
119
120 list_for_each_entry_safe(rq, tmp, &q->timeout_list, timeout_list) {
121 if (time_after_eq(jiffies, rq->deadline)) {
122 list_del_init(&rq->timeout_list);
123
124 /*
125 * Check if we raced with end io completion
126 */
127 if (blk_mark_rq_complete(rq))
128 continue;
129 blk_rq_timed_out(rq);
Richard Kennedya534dbe2010-04-14 20:54:03 +0200130 } else if (!next_set || time_after(next, rq->deadline)) {
Tejun Heo2eef33e2009-04-23 11:05:18 +0900131 next = rq->deadline;
Richard Kennedya534dbe2010-04-14 20:54:03 +0200132 next_set = 1;
133 }
Jens Axboe242f9dc2008-09-14 05:55:09 -0700134 }
135
Richard Kennedya534dbe2010-04-14 20:54:03 +0200136 if (next_set)
Alan Stern7838c152008-11-06 08:42:49 +0100137 mod_timer(&q->timeout, round_jiffies_up(next));
Jens Axboe242f9dc2008-09-14 05:55:09 -0700138
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 */
151void blk_abort_request(struct request *req)
152{
Jens Axboe7ba1fba2008-09-16 09:54:11 -0700153 if (blk_mark_rq_complete(req))
154 return;
Jens Axboe242f9dc2008-09-14 05:55:09 -0700155 blk_delete_timer(req);
156 blk_rq_timed_out(req);
157}
158EXPORT_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 */
168void 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
Tejun Heo2eef33e2009-04-23 11:05:18 +0900179 /*
180 * Some LLDs, like scsi, peek at the timeout to prevent a
181 * command from being retried forever.
182 */
183 if (!req->timeout)
Jens Axboe242f9dc2008-09-14 05:55:09 -0700184 req->timeout = q->rq_timeout;
Tejun Heo2eef33e2009-04-23 11:05:18 +0900185
186 req->deadline = jiffies + req->timeout;
Jens Axboe242f9dc2008-09-14 05:55:09 -0700187 list_add_tail(&req->timeout_list, &q->timeout_list);
188
189 /*
190 * If the timer isn't already pending or this timeout is earlier
Alan Stern7838c152008-11-06 08:42:49 +0100191 * than an existing one, modify the timer. Round up to next nearest
Jens Axboe242f9dc2008-09-14 05:55:09 -0700192 * second.
193 */
Alan Stern7838c152008-11-06 08:42:49 +0100194 expiry = round_jiffies_up(req->deadline);
Jens Axboe242f9dc2008-09-14 05:55:09 -0700195
196 if (!timer_pending(&q->timeout) ||
197 time_before(expiry, q->timeout.expires))
198 mod_timer(&q->timeout, expiry);
199}
Mike Anderson11914a52008-09-13 20:31:27 +0200200