blob: 95a09590ccfda8366f92efbee7c31f1654c11637 [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"
Jens Axboe320ae512013-10-24 09:20:05 +010010#include "blk-mq.h"
Jens Axboe242f9dc2008-09-14 05:55:09 -070011
Jens Axboe581d4e22008-09-14 05:56:33 -070012#ifdef CONFIG_FAIL_IO_TIMEOUT
13
14static DECLARE_FAULT_ATTR(fail_io_timeout);
15
16static int __init setup_fail_io_timeout(char *str)
17{
18 return setup_fault_attr(&fail_io_timeout, str);
19}
20__setup("fail_io_timeout=", setup_fail_io_timeout);
21
22int blk_should_fake_timeout(struct request_queue *q)
23{
24 if (!test_bit(QUEUE_FLAG_FAIL_IO, &q->queue_flags))
25 return 0;
26
27 return should_fail(&fail_io_timeout, 1);
28}
29
30static int __init fail_io_timeout_debugfs(void)
31{
Akinobu Mitadd48c082011-08-03 16:21:01 -070032 struct dentry *dir = fault_create_debugfs_attr("fail_io_timeout",
33 NULL, &fail_io_timeout);
34
Duan Jiong8616ebb2013-11-06 15:55:44 +080035 return PTR_ERR_OR_ZERO(dir);
Jens Axboe581d4e22008-09-14 05:56:33 -070036}
37
38late_initcall(fail_io_timeout_debugfs);
39
40ssize_t part_timeout_show(struct device *dev, struct device_attribute *attr,
41 char *buf)
42{
43 struct gendisk *disk = dev_to_disk(dev);
44 int set = test_bit(QUEUE_FLAG_FAIL_IO, &disk->queue->queue_flags);
45
46 return sprintf(buf, "%d\n", set != 0);
47}
48
49ssize_t part_timeout_store(struct device *dev, struct device_attribute *attr,
50 const char *buf, size_t count)
51{
52 struct gendisk *disk = dev_to_disk(dev);
53 int val;
54
55 if (count) {
56 struct request_queue *q = disk->queue;
57 char *p = (char *) buf;
58
59 val = simple_strtoul(p, &p, 10);
60 spin_lock_irq(q->queue_lock);
61 if (val)
62 queue_flag_set(QUEUE_FLAG_FAIL_IO, q);
63 else
64 queue_flag_clear(QUEUE_FLAG_FAIL_IO, q);
65 spin_unlock_irq(q->queue_lock);
66 }
67
68 return count;
69}
70
71#endif /* CONFIG_FAIL_IO_TIMEOUT */
72
Jens Axboe242f9dc2008-09-14 05:55:09 -070073/*
74 * blk_delete_timer - Delete/cancel timer for a given function.
75 * @req: request that we are canceling timer for
76 *
77 */
78void blk_delete_timer(struct request *req)
79{
Jens Axboe242f9dc2008-09-14 05:55:09 -070080 list_del_init(&req->timeout_list);
Jens Axboe242f9dc2008-09-14 05:55:09 -070081}
82
83static void blk_rq_timed_out(struct request *req)
84{
85 struct request_queue *q = req->q;
Hannes Reinecke80bd7182013-01-30 09:26:17 +000086 enum blk_eh_timer_return ret = BLK_EH_RESET_TIMER;
Jens Axboe242f9dc2008-09-14 05:55:09 -070087
Hannes Reinecke80bd7182013-01-30 09:26:17 +000088 if (q->rq_timed_out_fn)
89 ret = q->rq_timed_out_fn(req);
Jens Axboe242f9dc2008-09-14 05:55:09 -070090 switch (ret) {
91 case BLK_EH_HANDLED:
Jens Axboe320ae512013-10-24 09:20:05 +010092 /* Can we use req->errors here? */
93 if (q->mq_ops)
Christoph Hellwig30a91cb2014-02-10 03:24:38 -080094 __blk_mq_complete_request(req);
Jens Axboe320ae512013-10-24 09:20:05 +010095 else
96 __blk_complete_request(req);
Jens Axboe242f9dc2008-09-14 05:55:09 -070097 break;
98 case BLK_EH_RESET_TIMER:
Jens Axboe87ee7b12014-04-24 08:51:47 -060099 blk_add_timer(req);
Jeff Moyer4912aa62013-10-08 14:36:41 -0400100 blk_clear_rq_complete(req);
Jens Axboe242f9dc2008-09-14 05:55:09 -0700101 break;
102 case BLK_EH_NOT_HANDLED:
103 /*
104 * LLD handles this for now but in the future
105 * we can send a request msg to abort the command
106 * and we can move more of the generic scsi eh code to
107 * the blk layer.
108 */
109 break;
110 default:
111 printk(KERN_ERR "block: bad eh return: %d\n", ret);
112 break;
113 }
114}
115
Jens Axboe320ae512013-10-24 09:20:05 +0100116void blk_rq_check_expired(struct request *rq, unsigned long *next_timeout,
117 unsigned int *next_set)
118{
119 if (time_after_eq(jiffies, rq->deadline)) {
120 list_del_init(&rq->timeout_list);
121
122 /*
123 * Check if we raced with end io completion
124 */
125 if (!blk_mark_rq_complete(rq))
126 blk_rq_timed_out(rq);
127 } else if (!*next_set || time_after(*next_timeout, rq->deadline)) {
128 *next_timeout = rq->deadline;
129 *next_set = 1;
130 }
131}
132
Jens Axboe242f9dc2008-09-14 05:55:09 -0700133void blk_rq_timed_out_timer(unsigned long data)
134{
135 struct request_queue *q = (struct request_queue *) data;
malahal@us.ibm.com565e4112008-10-30 08:51:58 +0100136 unsigned long flags, next = 0;
Jens Axboe242f9dc2008-09-14 05:55:09 -0700137 struct request *rq, *tmp;
Richard Kennedya534dbe2010-04-14 20:54:03 +0200138 int next_set = 0;
Jens Axboe242f9dc2008-09-14 05:55:09 -0700139
140 spin_lock_irqsave(q->queue_lock, flags);
141
Jens Axboe320ae512013-10-24 09:20:05 +0100142 list_for_each_entry_safe(rq, tmp, &q->timeout_list, timeout_list)
143 blk_rq_check_expired(rq, &next, &next_set);
Jens Axboe242f9dc2008-09-14 05:55:09 -0700144
Richard Kennedya534dbe2010-04-14 20:54:03 +0200145 if (next_set)
Alan Stern7838c152008-11-06 08:42:49 +0100146 mod_timer(&q->timeout, round_jiffies_up(next));
Jens Axboe242f9dc2008-09-14 05:55:09 -0700147
148 spin_unlock_irqrestore(q->queue_lock, flags);
149}
150
151/**
152 * blk_abort_request -- Request request recovery for the specified command
153 * @req: pointer to the request of interest
154 *
155 * This function requests that the block layer start recovery for the
156 * request by deleting the timer and calling the q's timeout function.
157 * LLDDs who implement their own error recovery MAY ignore the timeout
158 * event if they generated blk_abort_req. Must hold queue lock.
159 */
160void blk_abort_request(struct request *req)
161{
Jens Axboe7ba1fba2008-09-16 09:54:11 -0700162 if (blk_mark_rq_complete(req))
163 return;
Jens Axboe242f9dc2008-09-14 05:55:09 -0700164 blk_delete_timer(req);
165 blk_rq_timed_out(req);
166}
167EXPORT_SYMBOL_GPL(blk_abort_request);
168
Jens Axboe0d2602c2014-05-13 15:10:52 -0600169unsigned long blk_rq_timeout(unsigned long timeout)
170{
171 unsigned long maxt;
172
173 maxt = round_jiffies_up(jiffies + BLK_MAX_TIMEOUT);
174 if (time_after(timeout, maxt))
175 timeout = maxt;
176
177 return timeout;
178}
179
Christoph Hellwigc4a634f2014-04-25 14:14:48 +0200180/**
181 * blk_add_timer - Start timeout timer for a single request
182 * @req: request that is about to start running.
183 *
184 * Notes:
185 * Each request has its own timer, and as it is added to the queue, we
186 * set up the timer. When the request completes, we cancel the timer.
187 */
188void blk_add_timer(struct request *req)
Jens Axboe242f9dc2008-09-14 05:55:09 -0700189{
190 struct request_queue *q = req->q;
191 unsigned long expiry;
192
193 if (!q->rq_timed_out_fn)
194 return;
195
196 BUG_ON(!list_empty(&req->timeout_list));
Jens Axboe242f9dc2008-09-14 05:55:09 -0700197
Tejun Heo2eef33e2009-04-23 11:05:18 +0900198 /*
199 * Some LLDs, like scsi, peek at the timeout to prevent a
200 * command from being retried forever.
201 */
202 if (!req->timeout)
Jens Axboe242f9dc2008-09-14 05:55:09 -0700203 req->timeout = q->rq_timeout;
Tejun Heo2eef33e2009-04-23 11:05:18 +0900204
205 req->deadline = jiffies + req->timeout;
Christoph Hellwigc4a634f2014-04-25 14:14:48 +0200206 if (!q->mq_ops)
207 list_add_tail(&req->timeout_list, &req->q->timeout_list);
Jens Axboe242f9dc2008-09-14 05:55:09 -0700208
209 /*
210 * If the timer isn't already pending or this timeout is earlier
Alan Stern7838c152008-11-06 08:42:49 +0100211 * than an existing one, modify the timer. Round up to next nearest
Jens Axboe242f9dc2008-09-14 05:55:09 -0700212 * second.
213 */
Jens Axboe0d2602c2014-05-13 15:10:52 -0600214 expiry = blk_rq_timeout(round_jiffies_up(req->deadline));
Jens Axboe242f9dc2008-09-14 05:55:09 -0700215
216 if (!timer_pending(&q->timeout) ||
Jens Axboef793aa52014-04-16 11:36:54 -0600217 time_before(expiry, q->timeout.expires)) {
218 unsigned long diff = q->timeout.expires - expiry;
219
220 /*
221 * Due to added timer slack to group timers, the timer
222 * will often be a little in front of what we asked for.
223 * So apply some tolerance here too, otherwise we keep
224 * modifying the timer because expires for value X
225 * will be X + something.
226 */
Jens Axboec7bca412014-05-30 15:41:39 -0600227 if (!timer_pending(&q->timeout) || (diff >= HZ / 2))
Jens Axboef793aa52014-04-16 11:36:54 -0600228 mod_timer(&q->timeout, expiry);
229 }
Jens Axboe320ae512013-10-24 09:20:05 +0100230
231}