Commit | Line | Data |
---|---|---|
3dcf60bc | 1 | // SPDX-License-Identifier: GPL-2.0 |
242f9dcb JA |
2 | /* |
3 | * Functions related to generic timeout handling of requests. | |
4 | */ | |
5 | #include <linux/kernel.h> | |
6 | #include <linux/module.h> | |
7 | #include <linux/blkdev.h> | |
581d4e28 | 8 | #include <linux/fault-inject.h> |
242f9dcb JA |
9 | |
10 | #include "blk.h" | |
90415837 | 11 | #include "blk-mq.h" |
242f9dcb | 12 | |
581d4e28 JA |
13 | #ifdef CONFIG_FAIL_IO_TIMEOUT |
14 | ||
15 | static DECLARE_FAULT_ATTR(fail_io_timeout); | |
16 | ||
17 | static int __init setup_fail_io_timeout(char *str) | |
18 | { | |
19 | return setup_fault_attr(&fail_io_timeout, str); | |
20 | } | |
21 | __setup("fail_io_timeout=", setup_fail_io_timeout); | |
22 | ||
15f73f5b | 23 | bool __blk_should_fake_timeout(struct request_queue *q) |
581d4e28 | 24 | { |
581d4e28 JA |
25 | return should_fail(&fail_io_timeout, 1); |
26 | } | |
15f73f5b | 27 | EXPORT_SYMBOL_GPL(__blk_should_fake_timeout); |
581d4e28 JA |
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 | ||
8616ebb1 | 34 | return PTR_ERR_OR_ZERO(dir); |
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); | |
581d4e28 | 59 | if (val) |
8814ce8a | 60 | blk_queue_flag_set(QUEUE_FLAG_FAIL_IO, q); |
581d4e28 | 61 | else |
8814ce8a | 62 | blk_queue_flag_clear(QUEUE_FLAG_FAIL_IO, q); |
581d4e28 JA |
63 | } |
64 | ||
65 | return count; | |
66 | } | |
67 | ||
68 | #endif /* CONFIG_FAIL_IO_TIMEOUT */ | |
69 | ||
242f9dcb | 70 | /** |
d958e343 | 71 | * blk_abort_request - Request recovery for the specified command |
242f9dcb JA |
72 | * @req: pointer to the request of interest |
73 | * | |
74 | * This function requests that the block layer start recovery for the | |
75 | * request by deleting the timer and calling the q's timeout function. | |
76 | * LLDDs who implement their own error recovery MAY ignore the timeout | |
39795d65 | 77 | * event if they generated blk_abort_request. |
242f9dcb JA |
78 | */ |
79 | void blk_abort_request(struct request *req) | |
80 | { | |
4316b79e JA |
81 | /* |
82 | * All we need to ensure is that timeout scan takes place | |
83 | * immediately and that scan sees the new timeout value. | |
84 | * No need for fancy synchronizations. | |
85 | */ | |
079076b3 | 86 | WRITE_ONCE(req->deadline, jiffies); |
4316b79e | 87 | kblockd_schedule_work(&req->q->timeout_work); |
242f9dcb JA |
88 | } |
89 | EXPORT_SYMBOL_GPL(blk_abort_request); | |
90 | ||
9054650f JA |
91 | static unsigned long blk_timeout_mask __read_mostly; |
92 | ||
943c4d90 | 93 | static int __init blk_timeout_init(void) |
9054650f JA |
94 | { |
95 | blk_timeout_mask = roundup_pow_of_two(HZ) - 1; | |
96 | return 0; | |
97 | } | |
98 | ||
99 | late_initcall(blk_timeout_init); | |
100 | ||
101 | /* | |
102 | * Just a rough estimate, we don't care about specific values for timeouts. | |
103 | */ | |
104 | static inline unsigned long blk_round_jiffies(unsigned long j) | |
105 | { | |
106 | return (j + blk_timeout_mask) + 1; | |
107 | } | |
108 | ||
0d2602ca JA |
109 | unsigned long blk_rq_timeout(unsigned long timeout) |
110 | { | |
111 | unsigned long maxt; | |
112 | ||
9054650f | 113 | maxt = blk_round_jiffies(jiffies + BLK_MAX_TIMEOUT); |
0d2602ca JA |
114 | if (time_after(timeout, maxt)) |
115 | timeout = maxt; | |
116 | ||
117 | return timeout; | |
118 | } | |
119 | ||
c4a634f4 CH |
120 | /** |
121 | * blk_add_timer - Start timeout timer for a single request | |
122 | * @req: request that is about to start running. | |
123 | * | |
124 | * Notes: | |
125 | * Each request has its own timer, and as it is added to the queue, we | |
126 | * set up the timer. When the request completes, we cancel the timer. | |
127 | */ | |
128 | void blk_add_timer(struct request *req) | |
242f9dcb JA |
129 | { |
130 | struct request_queue *q = req->q; | |
131 | unsigned long expiry; | |
132 | ||
2eef33e4 TH |
133 | /* |
134 | * Some LLDs, like scsi, peek at the timeout to prevent a | |
135 | * command from being retried forever. | |
136 | */ | |
137 | if (!req->timeout) | |
242f9dcb | 138 | req->timeout = q->rq_timeout; |
2eef33e4 | 139 | |
f5e350f0 | 140 | req->rq_flags &= ~RQF_TIMED_OUT; |
079076b3 CH |
141 | |
142 | expiry = jiffies + req->timeout; | |
143 | WRITE_ONCE(req->deadline, expiry); | |
3b627a3f | 144 | |
242f9dcb JA |
145 | /* |
146 | * If the timer isn't already pending or this timeout is earlier | |
7838c15b | 147 | * than an existing one, modify the timer. Round up to next nearest |
242f9dcb JA |
148 | * second. |
149 | */ | |
9054650f | 150 | expiry = blk_rq_timeout(blk_round_jiffies(expiry)); |
242f9dcb JA |
151 | |
152 | if (!timer_pending(&q->timeout) || | |
f793aa53 JA |
153 | time_before(expiry, q->timeout.expires)) { |
154 | unsigned long diff = q->timeout.expires - expiry; | |
155 | ||
156 | /* | |
157 | * Due to added timer slack to group timers, the timer | |
158 | * will often be a little in front of what we asked for. | |
159 | * So apply some tolerance here too, otherwise we keep | |
160 | * modifying the timer because expires for value X | |
161 | * will be X + something. | |
162 | */ | |
c7bca418 | 163 | if (!timer_pending(&q->timeout) || (diff >= HZ / 2)) |
f793aa53 JA |
164 | mod_timer(&q->timeout, expiry); |
165 | } | |
320ae51f JA |
166 | |
167 | } |