Christoph Hellwig | 3dcf60bc | 2019-04-30 14:42:43 -0400 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 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> |
Jens Axboe | 581d4e2 | 2008-09-14 05:56:33 -0700 | [diff] [blame] | 8 | #include <linux/fault-inject.h> |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 9 | |
| 10 | #include "blk.h" |
Christoph Hellwig | 9041583 | 2014-09-22 10:21:48 -0600 | [diff] [blame] | 11 | #include "blk-mq.h" |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 12 | |
Jens Axboe | 581d4e2 | 2008-09-14 05:56:33 -0700 | [diff] [blame] | 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 | |
| 23 | int blk_should_fake_timeout(struct request_queue *q) |
| 24 | { |
| 25 | if (!test_bit(QUEUE_FLAG_FAIL_IO, &q->queue_flags)) |
| 26 | return 0; |
| 27 | |
| 28 | return should_fail(&fail_io_timeout, 1); |
| 29 | } |
| 30 | |
| 31 | static int __init fail_io_timeout_debugfs(void) |
| 32 | { |
Akinobu Mita | dd48c08 | 2011-08-03 16:21:01 -0700 | [diff] [blame] | 33 | struct dentry *dir = fault_create_debugfs_attr("fail_io_timeout", |
| 34 | NULL, &fail_io_timeout); |
| 35 | |
Duan Jiong | 8616ebb | 2013-11-06 15:55:44 +0800 | [diff] [blame] | 36 | return PTR_ERR_OR_ZERO(dir); |
Jens Axboe | 581d4e2 | 2008-09-14 05:56:33 -0700 | [diff] [blame] | 37 | } |
| 38 | |
| 39 | late_initcall(fail_io_timeout_debugfs); |
| 40 | |
| 41 | ssize_t part_timeout_show(struct device *dev, struct device_attribute *attr, |
| 42 | char *buf) |
| 43 | { |
| 44 | struct gendisk *disk = dev_to_disk(dev); |
| 45 | int set = test_bit(QUEUE_FLAG_FAIL_IO, &disk->queue->queue_flags); |
| 46 | |
| 47 | return sprintf(buf, "%d\n", set != 0); |
| 48 | } |
| 49 | |
| 50 | ssize_t part_timeout_store(struct device *dev, struct device_attribute *attr, |
| 51 | const char *buf, size_t count) |
| 52 | { |
| 53 | struct gendisk *disk = dev_to_disk(dev); |
| 54 | int val; |
| 55 | |
| 56 | if (count) { |
| 57 | struct request_queue *q = disk->queue; |
| 58 | char *p = (char *) buf; |
| 59 | |
| 60 | val = simple_strtoul(p, &p, 10); |
Jens Axboe | 581d4e2 | 2008-09-14 05:56:33 -0700 | [diff] [blame] | 61 | if (val) |
Bart Van Assche | 8814ce8 | 2018-03-07 17:10:04 -0800 | [diff] [blame] | 62 | blk_queue_flag_set(QUEUE_FLAG_FAIL_IO, q); |
Jens Axboe | 581d4e2 | 2008-09-14 05:56:33 -0700 | [diff] [blame] | 63 | else |
Bart Van Assche | 8814ce8 | 2018-03-07 17:10:04 -0800 | [diff] [blame] | 64 | blk_queue_flag_clear(QUEUE_FLAG_FAIL_IO, q); |
Jens Axboe | 581d4e2 | 2008-09-14 05:56:33 -0700 | [diff] [blame] | 65 | } |
| 66 | |
| 67 | return count; |
| 68 | } |
| 69 | |
| 70 | #endif /* CONFIG_FAIL_IO_TIMEOUT */ |
| 71 | |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 72 | /** |
| 73 | * blk_abort_request -- Request request recovery for the specified command |
| 74 | * @req: pointer to the request of interest |
| 75 | * |
| 76 | * This function requests that the block layer start recovery for the |
| 77 | * request by deleting the timer and calling the q's timeout function. |
| 78 | * LLDDs who implement their own error recovery MAY ignore the timeout |
Christoph Hellwig | 39795d6 | 2018-11-14 17:02:06 +0100 | [diff] [blame] | 79 | * event if they generated blk_abort_request. |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 80 | */ |
| 81 | void blk_abort_request(struct request *req) |
| 82 | { |
Jens Axboe | 4316b79 | 2018-10-29 10:25:07 -0600 | [diff] [blame] | 83 | /* |
| 84 | * All we need to ensure is that timeout scan takes place |
| 85 | * immediately and that scan sees the new timeout value. |
| 86 | * No need for fancy synchronizations. |
| 87 | */ |
Christoph Hellwig | 079076b | 2018-11-14 17:02:05 +0100 | [diff] [blame] | 88 | WRITE_ONCE(req->deadline, jiffies); |
Jens Axboe | 4316b79 | 2018-10-29 10:25:07 -0600 | [diff] [blame] | 89 | kblockd_schedule_work(&req->q->timeout_work); |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 90 | } |
| 91 | EXPORT_SYMBOL_GPL(blk_abort_request); |
| 92 | |
Jens Axboe | 0d2602c | 2014-05-13 15:10:52 -0600 | [diff] [blame] | 93 | unsigned long blk_rq_timeout(unsigned long timeout) |
| 94 | { |
| 95 | unsigned long maxt; |
| 96 | |
| 97 | maxt = round_jiffies_up(jiffies + BLK_MAX_TIMEOUT); |
| 98 | if (time_after(timeout, maxt)) |
| 99 | timeout = maxt; |
| 100 | |
| 101 | return timeout; |
| 102 | } |
| 103 | |
Christoph Hellwig | c4a634f | 2014-04-25 14:14:48 +0200 | [diff] [blame] | 104 | /** |
| 105 | * blk_add_timer - Start timeout timer for a single request |
| 106 | * @req: request that is about to start running. |
| 107 | * |
| 108 | * Notes: |
| 109 | * Each request has its own timer, and as it is added to the queue, we |
| 110 | * set up the timer. When the request completes, we cancel the timer. |
| 111 | */ |
| 112 | void blk_add_timer(struct request *req) |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 113 | { |
| 114 | struct request_queue *q = req->q; |
| 115 | unsigned long expiry; |
| 116 | |
Tejun Heo | 2eef33e | 2009-04-23 11:05:18 +0900 | [diff] [blame] | 117 | /* |
| 118 | * Some LLDs, like scsi, peek at the timeout to prevent a |
| 119 | * command from being retried forever. |
| 120 | */ |
| 121 | if (!req->timeout) |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 122 | req->timeout = q->rq_timeout; |
Tejun Heo | 2eef33e | 2009-04-23 11:05:18 +0900 | [diff] [blame] | 123 | |
Bart Van Assche | f5e350f | 2018-06-22 13:18:09 -0700 | [diff] [blame] | 124 | req->rq_flags &= ~RQF_TIMED_OUT; |
Christoph Hellwig | 079076b | 2018-11-14 17:02:05 +0100 | [diff] [blame] | 125 | |
| 126 | expiry = jiffies + req->timeout; |
| 127 | WRITE_ONCE(req->deadline, expiry); |
Jens Axboe | 3b627a3 | 2015-11-24 15:58:53 -0700 | [diff] [blame] | 128 | |
| 129 | /* |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 130 | * If the timer isn't already pending or this timeout is earlier |
Alan Stern | 7838c15 | 2008-11-06 08:42:49 +0100 | [diff] [blame] | 131 | * than an existing one, modify the timer. Round up to next nearest |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 132 | * second. |
| 133 | */ |
Christoph Hellwig | 079076b | 2018-11-14 17:02:05 +0100 | [diff] [blame] | 134 | expiry = blk_rq_timeout(round_jiffies_up(expiry)); |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 135 | |
| 136 | if (!timer_pending(&q->timeout) || |
Jens Axboe | f793aa5 | 2014-04-16 11:36:54 -0600 | [diff] [blame] | 137 | time_before(expiry, q->timeout.expires)) { |
| 138 | unsigned long diff = q->timeout.expires - expiry; |
| 139 | |
| 140 | /* |
| 141 | * Due to added timer slack to group timers, the timer |
| 142 | * will often be a little in front of what we asked for. |
| 143 | * So apply some tolerance here too, otherwise we keep |
| 144 | * modifying the timer because expires for value X |
| 145 | * will be X + something. |
| 146 | */ |
Jens Axboe | c7bca41 | 2014-05-30 15:41:39 -0600 | [diff] [blame] | 147 | if (!timer_pending(&q->timeout) || (diff >= HZ / 2)) |
Jens Axboe | f793aa5 | 2014-04-16 11:36:54 -0600 | [diff] [blame] | 148 | mod_timer(&q->timeout, expiry); |
| 149 | } |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 150 | |
| 151 | } |