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v3.1
 
  1/*
  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>
  7#include <linux/fault-inject.h>
  8
  9#include "blk.h"
 
 10
 11#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	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;
 35}
 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
 72/*
 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{
 79	list_del_init(&req->timeout_list);
 
 
 
 
 
 
 80}
 
 81
 82static void blk_rq_timed_out(struct request *req)
 83{
 84	struct request_queue *q = req->q;
 85	enum blk_eh_timer_return ret;
 86
 87	ret = q->rq_timed_out_fn(req);
 88	switch (ret) {
 89	case BLK_EH_HANDLED:
 90		__blk_complete_request(req);
 91		break;
 92	case BLK_EH_RESET_TIMER:
 93		blk_clear_rq_complete(req);
 94		blk_add_timer(req);
 95		break;
 96	case BLK_EH_NOT_HANDLED:
 97		/*
 98		 * LLD handles this for now but in the future
 99		 * we can send a request msg to abort the command
100		 * and we can move more of the generic scsi eh code to
101		 * the blk layer.
102		 */
103		break;
104	default:
105		printk(KERN_ERR "block: bad eh return: %d\n", ret);
106		break;
107	}
108}
109
110void blk_rq_timed_out_timer(unsigned long data)
111{
112	struct request_queue *q = (struct request_queue *) data;
113	unsigned long flags, next = 0;
114	struct request *rq, *tmp;
115	int next_set = 0;
116
117	spin_lock_irqsave(q->queue_lock, flags);
118
119	list_for_each_entry_safe(rq, tmp, &q->timeout_list, timeout_list) {
120		if (time_after_eq(jiffies, rq->deadline)) {
121			list_del_init(&rq->timeout_list);
122
123			/*
124			 * Check if we raced with end io completion
125			 */
126			if (blk_mark_rq_complete(rq))
127				continue;
128			blk_rq_timed_out(rq);
129		} else if (!next_set || time_after(next, rq->deadline)) {
130			next = rq->deadline;
131			next_set = 1;
132		}
133	}
134
135	if (next_set)
136		mod_timer(&q->timeout, round_jiffies_up(next));
137
138	spin_unlock_irqrestore(q->queue_lock, flags);
 
 
 
 
 
139}
140
141/**
142 * blk_abort_request -- Request request recovery for the specified command
143 * @req:	pointer to the request of interest
144 *
145 * This function requests that the block layer start recovery for the
146 * request by deleting the timer and calling the q's timeout function.
147 * LLDDs who implement their own error recovery MAY ignore the timeout
148 * event if they generated blk_abort_req. Must hold queue lock.
149 */
150void blk_abort_request(struct request *req)
151{
152	if (blk_mark_rq_complete(req))
153		return;
154	blk_delete_timer(req);
155	blk_rq_timed_out(req);
 
 
 
156}
157EXPORT_SYMBOL_GPL(blk_abort_request);
158
159/**
160 * blk_add_timer - Start timeout timer for a single request
161 * @req:	request that is about to start running.
162 *
163 * Notes:
164 *    Each request has its own timer, and as it is added to the queue, we
165 *    set up the timer. When the request completes, we cancel the timer.
166 */
167void blk_add_timer(struct request *req)
168{
169	struct request_queue *q = req->q;
170	unsigned long expiry;
171
172	if (!q->rq_timed_out_fn)
173		return;
174
175	BUG_ON(!list_empty(&req->timeout_list));
176	BUG_ON(test_bit(REQ_ATOM_COMPLETE, &req->atomic_flags));
177
178	/*
179	 * Some LLDs, like scsi, peek at the timeout to prevent a
180	 * command from being retried forever.
181	 */
182	if (!req->timeout)
183		req->timeout = q->rq_timeout;
184
185	req->deadline = jiffies + req->timeout;
186	list_add_tail(&req->timeout_list, &q->timeout_list);
 
 
187
188	/*
189	 * If the timer isn't already pending or this timeout is earlier
190	 * than an existing one, modify the timer. Round up to next nearest
191	 * second.
192	 */
193	expiry = round_jiffies_up(req->deadline);
194
195	if (!timer_pending(&q->timeout) ||
196	    time_before(expiry, q->timeout.expires))
197		mod_timer(&q->timeout, expiry);
198}
199
200/**
201 * blk_abort_queue -- Abort all request on given queue
202 * @queue:	pointer to queue
203 *
204 */
205void blk_abort_queue(struct request_queue *q)
206{
207	unsigned long flags;
208	struct request *rq, *tmp;
209	LIST_HEAD(list);
210
211	/*
212	 * Not a request based block device, nothing to abort
213	 */
214	if (!q->request_fn)
215		return;
216
217	spin_lock_irqsave(q->queue_lock, flags);
218
219	elv_abort_queue(q);
220
221	/*
222	 * Splice entries to local list, to avoid deadlocking if entries
223	 * get readded to the timeout list by error handling
224	 */
225	list_splice_init(&q->timeout_list, &list);
226
227	list_for_each_entry_safe(rq, tmp, &list, timeout_list)
228		blk_abort_request(rq);
229
230	/*
231	 * Occasionally, blk_abort_request() will return without
232	 * deleting the element from the list. Make sure we add those back
233	 * instead of leaving them on the local stack list.
234	 */
235	list_splice(&list, &q->timeout_list);
236
237	spin_unlock_irqrestore(q->queue_lock, flags);
238
239}
240EXPORT_SYMBOL_GPL(blk_abort_queue);
v6.13.7
  1// SPDX-License-Identifier: GPL-2.0
  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>
  8#include <linux/fault-inject.h>
  9
 10#include "blk.h"
 11#include "blk-mq.h"
 12
 13#ifdef CONFIG_FAIL_IO_TIMEOUT
 14
 15static DECLARE_FAULT_ATTR(fail_io_timeout);
 16
 17static 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
 23bool __blk_should_fake_timeout(struct request_queue *q)
 24{
 
 
 
 25	return should_fail(&fail_io_timeout, 1);
 26}
 27EXPORT_SYMBOL_GPL(__blk_should_fake_timeout);
 28
 29static int __init fail_io_timeout_debugfs(void)
 30{
 31	struct dentry *dir = fault_create_debugfs_attr("fail_io_timeout",
 32						NULL, &fail_io_timeout);
 33
 34	return PTR_ERR_OR_ZERO(dir);
 35}
 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		if (val)
 60			blk_queue_flag_set(QUEUE_FLAG_FAIL_IO, q);
 61		else
 62			blk_queue_flag_clear(QUEUE_FLAG_FAIL_IO, q);
 
 63	}
 64
 65	return count;
 66}
 67
 68#endif /* CONFIG_FAIL_IO_TIMEOUT */
 69
 70/**
 71 * blk_abort_request - Request recovery for the specified command
 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
 77 * event if they generated blk_abort_request.
 78 */
 79void blk_abort_request(struct request *req)
 80{
 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	 */
 86	WRITE_ONCE(req->deadline, jiffies);
 87	kblockd_schedule_work(&req->q->timeout_work);
 88}
 89EXPORT_SYMBOL_GPL(blk_abort_request);
 90
 91static unsigned long blk_timeout_mask __read_mostly;
 
 
 
 92
 93static int __init blk_timeout_init(void)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 94{
 95	blk_timeout_mask = roundup_pow_of_two(HZ) - 1;
 96	return 0;
 97}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 98
 99late_initcall(blk_timeout_init);
 
100
101/*
102 * Just a rough estimate, we don't care about specific values for timeouts.
103 */
104static inline unsigned long blk_round_jiffies(unsigned long j)
105{
106	return (j + blk_timeout_mask) + 1;
107}
108
109unsigned long blk_rq_timeout(unsigned long timeout)
 
 
 
 
 
 
 
 
 
110{
111	unsigned long maxt;
112
113	maxt = blk_round_jiffies(jiffies + BLK_MAX_TIMEOUT);
114	if (time_after(timeout, maxt))
115		timeout = maxt;
116
117	return timeout;
118}
 
119
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 */
128void blk_add_timer(struct request *req)
129{
130	struct request_queue *q = req->q;
131	unsigned long expiry;
132
 
 
 
 
 
 
133	/*
134	 * Some LLDs, like scsi, peek at the timeout to prevent a
135	 * command from being retried forever.
136	 */
137	if (!req->timeout)
138		req->timeout = q->rq_timeout;
139
140	req->rq_flags &= ~RQF_TIMED_OUT;
141
142	expiry = jiffies + req->timeout;
143	WRITE_ONCE(req->deadline, expiry);
144
145	/*
146	 * If the timer isn't already pending or this timeout is earlier
147	 * than an existing one, modify the timer. Round up to next nearest
148	 * second.
149	 */
150	expiry = blk_rq_timeout(blk_round_jiffies(expiry));
151
152	if (!timer_pending(&q->timeout) ||
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		 */
163		if (!timer_pending(&q->timeout) || (diff >= HZ / 2))
164			mod_timer(&q->timeout, expiry);
165	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
166
167}