1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Functions related to setting various queue properties from drivers
 4 */
 5#include <linux/kernel.h>
 6#include <linux/module.h>
 7#include <linux/bio.h>
 8#include <linux/blkdev.h>
 9#include <linux/blk-mq.h>
10#include <linux/sched/sysctl.h>
11
12#include "blk.h"
13#include "blk-mq-sched.h"
14
15/**
16 * blk_end_sync_rq - executes a completion event on a request
17 * @rq: request to complete
18 * @error: end I/O status of the request
19 */
20static void blk_end_sync_rq(struct request *rq, blk_status_t error)
21{
22	struct completion *waiting = rq->end_io_data;
23
24	rq->end_io_data = NULL;
25
26	/*
27	 * complete last, if this is a stack request the process (and thus
28	 * the rq pointer) could be invalid right after this complete()
29	 */
30	complete(waiting);
31}
32
33/**
34 * blk_execute_rq_nowait - insert a request into queue for execution
35 * @q:		queue to insert the request in
36 * @bd_disk:	matching gendisk
37 * @rq:		request to insert
38 * @at_head:    insert request at head or tail of queue
39 * @done:	I/O completion handler
40 *
41 * Description:
42 *    Insert a fully prepared request at the back of the I/O scheduler queue
43 *    for execution.  Don't wait for completion.
44 *
45 * Note:
46 *    This function will invoke @done directly if the queue is dead.
47 */
48void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
49			   struct request *rq, int at_head,
50			   rq_end_io_fn *done)
51{
52	WARN_ON(irqs_disabled());
53	WARN_ON(!blk_rq_is_passthrough(rq));
54
55	rq->rq_disk = bd_disk;
56	rq->end_io = done;
57
58	/*
59	 * don't check dying flag for MQ because the request won't
60	 * be reused after dying flag is set
61	 */
62	blk_mq_sched_insert_request(rq, at_head, true, false);
63}
64EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
65
66/**
67 * blk_execute_rq - insert a request into queue for execution
68 * @q:		queue to insert the request in
69 * @bd_disk:	matching gendisk
70 * @rq:		request to insert
71 * @at_head:    insert request at head or tail of queue
72 *
73 * Description:
74 *    Insert a fully prepared request at the back of the I/O scheduler queue
75 *    for execution and wait for completion.
76 */
77void blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk,
78		   struct request *rq, int at_head)
79{
80	DECLARE_COMPLETION_ONSTACK(wait);
81	unsigned long hang_check;
82
83	rq->end_io_data = &wait;
84	blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
85
86	/* Prevent hang_check timer from firing at us during very long I/O */
87	hang_check = sysctl_hung_task_timeout_secs;
88	if (hang_check)
89		while (!wait_for_completion_io_timeout(&wait, hang_check * (HZ/2)));
90	else
91		wait_for_completion_io(&wait);
92}
93EXPORT_SYMBOL(blk_execute_rq);