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