tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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, int 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 int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
52
53 WARN_ON(irqs_disabled());
54 WARN_ON(!blk_rq_is_passthrough(rq));
55
56 rq->rq_disk = bd_disk;
57 rq->end_io = done;
58
59 /*
60 * don't check dying flag for MQ because the request won't
61 * be reused after dying flag is set
62 */
63 if (q->mq_ops) {
64 blk_mq_sched_insert_request(rq, at_head, true, false, false);
65 return;
66 }
67
68 spin_lock_irq(q->queue_lock);
69
70 if (unlikely(blk_queue_dying(q))) {
71 rq->rq_flags |= RQF_QUIET;
72 rq->errors = -ENXIO;
73 __blk_end_request_all(rq, rq->errors);
74 spin_unlock_irq(q->queue_lock);
75 return;
76 }
77
78 __elv_add_request(q, rq, where);
79 __blk_run_queue(q);
80 spin_unlock_irq(q->queue_lock);
81}
82EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
83
84/**
85 * blk_execute_rq - insert a request into queue for execution
86 * @q: queue to insert the request in
87 * @bd_disk: matching gendisk
88 * @rq: request to insert
89 * @at_head: insert request at head or tail of queue
90 *
91 * Description:
92 * Insert a fully prepared request at the back of the I/O scheduler queue
93 * for execution and wait for completion.
94 */
95int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk,
96 struct request *rq, int at_head)
97{
98 DECLARE_COMPLETION_ONSTACK(wait);
99 int err = 0;
100 unsigned long hang_check;
101
102 rq->end_io_data = &wait;
103 blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
104
105 /* Prevent hang_check timer from firing at us during very long I/O */
106 hang_check = sysctl_hung_task_timeout_secs;
107 if (hang_check)
108 while (!wait_for_completion_io_timeout(&wait, hang_check * (HZ/2)));
109 else
110 wait_for_completion_io(&wait);
111
112 if (rq->errors)
113 err = -EIO;
114
115 return err;
116}
117EXPORT_SYMBOL(blk_execute_rq);