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 */
20 static 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 */
48 void 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 }
64 EXPORT_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 */
77 void 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 }
93 EXPORT_SYMBOL(blk_execute_rq);