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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 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);
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 __blk_end_request_all(rq, BLK_STS_IOERR);
73 spin_unlock_irq(q->queue_lock);
74 return;
75 }
76
77 __elv_add_request(q, rq, where);
78 __blk_run_queue(q);
79 spin_unlock_irq(q->queue_lock);
80}
81EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
82
83/**
84 * blk_execute_rq - insert a request into queue for execution
85 * @q: queue to insert the request in
86 * @bd_disk: matching gendisk
87 * @rq: request to insert
88 * @at_head: insert request at head or tail of queue
89 *
90 * Description:
91 * Insert a fully prepared request at the back of the I/O scheduler queue
92 * for execution and wait for completion.
93 */
94void blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk,
95 struct request *rq, int at_head)
96{
97 DECLARE_COMPLETION_ONSTACK(wait);
98 unsigned long hang_check;
99
100 rq->end_io_data = &wait;
101 blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
102
103 /* Prevent hang_check timer from firing at us during very long I/O */
104 hang_check = sysctl_hung_task_timeout_secs;
105 if (hang_check)
106 while (!wait_for_completion_io_timeout(&wait, hang_check * (HZ/2)));
107 else
108 wait_for_completion_io(&wait);
109}
110EXPORT_SYMBOL(blk_execute_rq);
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
9#include "blk.h"
10
11/*
12 * for max sense size
13 */
14#include <scsi/scsi_cmnd.h>
15
16/**
17 * blk_end_sync_rq - executes a completion event on a request
18 * @rq: request to complete
19 * @error: end I/O status of the request
20 */
21static void blk_end_sync_rq(struct request *rq, int error)
22{
23 struct completion *waiting = rq->end_io_data;
24
25 rq->end_io_data = NULL;
26 __blk_put_request(rq->q, rq);
27
28 /*
29 * complete last, if this is a stack request the process (and thus
30 * the rq pointer) could be invalid right after this complete()
31 */
32 complete(waiting);
33}
34
35/**
36 * blk_execute_rq_nowait - insert a request into queue for execution
37 * @q: queue to insert the request in
38 * @bd_disk: matching gendisk
39 * @rq: request to insert
40 * @at_head: insert request at head or tail of queue
41 * @done: I/O completion handler
42 *
43 * Description:
44 * Insert a fully prepared request at the back of the I/O scheduler queue
45 * for execution. Don't wait for completion.
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 if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) {
54 rq->errors = -ENXIO;
55 if (rq->end_io)
56 rq->end_io(rq, rq->errors);
57 return;
58 }
59
60 rq->rq_disk = bd_disk;
61 rq->end_io = done;
62 WARN_ON(irqs_disabled());
63 spin_lock_irq(q->queue_lock);
64 __elv_add_request(q, rq, where);
65 __blk_run_queue(q);
66 /* the queue is stopped so it won't be run */
67 if (rq->cmd_type == REQ_TYPE_PM_RESUME)
68 q->request_fn(q);
69 spin_unlock_irq(q->queue_lock);
70}
71EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
72
73/**
74 * blk_execute_rq - insert a request into queue for execution
75 * @q: queue to insert the request in
76 * @bd_disk: matching gendisk
77 * @rq: request to insert
78 * @at_head: insert request at head or tail of queue
79 *
80 * Description:
81 * Insert a fully prepared request at the back of the I/O scheduler queue
82 * for execution and wait for completion.
83 */
84int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk,
85 struct request *rq, int at_head)
86{
87 DECLARE_COMPLETION_ONSTACK(wait);
88 char sense[SCSI_SENSE_BUFFERSIZE];
89 int err = 0;
90 unsigned long hang_check;
91
92 /*
93 * we need an extra reference to the request, so we can look at
94 * it after io completion
95 */
96 rq->ref_count++;
97
98 if (!rq->sense) {
99 memset(sense, 0, sizeof(sense));
100 rq->sense = sense;
101 rq->sense_len = 0;
102 }
103
104 rq->end_io_data = &wait;
105 blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
106
107 /* Prevent hang_check timer from firing at us during very long I/O */
108 hang_check = sysctl_hung_task_timeout_secs;
109 if (hang_check)
110 while (!wait_for_completion_timeout(&wait, hang_check * (HZ/2)));
111 else
112 wait_for_completion(&wait);
113
114 if (rq->errors)
115 err = -EIO;
116
117 return err;
118}
119EXPORT_SYMBOL(blk_execute_rq);