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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 | */ | |
19 | static 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 | */ | |
47 | void 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 | } | |
81 | EXPORT_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 | */ | |
94 | void 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 | } | |
110 | EXPORT_SYMBOL(blk_execute_rq); |