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 */
blk_end_sync_rq(struct request * rq,blk_status_t error)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 = (void *)(uintptr_t)error;
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 to I/O scheduler for execution
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 */
blk_execute_rq_nowait(struct gendisk * bd_disk,struct request * rq,int at_head,rq_end_io_fn * done)47 void blk_execute_rq_nowait(struct gendisk *bd_disk, struct request *rq,
48 int at_head, rq_end_io_fn *done)
49 {
50 WARN_ON(irqs_disabled());
51 WARN_ON(!blk_rq_is_passthrough(rq));
52
53 rq->rq_disk = bd_disk;
54 rq->end_io = done;
55
56 blk_account_io_start(rq);
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
blk_rq_is_poll(struct request * rq)66 static bool blk_rq_is_poll(struct request *rq)
67 {
68 return rq->mq_hctx && rq->mq_hctx->type == HCTX_TYPE_POLL;
69 }
70
blk_rq_poll_completion(struct request * rq,struct completion * wait)71 static void blk_rq_poll_completion(struct request *rq, struct completion *wait)
72 {
73 do {
74 blk_poll(rq->q, request_to_qc_t(rq->mq_hctx, rq), true);
75 cond_resched();
76 } while (!completion_done(wait));
77 }
78
79 /**
80 * blk_execute_rq - insert a request into queue for execution
81 * @bd_disk: matching gendisk
82 * @rq: request to insert
83 * @at_head: insert request at head or tail of queue
84 *
85 * Description:
86 * Insert a fully prepared request at the back of the I/O scheduler queue
87 * for execution and wait for completion.
88 * Return: The blk_status_t result provided to blk_mq_end_request().
89 */
blk_execute_rq(struct gendisk * bd_disk,struct request * rq,int at_head)90 blk_status_t blk_execute_rq(struct gendisk *bd_disk, struct request *rq, int at_head)
91 {
92 DECLARE_COMPLETION_ONSTACK(wait);
93 unsigned long hang_check;
94
95 rq->end_io_data = &wait;
96 blk_execute_rq_nowait(bd_disk, rq, at_head, blk_end_sync_rq);
97
98 /* Prevent hang_check timer from firing at us during very long I/O */
99 hang_check = sysctl_hung_task_timeout_secs;
100
101 if (blk_rq_is_poll(rq))
102 blk_rq_poll_completion(rq, &wait);
103 else if (hang_check)
104 while (!wait_for_completion_io_timeout(&wait, hang_check * (HZ/2)));
105 else
106 wait_for_completion_io(&wait);
107
108 return (blk_status_t)(uintptr_t)rq->end_io_data;
109 }
110 EXPORT_SYMBOL(blk_execute_rq);
111
