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,
63 rq->mq_hctx->flags & BLK_MQ_F_BLOCKING &&
64 rq->cmd_flags & REQ_NOWAIT);
65
66 }
67 EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
68
blk_rq_is_poll(struct request * rq)69 static bool blk_rq_is_poll(struct request *rq)
70 {
71 return rq->mq_hctx && rq->mq_hctx->type == HCTX_TYPE_POLL;
72 }
73
blk_rq_poll_completion(struct request * rq,struct completion * wait)74 static void blk_rq_poll_completion(struct request *rq, struct completion *wait)
75 {
76 do {
77 blk_poll(rq->q, request_to_qc_t(rq->mq_hctx, rq), true);
78 cond_resched();
79 } while (!completion_done(wait));
80 }
81
82 /**
83 * blk_execute_rq - insert a request into queue for execution
84 * @bd_disk: matching gendisk
85 * @rq: request to insert
86 * @at_head: insert request at head or tail of queue
87 *
88 * Description:
89 * Insert a fully prepared request at the back of the I/O scheduler queue
90 * for execution and wait for completion.
91 * Return: The blk_status_t result provided to blk_mq_end_request().
92 */
blk_execute_rq(struct gendisk * bd_disk,struct request * rq,int at_head)93 blk_status_t blk_execute_rq(struct gendisk *bd_disk, struct request *rq, int at_head)
94 {
95 DECLARE_COMPLETION_ONSTACK(wait);
96 unsigned long hang_check;
97
98 rq->end_io_data = &wait;
99 blk_execute_rq_nowait(bd_disk, rq, at_head, blk_end_sync_rq);
100
101 /* Prevent hang_check timer from firing at us during very long I/O */
102 hang_check = sysctl_hung_task_timeout_secs;
103
104 if (blk_rq_is_poll(rq))
105 blk_rq_poll_completion(rq, &wait);
106 else if (hang_check)
107 while (!wait_for_completion_io_timeout(&wait, hang_check * (HZ/2)));
108 else
109 wait_for_completion_io(&wait);
110
111 return (blk_status_t)(uintptr_t)rq->end_io_data;
112 }
113 EXPORT_SYMBOL(blk_execute_rq);
114