Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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 rq->rq_disk = bd_disk;
54 rq->cmd_flags |= REQ_NOMERGE;
55 rq->end_io = done;
56 WARN_ON(irqs_disabled());
57 spin_lock_irq(q->queue_lock);
58 __elv_add_request(q, rq, where, 1);
59 __generic_unplug_device(q);
60 /* the queue is stopped so it won't be plugged+unplugged */
61 if (blk_pm_resume_request(rq))
62 q->request_fn(q);
63 spin_unlock_irq(q->queue_lock);
64}
65EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
66
67/**
68 * blk_execute_rq - insert a request into queue for execution
69 * @q: queue to insert the request in
70 * @bd_disk: matching gendisk
71 * @rq: request to insert
72 * @at_head: insert request at head or tail of queue
73 *
74 * Description:
75 * Insert a fully prepared request at the back of the I/O scheduler queue
76 * for execution and wait for completion.
77 */
78int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk,
79 struct request *rq, int at_head)
80{
81 DECLARE_COMPLETION_ONSTACK(wait);
82 char sense[SCSI_SENSE_BUFFERSIZE];
83 int err = 0;
84
85 /*
86 * we need an extra reference to the request, so we can look at
87 * it after io completion
88 */
89 rq->ref_count++;
90
91 if (!rq->sense) {
92 memset(sense, 0, sizeof(sense));
93 rq->sense = sense;
94 rq->sense_len = 0;
95 }
96
97 rq->end_io_data = &wait;
98 blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
99 wait_for_completion(&wait);
100
101 if (rq->errors)
102 err = -EIO;
103
104 return err;
105}
106EXPORT_SYMBOL(blk_execute_rq);