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Jens Axboe86db1e22008-01-29 14:53:40 +01001/*
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>
Jens Axboe320ae512013-10-24 09:20:05 +01008#include <linux/blk-mq.h>
Clark Williamscf4aebc22013-02-07 09:46:59 -06009#include <linux/sched/sysctl.h>
Jens Axboe86db1e22008-01-29 14:53:40 +010010
11#include "blk.h"
12
13/*
14 * for max sense size
15 */
16#include <scsi/scsi_cmnd.h>
17
18/**
19 * blk_end_sync_rq - executes a completion event on a request
20 * @rq: request to complete
Randy Dunlap710027a2008-08-19 20:13:11 +020021 * @error: end I/O status of the request
Jens Axboe86db1e22008-01-29 14:53:40 +010022 */
FUJITA Tomonori681a5612008-07-15 21:21:45 +020023static void blk_end_sync_rq(struct request *rq, int error)
Jens Axboe86db1e22008-01-29 14:53:40 +010024{
25 struct completion *waiting = rq->end_io_data;
26
27 rq->end_io_data = NULL;
Jens Axboe86db1e22008-01-29 14:53:40 +010028
29 /*
30 * complete last, if this is a stack request the process (and thus
31 * the rq pointer) could be invalid right after this complete()
32 */
33 complete(waiting);
34}
Jens Axboe86db1e22008-01-29 14:53:40 +010035
36/**
37 * blk_execute_rq_nowait - insert a request into queue for execution
38 * @q: queue to insert the request in
39 * @bd_disk: matching gendisk
40 * @rq: request to insert
41 * @at_head: insert request at head or tail of queue
42 * @done: I/O completion handler
43 *
44 * Description:
Randy Dunlap710027a2008-08-19 20:13:11 +020045 * Insert a fully prepared request at the back of the I/O scheduler queue
Jens Axboe86db1e22008-01-29 14:53:40 +010046 * for execution. Don't wait for completion.
Muthukumar Rattye81ca6f2012-06-29 15:31:49 +000047 *
48 * Note:
49 * This function will invoke @done directly if the queue is dead.
Jens Axboe86db1e22008-01-29 14:53:40 +010050 */
51void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
52 struct request *rq, int at_head,
53 rq_end_io_fn *done)
54{
55 int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
Roland Dreier893d2902012-11-22 02:00:11 -080056 bool is_pm_resume;
Jens Axboe86db1e22008-01-29 14:53:40 +010057
Tejun Heo8ba61432011-12-14 00:33:37 +010058 WARN_ON(irqs_disabled());
James Bottomleybfe159a2011-07-07 15:45:40 -050059
Jens Axboe86db1e22008-01-29 14:53:40 +010060 rq->rq_disk = bd_disk;
Jens Axboe86db1e22008-01-29 14:53:40 +010061 rq->end_io = done;
Jens Axboe320ae512013-10-24 09:20:05 +010062
Ming Lei43a5e4e2013-12-26 21:31:35 +080063 /*
64 * don't check dying flag for MQ because the request won't
65 * be resued after dying flag is set
66 */
Jens Axboe320ae512013-10-24 09:20:05 +010067 if (q->mq_ops) {
68 blk_mq_insert_request(q, rq, true);
69 return;
70 }
71
Roland Dreier893d2902012-11-22 02:00:11 -080072 /*
73 * need to check this before __blk_run_queue(), because rq can
74 * be freed before that returns.
75 */
76 is_pm_resume = rq->cmd_type == REQ_TYPE_PM_RESUME;
Muthukumar Rattye81ca6f2012-06-29 15:31:49 +000077
78 spin_lock_irq(q->queue_lock);
79
Bart Van Assche3f3299d2012-11-28 13:42:38 +010080 if (unlikely(blk_queue_dying(q))) {
Mike Christie76521132013-09-18 08:33:55 -060081 rq->cmd_flags |= REQ_QUIET;
Muthukumar Rattye81ca6f2012-06-29 15:31:49 +000082 rq->errors = -ENXIO;
Mike Christie76521132013-09-18 08:33:55 -060083 __blk_end_request_all(rq, rq->errors);
Muthukumar Rattye81ca6f2012-06-29 15:31:49 +000084 spin_unlock_irq(q->queue_lock);
85 return;
86 }
87
Jens Axboe7eaceac2011-03-10 08:52:07 +010088 __elv_add_request(q, rq, where);
Christoph Hellwig24ecfbe2011-04-18 11:41:33 +020089 __blk_run_queue(q);
Tao Maaddd0a02011-05-05 15:10:05 -060090 /* the queue is stopped so it won't be run */
Roland Dreier893d2902012-11-22 02:00:11 -080091 if (is_pm_resume)
Bart Van Asschec246e802012-12-06 14:32:01 +010092 __blk_run_queue_uncond(q);
Jens Axboe86db1e22008-01-29 14:53:40 +010093 spin_unlock_irq(q->queue_lock);
94}
95EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
96
97/**
98 * blk_execute_rq - insert a request into queue for execution
99 * @q: queue to insert the request in
100 * @bd_disk: matching gendisk
101 * @rq: request to insert
102 * @at_head: insert request at head or tail of queue
103 *
104 * Description:
Randy Dunlap710027a2008-08-19 20:13:11 +0200105 * Insert a fully prepared request at the back of the I/O scheduler queue
Jens Axboe86db1e22008-01-29 14:53:40 +0100106 * for execution and wait for completion.
107 */
108int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk,
109 struct request *rq, int at_head)
110{
111 DECLARE_COMPLETION_ONSTACK(wait);
112 char sense[SCSI_SENSE_BUFFERSIZE];
113 int err = 0;
Mark Lord4b197762010-09-24 09:51:13 -0400114 unsigned long hang_check;
Jens Axboe86db1e22008-01-29 14:53:40 +0100115
Jens Axboe86db1e22008-01-29 14:53:40 +0100116 if (!rq->sense) {
117 memset(sense, 0, sizeof(sense));
118 rq->sense = sense;
119 rq->sense_len = 0;
120 }
121
122 rq->end_io_data = &wait;
123 blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
Mark Lord4b197762010-09-24 09:51:13 -0400124
125 /* Prevent hang_check timer from firing at us during very long I/O */
126 hang_check = sysctl_hung_task_timeout_secs;
127 if (hang_check)
Vladimir Davydov55770222013-02-14 18:19:59 +0400128 while (!wait_for_completion_io_timeout(&wait, hang_check * (HZ/2)));
Mark Lord4b197762010-09-24 09:51:13 -0400129 else
Vladimir Davydov55770222013-02-14 18:19:59 +0400130 wait_for_completion_io(&wait);
Jens Axboe86db1e22008-01-29 14:53:40 +0100131
132 if (rq->errors)
133 err = -EIO;
134
135 return err;
136}
Jens Axboe86db1e22008-01-29 14:53:40 +0100137EXPORT_SYMBOL(blk_execute_rq);