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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"
Jens Axboebd166ef2017-01-17 06:03:22 -070012#include "blk-mq-sched.h"
Jens Axboe86db1e22008-01-29 14:53:40 +010013
Jens Axboe86db1e22008-01-29 14:53:40 +010014/**
15 * blk_end_sync_rq - executes a completion event on a request
16 * @rq: request to complete
Randy Dunlap710027a2008-08-19 20:13:11 +020017 * @error: end I/O status of the request
Jens Axboe86db1e22008-01-29 14:53:40 +010018 */
Christoph Hellwig2a842ac2017-06-03 09:38:04 +020019static void blk_end_sync_rq(struct request *rq, blk_status_t error)
Jens Axboe86db1e22008-01-29 14:53:40 +010020{
21 struct completion *waiting = rq->end_io_data;
22
23 rq->end_io_data = NULL;
Jens Axboe86db1e22008-01-29 14:53:40 +010024
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}
Jens Axboe86db1e22008-01-29 14:53:40 +010031
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:
Randy Dunlap710027a2008-08-19 20:13:11 +020041 * Insert a fully prepared request at the back of the I/O scheduler queue
Jens Axboe86db1e22008-01-29 14:53:40 +010042 * for execution. Don't wait for completion.
Muthukumar Rattye81ca6f2012-06-29 15:31:49 +000043 *
44 * Note:
45 * This function will invoke @done directly if the queue is dead.
Jens Axboe86db1e22008-01-29 14:53:40 +010046 */
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
Tejun Heo8ba61432011-12-14 00:33:37 +010053 WARN_ON(irqs_disabled());
Christoph Hellwig57292b52017-01-31 16:57:29 +010054 WARN_ON(!blk_rq_is_passthrough(rq));
James Bottomleybfe159a2011-07-07 15:45:40 -050055
Jens Axboe86db1e22008-01-29 14:53:40 +010056 rq->rq_disk = bd_disk;
Jens Axboe86db1e22008-01-29 14:53:40 +010057 rq->end_io = done;
Jens Axboe320ae512013-10-24 09:20:05 +010058
Ming Lei43a5e4e2013-12-26 21:31:35 +080059 /*
60 * don't check dying flag for MQ because the request won't
Bart Van Assche68bdf1a2016-07-19 08:18:06 -070061 * be reused after dying flag is set
Ming Lei43a5e4e2013-12-26 21:31:35 +080062 */
Jens Axboe320ae512013-10-24 09:20:05 +010063 if (q->mq_ops) {
Jens Axboebd6737f2017-01-27 01:00:47 -070064 blk_mq_sched_insert_request(rq, at_head, true, false, false);
Jens Axboe320ae512013-10-24 09:20:05 +010065 return;
66 }
67
Muthukumar Rattye81ca6f2012-06-29 15:31:49 +000068 spin_lock_irq(q->queue_lock);
69
Bart Van Assche3f3299d2012-11-28 13:42:38 +010070 if (unlikely(blk_queue_dying(q))) {
Christoph Hellwige8064022016-10-20 15:12:13 +020071 rq->rq_flags |= RQF_QUIET;
Christoph Hellwig2a842ac2017-06-03 09:38:04 +020072 __blk_end_request_all(rq, BLK_STS_IOERR);
Muthukumar Rattye81ca6f2012-06-29 15:31:49 +000073 spin_unlock_irq(q->queue_lock);
74 return;
75 }
76
Jens Axboe7eaceac2011-03-10 08:52:07 +010077 __elv_add_request(q, rq, where);
Christoph Hellwig24ecfbe2011-04-18 11:41:33 +020078 __blk_run_queue(q);
Jens Axboe86db1e22008-01-29 14:53:40 +010079 spin_unlock_irq(q->queue_lock);
80}
81EXPORT_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:
Randy Dunlap710027a2008-08-19 20:13:11 +020091 * Insert a fully prepared request at the back of the I/O scheduler queue
Jens Axboe86db1e22008-01-29 14:53:40 +010092 * for execution and wait for completion.
93 */
Christoph Hellwigb7819b92017-04-20 16:02:55 +020094void blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk,
Jens Axboe86db1e22008-01-29 14:53:40 +010095 struct request *rq, int at_head)
96{
97 DECLARE_COMPLETION_ONSTACK(wait);
Mark Lord4b197762010-09-24 09:51:13 -040098 unsigned long hang_check;
Jens Axboe86db1e22008-01-29 14:53:40 +010099
Jens Axboe86db1e22008-01-29 14:53:40 +0100100 rq->end_io_data = &wait;
101 blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
Mark Lord4b197762010-09-24 09:51:13 -0400102
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)
Vladimir Davydov55770222013-02-14 18:19:59 +0400106 while (!wait_for_completion_io_timeout(&wait, hang_check * (HZ/2)));
Mark Lord4b197762010-09-24 09:51:13 -0400107 else
Vladimir Davydov55770222013-02-14 18:19:59 +0400108 wait_for_completion_io(&wait);
Jens Axboe86db1e22008-01-29 14:53:40 +0100109}
Jens Axboe86db1e22008-01-29 14:53:40 +0100110EXPORT_SYMBOL(blk_execute_rq);