2 * Functions related to setting various queue properties from drivers
4 #include <linux/kernel.h>
5 #include <linux/module.h>
7 #include <linux/blkdev.h>
8 #include <linux/blk-mq.h>
9 #include <linux/sched/sysctl.h>
16 #include <scsi/scsi_cmnd.h>
19 * blk_end_sync_rq - executes a completion event on a request
20 * @rq: request to complete
21 * @error: end I/O status of the request
23 static void blk_end_sync_rq(struct request *rq, int error)
25 struct completion *waiting = rq->end_io_data;
27 rq->end_io_data = NULL;
30 * complete last, if this is a stack request the process (and thus
31 * the rq pointer) could be invalid right after this complete()
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
45 * Insert a fully prepared request at the back of the I/O scheduler queue
46 * for execution. Don't wait for completion.
49 * This function will invoke @done directly if the queue is dead.
51 void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
52 struct request *rq, int at_head,
55 int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
58 WARN_ON(irqs_disabled());
60 rq->rq_disk = bd_disk;
64 * don't check dying flag for MQ because the request won't
65 * be resued after dying flag is set
68 blk_mq_insert_request(rq, at_head, true, false);
73 * need to check this before __blk_run_queue(), because rq can
74 * be freed before that returns.
76 is_pm_resume = rq->cmd_type == REQ_TYPE_PM_RESUME;
78 spin_lock_irq(q->queue_lock);
80 if (unlikely(blk_queue_dying(q))) {
81 rq->cmd_flags |= REQ_QUIET;
83 __blk_end_request_all(rq, rq->errors);
84 spin_unlock_irq(q->queue_lock);
88 __elv_add_request(q, rq, where);
90 /* the queue is stopped so it won't be run */
92 __blk_run_queue_uncond(q);
93 spin_unlock_irq(q->queue_lock);
95 EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
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
105 * Insert a fully prepared request at the back of the I/O scheduler queue
106 * for execution and wait for completion.
108 int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk,
109 struct request *rq, int at_head)
111 DECLARE_COMPLETION_ONSTACK(wait);
112 char sense[SCSI_SENSE_BUFFERSIZE];
114 unsigned long hang_check;
117 memset(sense, 0, sizeof(sense));
122 rq->end_io_data = &wait;
123 blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
125 /* Prevent hang_check timer from firing at us during very long I/O */
126 hang_check = sysctl_hung_task_timeout_secs;
128 while (!wait_for_completion_io_timeout(&wait, hang_check * (HZ/2)));
130 wait_for_completion_io(&wait);
137 EXPORT_SYMBOL(blk_execute_rq);