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>
12 #include "blk-mq-sched.h"
17 #include <scsi/scsi_cmnd.h>
20 * blk_end_sync_rq - executes a completion event on a request
21 * @rq: request to complete
22 * @error: end I/O status of the request
24 static void blk_end_sync_rq(struct request *rq, int error)
26 struct completion *waiting = rq->end_io_data;
28 rq->end_io_data = NULL;
31 * complete last, if this is a stack request the process (and thus
32 * the rq pointer) could be invalid right after this complete()
38 * blk_execute_rq_nowait - insert a request into queue for execution
39 * @q: queue to insert the request in
40 * @bd_disk: matching gendisk
41 * @rq: request to insert
42 * @at_head: insert request at head or tail of queue
43 * @done: I/O completion handler
46 * Insert a fully prepared request at the back of the I/O scheduler queue
47 * for execution. Don't wait for completion.
50 * This function will invoke @done directly if the queue is dead.
52 void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
53 struct request *rq, int at_head,
56 int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
58 WARN_ON(irqs_disabled());
59 WARN_ON(rq->cmd_type == REQ_TYPE_FS);
61 rq->rq_disk = bd_disk;
65 * don't check dying flag for MQ because the request won't
66 * be reused after dying flag is set
69 blk_mq_sched_insert_request(rq, at_head, true, false);
73 spin_lock_irq(q->queue_lock);
75 if (unlikely(blk_queue_dying(q))) {
76 rq->rq_flags |= RQF_QUIET;
78 __blk_end_request_all(rq, rq->errors);
79 spin_unlock_irq(q->queue_lock);
83 __elv_add_request(q, rq, where);
85 spin_unlock_irq(q->queue_lock);
87 EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
90 * blk_execute_rq - insert a request into queue for execution
91 * @q: queue to insert the request in
92 * @bd_disk: matching gendisk
93 * @rq: request to insert
94 * @at_head: insert request at head or tail of queue
97 * Insert a fully prepared request at the back of the I/O scheduler queue
98 * for execution and wait for completion.
100 int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk,
101 struct request *rq, int at_head)
103 DECLARE_COMPLETION_ONSTACK(wait);
104 char sense[SCSI_SENSE_BUFFERSIZE];
106 unsigned long hang_check;
109 memset(sense, 0, sizeof(sense));
114 rq->end_io_data = &wait;
115 blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
117 /* Prevent hang_check timer from firing at us during very long I/O */
118 hang_check = sysctl_hung_task_timeout_secs;
120 while (!wait_for_completion_io_timeout(&wait, hang_check * (HZ/2)));
122 wait_for_completion_io(&wait);
127 if (rq->sense == sense) {
134 EXPORT_SYMBOL(blk_execute_rq);