| 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 | #include <linux/blk-mq.h> |
| 9 | #include <linux/sched/sysctl.h> |
| 10 | |
| 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 |
| 21 | * @error: end I/O status of the request |
| 22 | */ |
| 23 | static void blk_end_sync_rq(struct request *rq, int error) |
| 24 | { |
| 25 | struct completion *waiting = rq->end_io_data; |
| 26 | |
| 27 | rq->end_io_data = NULL; |
| 28 | |
| 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 | } |
| 35 | |
| 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: |
| 45 | * Insert a fully prepared request at the back of the I/O scheduler queue |
| 46 | * for execution. Don't wait for completion. |
| 47 | * |
| 48 | * Note: |
| 49 | * This function will invoke @done directly if the queue is dead. |
| 50 | */ |
| 51 | void 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; |
| 56 | |
| 57 | WARN_ON(irqs_disabled()); |
| 58 | WARN_ON(rq->cmd_type == REQ_TYPE_FS); |
| 59 | |
| 60 | rq->rq_disk = bd_disk; |
| 61 | rq->end_io = done; |
| 62 | |
| 63 | /* |
| 64 | * don't check dying flag for MQ because the request won't |
| 65 | * be resued after dying flag is set |
| 66 | */ |
| 67 | if (q->mq_ops) { |
| 68 | blk_mq_insert_request(rq, at_head, true, false); |
| 69 | return; |
| 70 | } |
| 71 | |
| 72 | spin_lock_irq(q->queue_lock); |
| 73 | |
| 74 | if (unlikely(blk_queue_dying(q))) { |
| 75 | rq->cmd_flags |= REQ_QUIET; |
| 76 | rq->errors = -ENXIO; |
| 77 | __blk_end_request_all(rq, rq->errors); |
| 78 | spin_unlock_irq(q->queue_lock); |
| 79 | return; |
| 80 | } |
| 81 | |
| 82 | __elv_add_request(q, rq, where); |
| 83 | __blk_run_queue(q); |
| 84 | spin_unlock_irq(q->queue_lock); |
| 85 | } |
| 86 | EXPORT_SYMBOL_GPL(blk_execute_rq_nowait); |
| 87 | |
| 88 | /** |
| 89 | * blk_execute_rq - insert a request into queue for execution |
| 90 | * @q: queue to insert the request in |
| 91 | * @bd_disk: matching gendisk |
| 92 | * @rq: request to insert |
| 93 | * @at_head: insert request at head or tail of queue |
| 94 | * |
| 95 | * Description: |
| 96 | * Insert a fully prepared request at the back of the I/O scheduler queue |
| 97 | * for execution and wait for completion. |
| 98 | */ |
| 99 | int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk, |
| 100 | struct request *rq, int at_head) |
| 101 | { |
| 102 | DECLARE_COMPLETION_ONSTACK(wait); |
| 103 | char sense[SCSI_SENSE_BUFFERSIZE]; |
| 104 | int err = 0; |
| 105 | unsigned long hang_check; |
| 106 | |
| 107 | if (!rq->sense) { |
| 108 | memset(sense, 0, sizeof(sense)); |
| 109 | rq->sense = sense; |
| 110 | rq->sense_len = 0; |
| 111 | } |
| 112 | |
| 113 | rq->end_io_data = &wait; |
| 114 | blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq); |
| 115 | |
| 116 | /* Prevent hang_check timer from firing at us during very long I/O */ |
| 117 | hang_check = sysctl_hung_task_timeout_secs; |
| 118 | if (hang_check) |
| 119 | while (!wait_for_completion_io_timeout(&wait, hang_check * (HZ/2))); |
| 120 | else |
| 121 | wait_for_completion_io(&wait); |
| 122 | |
| 123 | if (rq->errors) |
| 124 | err = -EIO; |
| 125 | |
| 126 | if (rq->sense == sense) { |
| 127 | rq->sense = NULL; |
| 128 | rq->sense_len = 0; |
| 129 | } |
| 130 | |
| 131 | return err; |
| 132 | } |
| 133 | EXPORT_SYMBOL(blk_execute_rq); |