/block/blk-exec.c
C | 119 lines | 60 code | 15 blank | 44 comment | 8 complexity | 9d0241f7fea88d6f3eb025f460518788 MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.0, AGPL-1.0
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 9#include "blk.h" 10 11/* 12 * for max sense size 13 */ 14#include <scsi/scsi_cmnd.h> 15 16/** 17 * blk_end_sync_rq - executes a completion event on a request 18 * @rq: request to complete 19 * @error: end I/O status of the request 20 */ 21static void blk_end_sync_rq(struct request *rq, int error) 22{ 23 struct completion *waiting = rq->end_io_data; 24 25 rq->end_io_data = NULL; 26 __blk_put_request(rq->q, rq); 27 28 /* 29 * complete last, if this is a stack request the process (and thus 30 * the rq pointer) could be invalid right after this complete() 31 */ 32 complete(waiting); 33} 34 35/** 36 * blk_execute_rq_nowait - insert a request into queue for execution 37 * @q: queue to insert the request in 38 * @bd_disk: matching gendisk 39 * @rq: request to insert 40 * @at_head: insert request at head or tail of queue 41 * @done: I/O completion handler 42 * 43 * Description: 44 * Insert a fully prepared request at the back of the I/O scheduler queue 45 * for execution. Don't wait for completion. 46 */ 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 53 if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) { 54 rq->errors = -ENXIO; 55 if (rq->end_io) 56 rq->end_io(rq, rq->errors); 57 return; 58 } 59 60 rq->rq_disk = bd_disk; 61 rq->end_io = done; 62 WARN_ON(irqs_disabled()); 63 spin_lock_irq(q->queue_lock); 64 __elv_add_request(q, rq, where); 65 __blk_run_queue(q); 66 /* the queue is stopped so it won't be run */ 67 if (rq->cmd_type == REQ_TYPE_PM_RESUME) 68 q->request_fn(q); 69 spin_unlock_irq(q->queue_lock); 70} 71EXPORT_SYMBOL_GPL(blk_execute_rq_nowait); 72 73/** 74 * blk_execute_rq - insert a request into queue for execution 75 * @q: queue to insert the request in 76 * @bd_disk: matching gendisk 77 * @rq: request to insert 78 * @at_head: insert request at head or tail of queue 79 * 80 * Description: 81 * Insert a fully prepared request at the back of the I/O scheduler queue 82 * for execution and wait for completion. 83 */ 84int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk, 85 struct request *rq, int at_head) 86{ 87 DECLARE_COMPLETION_ONSTACK(wait); 88 char sense[SCSI_SENSE_BUFFERSIZE]; 89 int err = 0; 90 unsigned long hang_check; 91 92 /* 93 * we need an extra reference to the request, so we can look at 94 * it after io completion 95 */ 96 rq->ref_count++; 97 98 if (!rq->sense) { 99 memset(sense, 0, sizeof(sense)); 100 rq->sense = sense; 101 rq->sense_len = 0; 102 } 103 104 rq->end_io_data = &wait; 105 blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq); 106 107 /* Prevent hang_check timer from firing at us during very long I/O */ 108 hang_check = sysctl_hung_task_timeout_secs; 109 if (hang_check) 110 while (!wait_for_completion_timeout(&wait, hang_check * (HZ/2))); 111 else 112 wait_for_completion(&wait); 113 114 if (rq->errors) 115 err = -EIO; 116 117 return err; 118} 119EXPORT_SYMBOL(blk_execute_rq);