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 rq->rq_disk = bd_disk; 54 rq->end_io = done; 55 WARN_ON(irqs_disabled()); 56 spin_lock_irq(q->queue_lock); 57 __elv_add_request(q, rq, where, 1); 58 __generic_unplug_device(q); 59 /* the queue is stopped so it won't be plugged+unplugged */ 60 if (rq->cmd_type == REQ_TYPE_PM_RESUME) 61 q->request_fn(q); 62 spin_unlock_irq(q->queue_lock); 63} 64EXPORT_SYMBOL_GPL(blk_execute_rq_nowait); 65 66/** 67 * blk_execute_rq - insert a request into queue for execution 68 * @q: queue to insert the request in 69 * @bd_disk: matching gendisk 70 * @rq: request to insert 71 * @at_head: insert request at head or tail of queue 72 * 73 * Description: 74 * Insert a fully prepared request at the back of the I/O scheduler queue 75 * for execution and wait for completion. 76 */ 77int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk, 78 struct request *rq, int at_head) 79{ 80 DECLARE_COMPLETION_ONSTACK(wait); 81 char sense[SCSI_SENSE_BUFFERSIZE]; 82 int err = 0; 83 84 /* 85 * we need an extra reference to the request, so we can look at 86 * it after io completion 87 */ 88 rq->ref_count++; 89 90 if (!rq->sense) { 91 memset(sense, 0, sizeof(sense)); 92 rq->sense = sense; 93 rq->sense_len = 0; 94 } 95 96 rq->end_io_data = &wait; 97 blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq); 98 wait_for_completion(&wait); 99 100 if (rq->errors) 101 err = -EIO; 102 103 return err; 104} 105EXPORT_SYMBOL(blk_execute_rq); 106