Revert "Staging: comedi: integer overflow in do_insnlist_ioctl()"
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / block / blk-exec.c
bloba1ebceb332f963ee366aa7ebed60d69c4e1c11cb
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>
9 #include "blk.h"
12 * for max sense size
14 #include <scsi/scsi_cmnd.h>
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
21 static void blk_end_sync_rq(struct request *rq, int error)
23 struct completion *waiting = rq->end_io_data;
25 rq->end_io_data = NULL;
26 __blk_put_request(rq->q, rq);
29 * complete last, if this is a stack request the process (and thus
30 * the rq pointer) could be invalid right after this complete()
32 complete(waiting);
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
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.
47 void 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)
51 int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
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;
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);
71 EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
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
80 * Description:
81 * Insert a fully prepared request at the back of the I/O scheduler queue
82 * for execution and wait for completion.
84 int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk,
85 struct request *rq, int at_head)
87 DECLARE_COMPLETION_ONSTACK(wait);
88 char sense[SCSI_SENSE_BUFFERSIZE];
89 int err = 0;
90 unsigned long hang_check;
93 * we need an extra reference to the request, so we can look at
94 * it after io completion
96 rq->ref_count++;
98 if (!rq->sense) {
99 memset(sense, 0, sizeof(sense));
100 rq->sense = sense;
101 rq->sense_len = 0;
104 rq->end_io_data = &wait;
105 blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
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);
114 if (rq->errors)
115 err = -EIO;
117 return err;
119 EXPORT_SYMBOL(blk_execute_rq);