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>
14 #include <scsi/scsi_cmnd.h>
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()
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
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
,
51 int where
= at_head
? ELEVATOR_INSERT_FRONT
: ELEVATOR_INSERT_BACK
;
53 if (unlikely(test_bit(QUEUE_FLAG_DEAD
, &q
->queue_flags
))) {
56 rq
->end_io(rq
, rq
->errors
);
60 rq
->rq_disk
= bd_disk
;
62 WARN_ON(irqs_disabled());
63 spin_lock_irq(q
->queue_lock
);
64 __elv_add_request(q
, rq
, where
);
66 /* the queue is stopped so it won't be run */
67 if (rq
->cmd_type
== REQ_TYPE_PM_RESUME
)
69 spin_unlock_irq(q
->queue_lock
);
71 EXPORT_SYMBOL_GPL(blk_execute_rq_nowait
);
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
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
];
90 unsigned long hang_check
;
93 * we need an extra reference to the request, so we can look at
94 * it after io completion
99 memset(sense
, 0, sizeof(sense
));
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
;
110 while (!wait_for_completion_timeout(&wait
, hang_check
* (HZ
/2)));
112 wait_for_completion(&wait
);
119 EXPORT_SYMBOL(blk_execute_rq
);