Commit | Line | Data |
---|---|---|
86db1e29 JA |
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 | |
710027a4 | 19 | * @error: end I/O status of the request |
86db1e29 | 20 | */ |
681a561b | 21 | static void blk_end_sync_rq(struct request *rq, int error) |
86db1e29 JA |
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 | } | |
86db1e29 JA |
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: | |
710027a4 | 44 | * Insert a fully prepared request at the back of the I/O scheduler queue |
86db1e29 | 45 | * for execution. Don't wait for completion. |
e81ca6fe MR |
46 | * |
47 | * Note: | |
48 | * This function will invoke @done directly if the queue is dead. | |
86db1e29 JA |
49 | */ |
50 | void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk, | |
51 | struct request *rq, int at_head, | |
52 | rq_end_io_fn *done) | |
53 | { | |
54 | int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK; | |
893d290f | 55 | bool is_pm_resume; |
86db1e29 | 56 | |
8ba61435 | 57 | WARN_ON(irqs_disabled()); |
e81ca6fe MR |
58 | |
59 | rq->rq_disk = bd_disk; | |
60 | rq->end_io = done; | |
893d290f RD |
61 | /* |
62 | * need to check this before __blk_run_queue(), because rq can | |
63 | * be freed before that returns. | |
64 | */ | |
65 | is_pm_resume = rq->cmd_type == REQ_TYPE_PM_RESUME; | |
e81ca6fe | 66 | |
8ba61435 TH |
67 | spin_lock_irq(q->queue_lock); |
68 | ||
3f3299d5 | 69 | if (unlikely(blk_queue_dying(q))) { |
bfe159a5 JB |
70 | rq->errors = -ENXIO; |
71 | if (rq->end_io) | |
72 | rq->end_io(rq, rq->errors); | |
e81ca6fe | 73 | spin_unlock_irq(q->queue_lock); |
bfe159a5 JB |
74 | return; |
75 | } | |
76 | ||
7eaceacc | 77 | __elv_add_request(q, rq, where); |
24ecfbe2 | 78 | __blk_run_queue(q); |
addd0a09 | 79 | /* the queue is stopped so it won't be run */ |
893d290f | 80 | if (is_pm_resume) |
c246e80d | 81 | __blk_run_queue_uncond(q); |
86db1e29 JA |
82 | spin_unlock_irq(q->queue_lock); |
83 | } | |
84 | EXPORT_SYMBOL_GPL(blk_execute_rq_nowait); | |
85 | ||
86 | /** | |
87 | * blk_execute_rq - insert a request into queue for execution | |
88 | * @q: queue to insert the request in | |
89 | * @bd_disk: matching gendisk | |
90 | * @rq: request to insert | |
91 | * @at_head: insert request at head or tail of queue | |
92 | * | |
93 | * Description: | |
710027a4 | 94 | * Insert a fully prepared request at the back of the I/O scheduler queue |
86db1e29 JA |
95 | * for execution and wait for completion. |
96 | */ | |
97 | int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk, | |
98 | struct request *rq, int at_head) | |
99 | { | |
100 | DECLARE_COMPLETION_ONSTACK(wait); | |
101 | char sense[SCSI_SENSE_BUFFERSIZE]; | |
102 | int err = 0; | |
4b197769 | 103 | unsigned long hang_check; |
86db1e29 JA |
104 | |
105 | /* | |
106 | * we need an extra reference to the request, so we can look at | |
107 | * it after io completion | |
108 | */ | |
109 | rq->ref_count++; | |
110 | ||
111 | if (!rq->sense) { | |
112 | memset(sense, 0, sizeof(sense)); | |
113 | rq->sense = sense; | |
114 | rq->sense_len = 0; | |
115 | } | |
116 | ||
117 | rq->end_io_data = &wait; | |
118 | blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq); | |
4b197769 ML |
119 | |
120 | /* Prevent hang_check timer from firing at us during very long I/O */ | |
121 | hang_check = sysctl_hung_task_timeout_secs; | |
122 | if (hang_check) | |
123 | while (!wait_for_completion_timeout(&wait, hang_check * (HZ/2))); | |
124 | else | |
125 | wait_for_completion(&wait); | |
86db1e29 JA |
126 | |
127 | if (rq->errors) | |
128 | err = -EIO; | |
129 | ||
130 | return err; | |
131 | } | |
86db1e29 | 132 | EXPORT_SYMBOL(blk_execute_rq); |