blob: 7ea04325d02f56c8f830292005d0096b033d8fe1
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 | #include <linux/blk-mq.h> |
9 | #include <linux/sched/sysctl.h> |
10 | |
11 | #include "blk.h" |
12 | |
13 | /* |
14 | * for max sense size |
15 | */ |
16 | #include <scsi/scsi_cmnd.h> |
17 | |
18 | /** |
19 | * blk_end_sync_rq - executes a completion event on a request |
20 | * @rq: request to complete |
21 | * @error: end I/O status of the request |
22 | */ |
23 | static void blk_end_sync_rq(struct request *rq, int error) |
24 | { |
25 | struct completion *waiting = rq->end_io_data; |
26 | |
27 | rq->end_io_data = NULL; |
28 | |
29 | /* |
30 | * complete last, if this is a stack request the process (and thus |
31 | * the rq pointer) could be invalid right after this complete() |
32 | */ |
33 | complete(waiting); |
34 | } |
35 | |
36 | /** |
37 | * blk_execute_rq_nowait - insert a request into queue for execution |
38 | * @q: queue to insert the request in |
39 | * @bd_disk: matching gendisk |
40 | * @rq: request to insert |
41 | * @at_head: insert request at head or tail of queue |
42 | * @done: I/O completion handler |
43 | * |
44 | * Description: |
45 | * Insert a fully prepared request at the back of the I/O scheduler queue |
46 | * for execution. Don't wait for completion. |
47 | * |
48 | * Note: |
49 | * This function will invoke @done directly if the queue is dead. |
50 | */ |
51 | void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk, |
52 | struct request *rq, int at_head, |
53 | rq_end_io_fn *done) |
54 | { |
55 | int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK; |
56 | |
57 | WARN_ON(irqs_disabled()); |
58 | WARN_ON(rq->cmd_type == REQ_TYPE_FS); |
59 | |
60 | rq->rq_disk = bd_disk; |
61 | rq->end_io = done; |
62 | |
63 | /* |
64 | * don't check dying flag for MQ because the request won't |
65 | * be reused after dying flag is set |
66 | */ |
67 | if (q->mq_ops) { |
68 | blk_mq_insert_request(rq, at_head, true, false); |
69 | return; |
70 | } |
71 | |
72 | spin_lock_irq(q->queue_lock); |
73 | |
74 | if (unlikely(blk_queue_dying(q))) { |
75 | rq->cmd_flags |= REQ_QUIET; |
76 | rq->errors = -ENXIO; |
77 | __blk_end_request_all(rq, rq->errors); |
78 | spin_unlock_irq(q->queue_lock); |
79 | return; |
80 | } |
81 | |
82 | __elv_add_request(q, rq, where); |
83 | __blk_run_queue(q); |
84 | spin_unlock_irq(q->queue_lock); |
85 | } |
86 | EXPORT_SYMBOL_GPL(blk_execute_rq_nowait); |
87 | |
88 | /** |
89 | * blk_execute_rq - insert a request into queue for execution |
90 | * @q: queue to insert the request in |
91 | * @bd_disk: matching gendisk |
92 | * @rq: request to insert |
93 | * @at_head: insert request at head or tail of queue |
94 | * |
95 | * Description: |
96 | * Insert a fully prepared request at the back of the I/O scheduler queue |
97 | * for execution and wait for completion. |
98 | */ |
99 | int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk, |
100 | struct request *rq, int at_head) |
101 | { |
102 | DECLARE_COMPLETION_ONSTACK(wait); |
103 | char sense[SCSI_SENSE_BUFFERSIZE]; |
104 | int err = 0; |
105 | unsigned long hang_check; |
106 | |
107 | if (!rq->sense) { |
108 | memset(sense, 0, sizeof(sense)); |
109 | rq->sense = sense; |
110 | rq->sense_len = 0; |
111 | } |
112 | |
113 | rq->end_io_data = &wait; |
114 | blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq); |
115 | |
116 | /* Prevent hang_check timer from firing at us during very long I/O */ |
117 | hang_check = sysctl_hung_task_timeout_secs; |
118 | if (hang_check) |
119 | while (!wait_for_completion_io_timeout(&wait, hang_check * (HZ/2))); |
120 | else |
121 | wait_for_completion_io(&wait); |
122 | |
123 | if (rq->errors) |
124 | err = -EIO; |
125 | |
126 | if (rq->sense == sense) { |
127 | rq->sense = NULL; |
128 | rq->sense_len = 0; |
129 | } |
130 | |
131 | return err; |
132 | } |
133 | EXPORT_SYMBOL(blk_execute_rq); |
134 |