block/blk-exec.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Functions related to setting various queue properties from drivers
   4  */
   5 #include <linux/kernel.h>
   6 #include <linux/module.h>
   7 #include <linux/bio.h>
   8 #include <linux/blkdev.h>
   9 #include <linux/blk-mq.h>
  10 #include <linux/sched/sysctl.h>
  11
  12 #include "blk.h"
  13 #include "blk-mq-sched.h"
  14
  15 /**
  16  * blk_end_sync_rq - executes a completion event on a request
  17  * @rq: request to complete
  18  * @error: end I/O status of the request
  19  */
  20 static void blk_end_sync_rq(struct request *rq, blk_status_t error)
  21 {
  22         struct completion *waiting = rq->end_io_data;
  23
  24         rq->end_io_data = NULL;
  25
  26         /*
  27          * complete last, if this is a stack request the process (and thus
  28          * the rq pointer) could be invalid right after this complete()
  29          */
  30         complete(waiting);
  31 }
  32
  33 /**
  34  * blk_execute_rq_nowait - insert a request into queue for execution
  35  * @q:          queue to insert the request in
  36  * @bd_disk:    matching gendisk
  37  * @rq:         request to insert
  38  * @at_head:    insert request at head or tail of queue
  39  * @done:       I/O completion handler
  40  *
  41  * Description:
  42  *    Insert a fully prepared request at the back of the I/O scheduler queue
  43  *    for execution.  Don't wait for completion.
  44  *
  45  * Note:
  46  *    This function will invoke @done directly if the queue is dead.
  47  */
  48 void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
  49                            struct request *rq, int at_head,
  50                            rq_end_io_fn *done)
  51 {
  52         WARN_ON(irqs_disabled());
  53         WARN_ON(!blk_rq_is_passthrough(rq));
  54
  55         rq->rq_disk = bd_disk;
  56         rq->end_io = done;
  57
  58         blk_account_io_start(rq, true);
  59
  60         /*
  61          * don't check dying flag for MQ because the request won't
  62          * be reused after dying flag is set
  63          */
  64         blk_mq_sched_insert_request(rq, at_head, true, false);
  65 }
  66 EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
  67
  68 /**
  69  * blk_execute_rq - insert a request into queue for execution
  70  * @q:          queue to insert the request in
  71  * @bd_disk:    matching gendisk
  72  * @rq:         request to insert
  73  * @at_head:    insert request at head or tail of queue
  74  *
  75  * Description:
  76  *    Insert a fully prepared request at the back of the I/O scheduler queue
  77  *    for execution and wait for completion.
  78  */
  79 void blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk,
  80                    struct request *rq, int at_head)
  81 {
  82         DECLARE_COMPLETION_ONSTACK(wait);
  83         unsigned long hang_check;
  84
  85         rq->end_io_data = &wait;
  86         blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
  87
  88         /* Prevent hang_check timer from firing at us during very long I/O */
  89         hang_check = sysctl_hung_task_timeout_secs;
  90         if (hang_check)
  91                 while (!wait_for_completion_io_timeout(&wait, hang_check * (HZ/2)));
  92         else
  93                 wait_for_completion_io(&wait);
  94 }
  95 EXPORT_SYMBOL(blk_execute_rq);