LXR linux/block/blk-exec.c

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