LXR linux/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 */
  20static 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 = (void *)(uintptr_t)error;
  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 to I/O scheduler for execution
  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 gendisk *bd_disk, struct request *rq,
  48                           int at_head, rq_end_io_fn *done)
  49{
  50        WARN_ON(irqs_disabled());
  51        WARN_ON(!blk_rq_is_passthrough(rq));
  52
  53        rq->rq_disk = bd_disk;
  54        rq->end_io = done;
  55
  56        blk_account_io_start(rq);
  57
  58        /*
  59         * don't check dying flag for MQ because the request won't
  60         * be reused after dying flag is set
  61         */
  62        blk_mq_sched_insert_request(rq, at_head, true, false);
  63}
  64EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
  65
  66static bool blk_rq_is_poll(struct request *rq)
  67{
  68        return rq->mq_hctx && rq->mq_hctx->type == HCTX_TYPE_POLL;
  69}
  70
  71static void blk_rq_poll_completion(struct request *rq, struct completion *wait)
  72{
  73        do {
  74                blk_poll(rq->q, request_to_qc_t(rq->mq_hctx, rq), true);
  75                cond_resched();
  76        } while (!completion_done(wait));
  77}
  78
  79/**
  80 * blk_execute_rq - insert a request into queue for execution
  81 * @bd_disk:    matching gendisk
  82 * @rq:         request to insert
  83 * @at_head:    insert request at head or tail of queue
  84 *
  85 * Description:
  86 *    Insert a fully prepared request at the back of the I/O scheduler queue
  87 *    for execution and wait for completion.
  88 * Return: The blk_status_t result provided to blk_mq_end_request().
  89 */
  90blk_status_t blk_execute_rq(struct gendisk *bd_disk, struct request *rq, int at_head)
  91{
  92        DECLARE_COMPLETION_ONSTACK(wait);
  93        unsigned long hang_check;
  94
  95        rq->end_io_data = &wait;
  96        blk_execute_rq_nowait(bd_disk, rq, at_head, blk_end_sync_rq);
  97
  98        /* Prevent hang_check timer from firing at us during very long I/O */
  99        hang_check = sysctl_hung_task_timeout_secs;
 100
 101        if (blk_rq_is_poll(rq))
 102                blk_rq_poll_completion(rq, &wait);
 103        else if (hang_check)
 104                while (!wait_for_completion_io_timeout(&wait, hang_check * (HZ/2)));
 105        else
 106                wait_for_completion_io(&wait);
 107
 108        return (blk_status_t)(uintptr_t)rq->end_io_data;
 109}
 110EXPORT_SYMBOL(blk_execute_rq);
 111