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 = (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  */
  47 void 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 }
  64 EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
  65
  66 static bool blk_rq_is_poll(struct request *rq)
  67 {
  68         return rq->mq_hctx && rq->mq_hctx->type == HCTX_TYPE_POLL;
  69 }
  70
  71 static 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  */
  90 blk_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 }
 110 EXPORT_SYMBOL(blk_execute_rq);