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  */
  19 static 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  */
  47 void 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 }
  63 EXPORT_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  */
  76 void 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 }
  92 EXPORT_SYMBOL(blk_execute_rq);